{"title":"Narrowband Filters","description":"\u003cdiv\u003e\n  \u003cp\u003e\n    Narrowband imaging is what makes deep-sky astrophotography possible from a Canadian city. By passing only a few nanometres around a specific emission line, these filters reject almost all artificial light and most moonlight, so a nebula that is invisible visually from a suburban driveway becomes a viable multi-hour imaging target. David Astro stocks narrowband filters in Canada, held in Canadian inventory.\n  \u003c\/p\u003e\n  \u003cp\u003e\n    Bandwidth choice interacts with your telescope's focal ratio in ways that catch people out. Tell us your optic and camera and we will recommend a bandwidth that will actually perform in your system.\n  \u003c\/p\u003e\n\u003c\/div\u003e\n\u003c!-- more --\u003e\n\u003cdiv\u003e\n  \u003ch2\u003eEmission Lines, Bandwidth and Focal Ratio\u003c\/h2\u003e\n  \u003cp\u003e\n    Narrowband filters isolate the specific wavelengths that ionized gas emits. Narrower is not always better, because the passband shifts in a fast light cone and the exposure requirement rises.\n  \u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eHydrogen-alpha at 656.3 nm:\u003c\/strong\u003e The strongest and most widely used emission line, showing nebulosity in extraordinary detail and working well even under a bright Moon.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eOxygen III at 500.7 nm:\u003c\/strong\u003e Reveals planetary nebulae, supernova remnants and the outer shells of emission nebulae; typically the weakest signal of the three and needs the most integration.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSulphur II at 672.4 nm:\u003c\/strong\u003e The third channel of the Hubble palette, adding structural differentiation in bright nebulae.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003e3 to 5 nm bandwidth:\u003c\/strong\u003e Maximum contrast under light pollution, best suited to f\/5 and slower systems and to accurate, temperature-compensated focus.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003e6 to 12 nm bandwidth:\u003c\/strong\u003e More forgiving of fast optics and shorter exposures, and a better match for one-shot colour cameras and systems faster than f\/4.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eDual and multi-band filters:\u003c\/strong\u003e Pass two or more lines simultaneously for one-shot colour cameras, giving narrowband-like contrast without a filter wheel.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n  \u003ch2\u003eWhy Choose David Astro for Narrowband Filters\u003c\/h2\u003e\n  \u003cp\u003e\n    A filter that is wrong for your focal ratio will underperform in a way that looks like a quality problem but is a specification problem.\n  \u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFocal ratio matched:\u003c\/strong\u003e Below roughly f\/4 the incident cone shifts a narrow passband off the emission line. We recommend bandwidths or fast-optic designs that account for this.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSizing to sensor and wheel geometry:\u003c\/strong\u003e We calculate the filter size needed to avoid vignetting given your sensor diagonal and filter-to-sensor distance.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFocus offsets explained:\u003c\/strong\u003e Narrowband channels often need per-filter focus offsets, and we help set them up so you are not refocusing manually every filter change.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAuthorized dealer:\u003c\/strong\u003e Genuine filters with verified coatings and full manufacturer warranty, in Canadian stock.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eDomestic shipping:\u003c\/strong\u003e No duties or brokerage fees for Canadian orders.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n  \u003ch2\u003eNarrowband Filters in Canada — Frequently Asked Questions\u003c\/h2\u003e\n  \u003cdl\u003e\n    \u003cdt\u003e\u003cstrong\u003eCan I use narrowband with a colour camera?\u003c\/strong\u003e\u003c\/dt\u003e\n    \u003cdd\u003eYes, most effectively with a dual-band filter that passes Ha and OIII together, since a colour sensor's Bayer array can separate them. Single-line filters work but waste three quarters of the pixels.\u003c\/dd\u003e\n    \u003cdt\u003e\u003cstrong\u003eIs a 3 nm filter always better than 7 nm?\u003c\/strong\u003e\u003c\/dt\u003e\n    \u003cdd\u003eNot in fast systems. Below about f\/4 the steep light cone shifts the passband and a 3 nm filter can lose signal. In an f\/6 system under city skies, 3 nm gives noticeably better contrast.\u003c\/dd\u003e\n    \u003cdt\u003e\u003cstrong\u003eCan I image through a full Moon?\u003c\/strong\u003e\u003c\/dt\u003e\n    \u003cdd\u003eWith Ha, largely yes. Moonlight is broadband scattered sunlight, and a narrow Ha filter rejects nearly all of it. OIII suffers more because its wavelength sits closer to the peak of scattered light.\u003c\/dd\u003e\n    \u003cdt\u003e\u003cstrong\u003eHow long should narrowband exposures be?\u003c\/strong\u003e\u003c\/dt\u003e\n    \u003cdd\u003eLonger than broadband — typically 300 to 600 seconds per sub, depending on focal ratio and camera read noise. Total integration for a good narrowband image is usually measured in tens of hours.\u003c\/dd\u003e\n  \u003c\/dl\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n  \u003ch2\u003eImaging from a light-polluted site?\u003c\/h2\u003e\n  \u003cp\u003eTell us your telescope, camera and focal ratio and we will recommend the right bandwidths. Ships from Canada.\u003c\/p\u003e\n\u003c\/div\u003e","products":[{"product_id":"william-optics-stc-astro-duo-narrowband-filter","title":"William Optics STC Astro Duo-Narrowband Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDual-Bandpass for H-Alpha and Oxygen-III\u003c\/li\u003e\n\u003cli\u003eSuppresses Urban Light Pollution\u003c\/li\u003e\n\u003cli\u003eIon Beam-Assisted Deposition (IBAD) Coatings\u003c\/li\u003e\n\u003cli\u003eHigh Durability and Easy-to-Clean Optical Surfaces\u003c\/li\u003e\n\u003cli\u003eMatte Black Anodized, Teflon-Coated Anti-Flare Frame\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eWilliam Optics STC Astro Duo-Narrowband Filter\u003c\/h2\u003e\n\u003cp\u003eThe William Optics STC Astro Duo-Narrowband Filter is engineered to isolate the two most important emission lines for nebula photography, Hydrogen-alpha (Hα) and Oxygen-III (OIII), while aggressively blocking light pollution. By utilizing advanced Ion Beam-Assisted Deposition (IBAD) coatings, this filter delivers exceptional signal-to-noise ratio and maintains spectral stability through changing temperatures, ensuring consistent results from your light-polluted backyard.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe Duo-Narrowband Advantage: Isolating Hα and OIII Emission Lines\u003c\/h3\u003e\n\u003cp\u003eUnlike broadband filters that pass a wide swath of the spectrum, the STC Astro Duo-Narrowband Filter targets the specific wavelengths emitted by planetary and emission nebulae. This selective transmission dramatically increases contrast by rejecting sodium and mercury vapor light from city streetlights, as well as natural skyglow, darkening the background and making faint nebulosity stand out.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eIBAD Coatings: Durability and Spectral Stability\u003c\/h3\u003e\n\u003cp\u003eThe filter employs Ion Beam-Assisted Deposition (IBAD) coating technology, which creates an extremely dense, hard, and moisture-resistant optical surface. This process ensures the filter's bandpass characteristics will not shift due to changes in temperature or humidity during an imaging session—a critical factor for maintaining consistent color balance and data quality. The robust coatings also make the filter surface easier to clean without risk of damage.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eEngineered Frame: Anti-Reflection and Easy Handling\u003c\/h3\u003e\n\u003cp\u003eEvery component is designed to minimize artifacts. The filter's frame is constructed from matte black anodized aluminum to absorb stray light and prevent internal reflections that can cause halos around bright stars. A Teflon coating on the frame's edge ensures smooth installation and removal from a filter wheel or camera nosepiece, reducing the risk of binding or cross-threading.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eDuo-Narrowband vs. Broadband LPR Filters: A Sharper Cut\u003c\/h3\u003e\n\u003cp\u003eWhile a standard Light Pollution Reduction (LPR) filter offers a modest improvement from the city, a duo-narrowband design like the STC represents a significant step up for imaging emission nebulae. Where a broadband LPR filter might pass a wide range of blue and red light, the STC filter's tight focus on just the Hα and OIII lines provides a much darker sky background. This makes it the superior choice for objects like the Orion Nebula (M42) or the Lagoon Nebula (M8), though less ideal for broadband targets like galaxies and reflection nebulae which emit light across the entire spectrum.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main advantage of the William Optics STC Astro Duo-Narrowband Filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIts primary advantage is isolating the key \u003cstrong\u003eH-alpha\u003c\/strong\u003e and \u003cstrong\u003eOIII\u003c\/strong\u003e wavelengths emitted by most nebulae. This allows you to capture high-contrast images from light-polluted urban and suburban locations by rejecting the specific wavelengths associated with artificial lighting.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the STC Duo-Narrowband Filter perform on the Orion Nebula (M42) from a city?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt will perform exceptionally well. The Orion Nebula (M42) is rich in both Hydrogen-alpha and Oxygen-III emissions. The William Optics STC Astro Duo-Narrowband Filter will darken the light-polluted sky background, dramatically increasing the contrast and revealing faint, extended structures in the nebula that would otherwise be invisible from a city.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the STC Duo-Narrowband Filter suitable for imaging galaxies like Andromeda (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this is not the ideal filter for broadband targets like galaxies. Galaxies and reflection nebulae shine by reflecting starlight across the entire visible spectrum. Because the \u003cstrong\u003eWilliam Optics STC Astro Duo-Narrowband Filter\u003c\/strong\u003e blocks most of that spectrum, it will significantly dim the galaxy and produce poor results. A broadband LPR filter or unfiltered imaging from a dark site is better for galaxies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the IBAD coating on the STC Duo-Narrowband Filter improve my images?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003eIon Beam-Assisted Deposition (IBAD)\u003c\/strong\u003e process creates a very stable coating. This prevents the filter's transmission bands from shifting with temperature or humidity changes throughout the night. This stability ensures you get consistent color data and performance from dusk till dawn, a crucial factor for long-exposure astrophotography.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat makes the frame of the STC Duo-Narrowband Filter special?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe frame is designed to enhance image quality and usability. It features:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMatte Black Anodizing:\u003c\/strong\u003e Absorbs stray light to prevent internal reflections and halos.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTeflon Coating:\u003c\/strong\u003e Allows for smooth, easy installation and removal from your imaging train without jamming.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the William Optics STC Duo-Narrowband Filter for visual observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile technically possible, it is not recommended. Narrowband filters like this one block a tremendous amount of light, and the resulting image through an eyepiece would be extremely dim. These filters are designed specifically for the long exposures used in astrophotography with one-shot-color or monochrome cameras.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/william-optics-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eWilliam Optics 2-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":44967225590045,"sku":"WO-YF-STC-ADN","price":660.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/William-Optics-STC-Astro-Duo-Narrowband-Filter-YF-STC-ADN-1__15183.1596133266.1280.1280.jpg?v=1684339179"},{"product_id":"chroma-h-alpha-filter-3nm","title":"Chroma H-alpha Filter - 3nm","description":"\u003c!-- more --\u003e\u003cp\u003eH-alpha filters are essential for imaging nebulae and other objects which are rich in ionized hydrogen. At 656.3nm, a narrow-band emission filter is required to separate H-alpha from the SII doublet (671.6nm and 673.1nm).\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eFilters designed for use with CCD and for f\/4.0 or slower\u003c\/li\u003e\n\u003cli\u003eNo reflections leading to image distortions or \"back reflections\"\u003c\/li\u003e\n\u003cli\u003eTransmitted wavefront better than 0.25 waves\/inch\u003c\/li\u003e\n\u003cli\u003eDurable sputter coatings\u003c\/li\u003e\n\u003cli\u003eParallelism: \u0026lt; 30 arcsec\u003c\/li\u003e\n\u003cli\u003eThickness: 3.0 +\/-0.05mm\u003c\/li\u003e\n\u003cli\u003eExtremely durable coatings withstand humidity changes and extreme temperature fluxes and remain spectrally accurate\u003c\/li\u003e\n\u003cli\u003ein CWL and band pass adherence\u003c\/li\u003e\n\u003cli\u003eCapable of manufacturing large filters for large detectors: 50mm x 50mm, 65mm up to 76.2mm and 101.6mm square\u003c\/li\u003e\n\u003cli\u003eAll filters manufactured in Vermont\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eChroma manufactures the highest quality astronomy filters with durable, sputtered hard coatings using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission.\u003c\/p\u003e\u003cp\u003eHighly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity. All filters may be used with apertures of f\/4 or smaller. They provide custom coating services for more demanding imaging applications requiring larger apertures such as f\/3 or f\/2. They also can provide larger sizes and unique passbands upon request.\u003c\/p\u003e","brand":"Chroma","offers":[{"title":"1.25\" Round Mounted","offer_id":44967243612445,"sku":"CT-27001-1.25M","price":805.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967243645213,"sku":"CT-27001-31D","price":805.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967243677981,"sku":"CT-27001-36D","price":1085.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967243710749,"sku":"CT-27001-2M","price":1820.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967243743517,"sku":"CT-27001-50D","price":1750.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967243776285,"sku":"CT-27001-50X50","price":2170.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-H-alpha-3nm-Filter__77186.1596071504.1280.1280.jpg?v=1684339497"},{"product_id":"chroma-h-alpha-filter-5nm","title":"Chroma H-alpha Filter - 5nm","description":"\u003c!-- more --\u003e\u003cp\u003eH-alpha filters are essential for imaging nebulae and other objects which are rich in ionized hydrogen. At 656.3nm, a narrow-band emission filter is required to separate H-alpha from the SII doublet (671.6nm and 673.1nm).\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eFilters designed for use with CCD and for f\/4.0 or slower\u003c\/li\u003e\n\u003cli\u003eNo reflections leading to image distortions or \"back reflections\"\u003c\/li\u003e\n\u003cli\u003eTransmitted wavefront better than 0.25 waves\/inch\u003c\/li\u003e\n\u003cli\u003eDurable sputter coatings\u003c\/li\u003e\n\u003cli\u003eParallelism: \u0026lt; 30 arcsec\u003c\/li\u003e\n\u003cli\u003eThickness: 3.0 +\/-0.05mm\u003c\/li\u003e\n\u003cli\u003eExtremely durable coatings withstand humidity changes and extreme temperature fluxes and remain spectrally accurate\u003c\/li\u003e\n\u003cli\u003ein CWL and band pass adherence\u003c\/li\u003e\n\u003cli\u003eCapable of manufacturing large filters for large detectors: 50mm x 50mm, 65mm up to 76.2mm and 101.6mm square\u003c\/li\u003e\n\u003cli\u003eAll filters manufactured in Vermont\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eChroma manufactures the highest quality astronomy filters with durable, sputtered hard coatings using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission.\u003c\/p\u003e\u003cp\u003eHighly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity. All filters may be used with apertures of f\/4 or smaller. They provide custom coating services for more demanding imaging applications requiring larger apertures such as f\/3 or f\/2. They also can provide larger sizes and unique passbands upon request.\u003c\/p\u003e","brand":"Chroma","offers":[{"title":"1.25\" Round Mounted","offer_id":44967243809053,"sku":"CT-27002-1.25M","price":644.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967243841821,"sku":"CT-27002-31D","price":644.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967243874589,"sku":"CT-27002-36D","price":868.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967243907357,"sku":"CT-27002-2M","price":1365.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967243940125,"sku":"CT-27002-50D","price":1295.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967243972893,"sku":"CT-27002-50X50","price":1932.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-H-alpha-5nm-Filter__56496.1596071505.1280.1280.jpg?v=1684339501"},{"product_id":"chroma-h-alpha-filter-8nm","title":"Chroma H-alpha Filter - 8nm","description":"\u003c!-- more --\u003e\u003cp\u003eH-alpha filters are essential for imaging nebulae and other objects which are rich in ionized hydrogen. At 656.3nm, a narrow-band emission filter is required to separate H-alpha from the SII doublet (671.6nm and 673.1nm).\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eFilters designed for use with CCD and for f\/4.0 or slower\u003c\/li\u003e\n\u003cli\u003eNo reflections leading to image distortions or \"back reflections\"\u003c\/li\u003e\n\u003cli\u003eTransmitted wavefront better than 0.25 waves\/inch\u003c\/li\u003e\n\u003cli\u003eDurable sputter coatings\u003c\/li\u003e\n\u003cli\u003eParallelism: \u0026lt; 30 arcsec\u003c\/li\u003e\n\u003cli\u003eThickness: 3.0 +\/-0.05mm\u003c\/li\u003e\n\u003cli\u003eExtremely durable coatings withstand humidity changes and extreme temperature fluxes and remain spectrally accurate\u003c\/li\u003e\n\u003cli\u003ein CWL and band pass adherence\u003c\/li\u003e\n\u003cli\u003eCapable of manufacturing large filters for large detectors: 50mm x 50mm, 65mm up to 76.2mm and 101.6mm square\u003c\/li\u003e\n\u003cli\u003eAll filters manufactured in Vermont\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eChroma manufactures the highest quality astronomy filters with durable, sputtered hard coatings using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission.\u003c\/p\u003e\u003cp\u003eHighly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity. All filters may be used with apertures of f\/4 or smaller. They provide custom coating services for more demanding imaging applications requiring larger apertures such as f\/3 or f\/2. They also can provide larger sizes and unique passbands upon request.\u003c\/p\u003e","brand":"Chroma","offers":[{"title":"1.25\" Round Mounted","offer_id":44967244038429,"sku":"CT-27003-1.25M","price":385.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967244071197,"sku":"CT-27003-31D","price":385.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967244103965,"sku":"CT-27003-36D","price":497.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967244136733,"sku":"CT-27003-2M","price":1162.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967244169501,"sku":"CT-27003-50D","price":1092.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967244202269,"sku":"CT-27003-50X50","price":1106.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-H-alpha-8nm-Filter__69220.1596071506.1280.1280.jpg?v=1684339504"},{"product_id":"chroma-h-beta-filter-3nm","title":"Chroma H-beta Filter - 3nm","description":"\u003c!-- more --\u003e\u003cp\u003eH-beta filters are also useful for imaging nebulae and objects rich in ionized hydrogen. At 486.1nm, a narrow-band filter is required to separate H-beta from nearby blue and green spectral lines. Although weaker than the H-alpha line, this is often used for visual detection as the longer red wavelengths of H-alpha are difficult to detect by eye.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eFilters designed for use with CCD and for f\/4.0 or slower\u003c\/li\u003e\n\u003cli\u003eNo reflections leading to image distortions or \"back reflections\"\u003c\/li\u003e\n\u003cli\u003eTransmitted wavefront better than 0.25 waves\/inch\u003c\/li\u003e\n\u003cli\u003eDurable sputter coatings\u003c\/li\u003e\n\u003cli\u003eParallelism: \u0026lt; 30 arcsec\u003c\/li\u003e\n\u003cli\u003eThickness: 3.0 +\/-0.05mm\u003c\/li\u003e\n\u003cli\u003eExtremely durable coatings withstand humidity changes and extreme temperature fluxes and remain spectrally accurate\u003c\/li\u003e\n\u003cli\u003ein CWL and band pass adherence\u003c\/li\u003e\n\u003cli\u003eCapable of manufacturing large filters for large detectors: 50mm x 50mm, 65mm up to 76.2mm and 101.6mm square\u003c\/li\u003e\n\u003cli\u003eAll filters manufactured in Vermont\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eChroma manufactures the highest quality astronomy filters with durable, sputtered hard coatings using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission.\u003c\/p\u003e\u003cp\u003eHighly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity. All filters may be used with apertures of f\/4 or smaller. They provide custom coating services for more demanding imaging applications requiring larger apertures such as f\/3 or f\/2. They also can provide larger sizes and unique passbands upon request.\u003c\/p\u003e","brand":"Chroma","offers":[{"title":"1.25\" Round Mounted","offer_id":44967244235037,"sku":"CT-27004-1.25M","price":805.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967244267805,"sku":"CT-27004-31D","price":805.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967244300573,"sku":"CT-27004-36D","price":1085.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967244333341,"sku":"CT-27004-2M","price":1820.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967244366109,"sku":"CT-27004-50D","price":1750.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967244398877,"sku":"CT-27004-50X50","price":2170.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-H-beta-3nm-Filter__82264.1596071507.1280.1280.jpg?v=1684339701"},{"product_id":"chroma-h-beta-filter-5nm","title":"Chroma H-beta Filter - 5nm","description":"\u003c!-- more --\u003e\u003cp\u003eH-beta filters are also useful for imaging nebulae and objects rich in ionized hydrogen. At 486.1nm, a narrow-band filter is required to separate H-beta from nearby blue and green spectral lines. Although weaker than the H-alpha line, this is often used for visual detection as the longer red wavelengths of H-alpha are difficult to detect by eye.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eFilters designed for use with CCD and for f\/4.0 or slower\u003c\/li\u003e\n\u003cli\u003eNo reflections leading to image distortions or \"back reflections\"\u003c\/li\u003e\n\u003cli\u003eTransmitted wavefront better than 0.25 waves\/inch\u003c\/li\u003e\n\u003cli\u003eDurable sputter coatings\u003c\/li\u003e\n\u003cli\u003eParallelism: \u0026lt; 30 arcsec\u003c\/li\u003e\n\u003cli\u003eThickness: 3.0 +\/-0.05mm\u003c\/li\u003e\n\u003cli\u003eExtremely durable coatings withstand humidity changes and extreme temperature fluxes and remain spectrally accurate\u003c\/li\u003e\n\u003cli\u003ein CWL and band pass adherence\u003c\/li\u003e\n\u003cli\u003eCapable of manufacturing large filters for large detectors: 50mm x 50mm, 65mm up to 76.2mm and 101.6mm square\u003c\/li\u003e\n\u003cli\u003eAll filters manufactured in Vermont\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eChroma manufactures the highest quality astronomy filters with durable, sputtered hard coatings using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission.\u003c\/p\u003e\u003cp\u003eHighly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity. All filters may be used with apertures of f\/4 or smaller. They provide custom coating services for more demanding imaging applications requiring larger apertures such as f\/3 or f\/2. They also can provide larger sizes and unique passbands upon request.\u003c\/p\u003e","brand":"Chroma","offers":[{"title":"1.25\" Round Mounted","offer_id":44967244464413,"sku":"CT-27005-1.25M","price":644.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967244497181,"sku":"CT-27005-31D","price":644.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967244529949,"sku":"CT-27005-36D","price":868.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967244562717,"sku":"CT-27005-2M","price":1365.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967244595485,"sku":"CT-27005-50D","price":1295.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967244628253,"sku":"CT-27005-50X50","price":1932.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-H-beta-5nm-Filter__19579.1596071508.1280.1280.jpg?v=1684339704"},{"product_id":"chroma-sii-filter-3nm","title":"Chroma SII Filter - 3nm","description":"\u003c!-- more --\u003e\u003cp\u003eSII filters isolate the spectral emission of singly ionized sulfur atoms, also common in nebulae. Emission is at two lines occurring as a doublet, at 671.6 and 673.1 nm. This filter also separates sulfur emission from H-alpha emission (656.3nm).\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eFilters designed for use with CCD and for f\/4.0 or slower\u003c\/li\u003e\n\u003cli\u003eNo reflections leading to image distortions or \"back reflections\"\u003c\/li\u003e\n\u003cli\u003eTransmitted wavefront better than 0.25 waves\/inch\u003c\/li\u003e\n\u003cli\u003eDurable sputter coatings\u003c\/li\u003e\n\u003cli\u003eParallelism: \u0026lt; 30 arcsec\u003c\/li\u003e\n\u003cli\u003eThickness: 3.0 +\/-0.05mm\u003c\/li\u003e\n\u003cli\u003eExtremely durable coatings withstand humidity changes and extreme temperature fluxes and remain spectrally accurate\u003c\/li\u003e\n\u003cli\u003ein CWL and band pass adherence\u003c\/li\u003e\n\u003cli\u003eCapable of manufacturing large filters for large detectors: 50mm x 50mm, 65mm up to 76.2mm and 101.6mm square\u003c\/li\u003e\n\u003cli\u003eAll filters manufactured in Vermont\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eChroma manufactures the highest quality astronomy filters with durable, sputtered hard coatings using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission.\u003c\/p\u003e\u003cp\u003eHighly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity. All filters may be used with apertures of f\/4 or smaller. They provide custom coating services for more demanding imaging applications requiring larger apertures such as f\/3 or f\/2. They also can provide larger sizes and unique passbands upon request.\u003c\/p\u003e","brand":"Chroma","offers":[{"title":"1.25\" Round Mounted","offer_id":44967244759325,"sku":"CT-27009-1.25M","price":805.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967244792093,"sku":"CT-27009-31D","price":805.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967244824861,"sku":"CT-27009-36D","price":1085.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967244857629,"sku":"CT-27009-2M","price":1820.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967244890397,"sku":"CT-27009-50D","price":1750.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967244923165,"sku":"CT-27009-50X50","price":2170.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-SII-3nm-Filter__16961.1596071510.1280.1280.jpg?v=1684339708"},{"product_id":"chroma-sii-filter-5nm","title":"Chroma SII Filter - 5nm","description":"\u003c!-- more --\u003e\u003cp\u003eSII filters isolate the spectral emission of singly ionized sulfur atoms, also common in nebulae. Emission is at two lines occurring as a doublet, at 671.6 and 673.1 nm. This filter also separates sulfur emission from H-alpha emission (656.3nm).\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eFilters designed for use with CCD and for f\/4.0 or slower\u003c\/li\u003e\n\u003cli\u003eNo reflections leading to image distortions or \"back reflections\"\u003c\/li\u003e\n\u003cli\u003eTransmitted wavefront better than 0.25 waves\/inch\u003c\/li\u003e\n\u003cli\u003eDurable sputter coatings\u003c\/li\u003e\n\u003cli\u003eParallelism: \u0026lt; 30 arcsec\u003c\/li\u003e\n\u003cli\u003eThickness: 3.0 +\/-0.05mm\u003c\/li\u003e\n\u003cli\u003eExtremely durable coatings withstand humidity changes and extreme temperature fluxes and remain spectrally accurate\u003c\/li\u003e\n\u003cli\u003ein CWL and band pass adherence\u003c\/li\u003e\n\u003cli\u003eCapable of manufacturing large filters for large detectors: 50mm x 50mm, 65mm up to 76.2mm and 101.6mm square\u003c\/li\u003e\n\u003cli\u003eAll filters manufactured in Vermont\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eChroma manufactures the highest quality astronomy filters with durable, sputtered hard coatings using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission.\u003c\/p\u003e\u003cp\u003eHighly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity. All filters may be used with apertures of f\/4 or smaller. They provide custom coating services for more demanding imaging applications requiring larger apertures such as f\/3 or f\/2. They also can provide larger sizes and unique passbands upon request.\u003c\/p\u003e","brand":"Chroma","offers":[{"title":"1.25\" Round Mounted","offer_id":44967244955933,"sku":"CT-27010-1.25M","price":644.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967244988701,"sku":"CT-27010-31D","price":644.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967245021469,"sku":"CT-27010-36D","price":868.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967245054237,"sku":"CT-27010-2M","price":1365.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967245087005,"sku":"CT-27010-50D","price":1295.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967245119773,"sku":"CT-27010-50X50","price":1932.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-SII-5nm-Filter__94086.1596071511.1280.1280.jpg?v=1684339711"},{"product_id":"chroma-sii-filter-8nm","title":"Chroma SII Filter - 8nm","description":"\u003c!-- more --\u003e\u003cp\u003eSII filters isolate the spectral emission of singly ionized sulfur atoms, also common in nebulae. Emission is at two lines occurring as a doublet, at 671.6 and 673.1 nm. This filter also separates sulfur emission from H-alpha emission (656.3nm).\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eFilters designed for use with CCD and for f\/4.0 or slower\u003c\/li\u003e\n\u003cli\u003eNo reflections leading to image distortions or \"back reflections\"\u003c\/li\u003e\n\u003cli\u003eTransmitted wavefront better than 0.25 waves\/inch\u003c\/li\u003e\n\u003cli\u003eDurable sputter coatings\u003c\/li\u003e\n\u003cli\u003eParallelism: \u0026lt; 30 arcsec\u003c\/li\u003e\n\u003cli\u003eThickness: 3.0 +\/-0.05mm\u003c\/li\u003e\n\u003cli\u003eExtremely durable coatings withstand humidity changes and extreme temperature fluxes and remain spectrally accurate\u003c\/li\u003e\n\u003cli\u003ein CWL and band pass adherence\u003c\/li\u003e\n\u003cli\u003eCapable of manufacturing large filters for large detectors: 50mm x 50mm, 65mm up to 76.2mm and 101.6mm square\u003c\/li\u003e\n\u003cli\u003eAll filters manufactured in Vermont\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eChroma manufactures the highest quality astronomy filters with durable, sputtered hard coatings using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission.\u003c\/p\u003e\u003cp\u003eHighly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity. All filters may be used with apertures of f\/4 or smaller. They provide custom coating services for more demanding imaging applications requiring larger apertures such as f\/3 or f\/2. 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After H-alpha, this is the next most common emission when imaging nebulae\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eFilters designed for use with CCD and for f\/4.0 or slower\u003c\/li\u003e\n\u003cli\u003eNo reflections leading to image distortions or \"back reflections\"\u003c\/li\u003e\n\u003cli\u003eTransmitted wavefront better than 0.25 waves\/inch\u003c\/li\u003e\n\u003cli\u003eDurable sputter coatings\u003c\/li\u003e\n\u003cli\u003eParallelism: \u0026lt; 30 arcsec\u003c\/li\u003e\n\u003cli\u003eThickness: 3.0 +\/-0.05mm\u003c\/li\u003e\n\u003cli\u003eExtremely durable coatings withstand humidity changes and extreme temperature fluxes and remain spectrally accurate\u003c\/li\u003e\n\u003cli\u003ein CWL and band pass adherence\u003c\/li\u003e\n\u003cli\u003eCapable of manufacturing large filters for large detectors: 50mm x 50mm, 65mm up to 76.2mm and 101.6mm square\u003c\/li\u003e\n\u003cli\u003eAll filters manufactured in Vermont\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eChroma manufactures the highest quality astronomy filters with durable, sputtered hard coatings using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission.\u003c\/p\u003e\u003cp\u003eHighly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity. All filters may be used with apertures of f\/4 or smaller. They provide custom coating services for more demanding imaging applications requiring larger apertures such as f\/3 or f\/2. They also can provide larger sizes and unique passbands upon request.\u003c\/p\u003e","brand":"Chroma","offers":[{"title":"1.25\" Round Mounted","offer_id":44967245381917,"sku":"CT-27006-1.25M","price":805.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967245414685,"sku":"CT-27006-31D","price":805.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967245447453,"sku":"CT-27006-36D","price":1085.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967245480221,"sku":"CT-27006-2M","price":1820.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967245512989,"sku":"CT-27006-50D","price":1750.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967245545757,"sku":"CT-27006-50X50","price":2170.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-OIII-3nm-Filter__30198.1596071513.1280.1280.jpg?v=1684339508"},{"product_id":"chroma-oiii-filter-5nm","title":"Chroma OIII Filter - 5nm","description":"\u003c!-- more --\u003e\u003cp\u003eChroma’s OIII filters isolate the 500.7nm primary emission line of doubly ionized oxygen. After H-alpha, this is the next most common emission when imaging nebulae\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eFilters designed for use with CCD and for f\/4.0 or slower\u003c\/li\u003e\n\u003cli\u003eNo reflections leading to image distortions or \"back reflections\"\u003c\/li\u003e\n\u003cli\u003eTransmitted wavefront better than 0.25 waves\/inch\u003c\/li\u003e\n\u003cli\u003eDurable sputter coatings\u003c\/li\u003e\n\u003cli\u003eParallelism: \u0026lt; 30 arcsec\u003c\/li\u003e\n\u003cli\u003eThickness: 3.0 +\/-0.05mm\u003c\/li\u003e\n\u003cli\u003eExtremely durable coatings withstand humidity changes and extreme temperature fluxes and remain spectrally accurate\u003c\/li\u003e\n\u003cli\u003ein CWL and band pass adherence\u003c\/li\u003e\n\u003cli\u003eCapable of manufacturing large filters for large detectors: 50mm x 50mm, 65mm up to 76.2mm and 101.6mm square\u003c\/li\u003e\n\u003cli\u003eAll filters manufactured in Vermont\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eChroma manufactures the highest quality astronomy filters with durable, sputtered hard coatings using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission.\u003c\/p\u003e\u003cp\u003eHighly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity. All filters may be used with apertures of f\/4 or smaller. They provide custom coating services for more demanding imaging applications requiring larger apertures such as f\/3 or f\/2. They also can provide larger sizes and unique passbands upon request.\u003c\/p\u003e","brand":"Chroma","offers":[{"title":"1.25\" Round Mounted","offer_id":44967245611293,"sku":"CT-27007-1.25M","price":644.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967245644061,"sku":"CT-27007-31D","price":644.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967245676829,"sku":"CT-27007-36D","price":868.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967245709597,"sku":"CT-27007-2M","price":1365.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967245742365,"sku":"CT-27007-50D","price":1295.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967245775133,"sku":"CT-27007-50X50","price":1932.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-OIII-5nm-Filter__52324.1596071514.1280.1280.jpg?v=1684339511"},{"product_id":"chroma-oiii-filter-8nm","title":"Chroma OIII Filter - 8nm","description":"\u003c!-- more --\u003e\u003cp\u003eChroma’s OIII filters isolate the 500.7nm primary emission line of doubly ionized oxygen. 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All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission.\u003c\/p\u003e\u003cp\u003eHighly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity. All filters may be used with apertures of f\/4 or smaller. They provide custom coating services for more demanding imaging applications requiring larger apertures such as f\/3 or f\/2. 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All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission.\u003c\/p\u003e\u003cp\u003eHighly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity. They also can provide larger sizes and unique passbands upon request.\u003c\/p\u003e","brand":"Chroma","offers":[{"title":"1.25\" Round Mounted","offer_id":44967251378461,"sku":"CT-27001F3-1.25M","price":805.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967251411229,"sku":"CT-27001F3-31D","price":805.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967251443997,"sku":"CT-27001F3-36D","price":1085.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967251476765,"sku":"CT-27001F3-2M","price":1820.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967251509533,"sku":"CT-27001F3-50D","price":1750.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967251542301,"sku":"CT-27001F3-50X50","price":2170.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-H-alpha-3nm-Filter__61895.1596071533.1280.1280.jpg?v=1684339534"},{"product_id":"chroma-sii-filter-optimized-for-f-3-3nm","title":"Chroma SII Filter Optimized for f\/3 - 3nm","description":"\u003c!-- more --\u003e\u003cp\u003eSII filters isolate the spectral emission of singly ionized sulfur atoms, also common in nebulae. Emission is at two lines occurring as a doublet, at 671.6 and 673.1 nm. This filter also separates sulfur emission from H-alpha emission (656.3nm).\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eFilters designed for use with CCD and for f\/3.0 telescopes\u003c\/li\u003e\n\u003cli\u003eNo reflections leading to image distortions or \"back reflections\"\u003c\/li\u003e\n\u003cli\u003eTransmitted wavefront better than 0.25 waves\/inch\u003c\/li\u003e\n\u003cli\u003eDurable sputter coatings\u003c\/li\u003e\n\u003cli\u003eParallelism: \u0026lt; 30 arcsec\u003c\/li\u003e\n\u003cli\u003eThickness: 3.0 +\/-0.05mm\u003c\/li\u003e\n\u003cli\u003eExtremely durable coatings withstand humidity changes and extreme temperature fluxes and remain spectrally accurate\u003c\/li\u003e\n\u003cli\u003ein CWL and band pass adherence\u003c\/li\u003e\n\u003cli\u003eCapable of manufacturing large filters for large detectors: 50mm x 50mm, 65mm up to 76.2mm and 101.6mm square\u003c\/li\u003e\n\u003cli\u003eAll filters manufactured in Vermont\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eChroma manufactures the highest quality astronomy filters with durable, sputtered hard coatings using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission.\u003c\/p\u003e\u003cp\u003eHighly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity. They also can provide larger sizes and unique passbands upon request.\u003c\/p\u003e","brand":"Chroma","offers":[{"title":"1.25\" Round Mounted","offer_id":44967252099357,"sku":"CT-27009F3-1.25M","price":805.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967252132125,"sku":"CT-27009F3-31D","price":805.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967252164893,"sku":"CT-27009F3-36D","price":1085.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967252197661,"sku":"CT-27009F3-2M","price":1820.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967252230429,"sku":"CT-27009F3-50D","price":1750.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967252263197,"sku":"CT-27009F3-50X50","price":2170.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-SII-3nm-Filter__73590.1596071536.1280.1280.jpg?v=1684339736"},{"product_id":"chroma-oiii-filter-optimized-for-f-3-3nm","title":"Chroma OIII Filter Optimized for f\/3 - 3nm","description":"\u003c!-- more --\u003e\u003cp\u003eChroma’s OIII filters isolate the 500.7nm primary emission line of doubly ionized oxygen. After H-alpha, this is the next most common emission when imaging nebulae\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eFilters designed for use with CCD and for f\/3.0 telescopes\u003c\/li\u003e\n\u003cli\u003eNo reflections leading to image distortions or \"back reflections\"\u003c\/li\u003e\n\u003cli\u003eTransmitted wavefront better than 0.25 waves\/inch\u003c\/li\u003e\n\u003cli\u003eDurable sputter coatings\u003c\/li\u003e\n\u003cli\u003eParallelism: \u0026lt; 30 arcsec\u003c\/li\u003e\n\u003cli\u003eThickness: 3.0 +\/-0.05mm\u003c\/li\u003e\n\u003cli\u003eExtremely durable coatings withstand humidity changes and extreme temperature fluxes and remain spectrally accurate\u003c\/li\u003e\n\u003cli\u003ein CWL and band pass adherence\u003c\/li\u003e\n\u003cli\u003eCapable of manufacturing large filters for large detectors: 50mm x 50mm, 65mm up to 76.2mm and 101.6mm square\u003c\/li\u003e\n\u003cli\u003eAll filters manufactured in Vermont\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eChroma manufactures the highest quality astronomy filters with durable, sputtered hard coatings using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission.\u003c\/p\u003e\u003cp\u003eHighly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity. 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American Nebula). Its medium 35nm FWHM bandwidth is ideal for interline CCD cameras ( like SBIG ST-2000\/STL11000). The lower sensitivity of interline transfer CCDs benefits from the more efficient 35nm FWHM. The sharp bandpass and \u0026gt; 90% high efficiency coatings make the Baader H-Alpha filter superior to the common colored-glass based filters, all at a reasonable price.\u003cbr\u003e\u003cbr\u003eThe Baader H-Alpha filter shares the same outstanding features as all the other Baader imaging filters. Unmatched optical quality, and high efficiency hardened multicoatings result in the sharpest and highest contrast images possible.\u003c\/p\u003e\u003cp\u003e\u003cimg alt=\"H-Alpha 35nm Transmission Curve\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/t\/6\/assets\/description_image_h_alpha_ccd_35nm_curve_480x480.jpg?v=1684340632?v=1585244106\"\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eH-Alpha 35nm Transmission Curve\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003e\u003c\/p\u003e\u003cdiv data-custom-tab\u003e\n\u003cp data-custom-tab-title\u003eSpecifications\u003c\/p\u003e\n\u003cdiv\u003e\n\u003ch2\u003e1.25\"\u003c\/h2\u003e\n\u003ctable\u003e\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eMANUFACTURER\u003c\/th\u003e\n\u003ctd\u003eBaader Planetarium\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eSKU (#)\u003c\/th\u003e\n\u003ctd\u003e2458381\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eEAN CODE\u003c\/th\u003e\n\u003ctd\u003e4047825009456\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eWEIGHT (KG)\u003c\/th\u003e\n\u003ctd\u003e0.059\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eCOLOUR\u003c\/th\u003e\n\u003ctd\u003eBlack\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eTRANSMISSION RANGE\u003c\/th\u003e\n\u003ctd\u003eH-alpha\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER THICKNESS (WITHOUT CELL)\u003c\/th\u003e\n\u003ctd\u003e2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eHBW (HALFBANDWIDTH)\u003c\/th\u003e\n\u003ctd\u003e35nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eCWL (CENTRAL WAVELENGTH)\u003c\/th\u003e\n\u003ctd\u003e656,3 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eAR-COATING\u003c\/th\u003e\n\u003ctd\u003edielectrically coated, planeoptically polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER SIZE\u003c\/th\u003e\n\u003ctd\u003e1 25 inch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER USAGE\u003c\/th\u003e\n\u003ctd\u003eH-alpha, Interline-CCD, IR-Cut\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER MOUNTED\u003c\/th\u003e\n\u003ctd\u003eMounted (LPFC 6mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eTYPE OF FILTER\u003c\/th\u003e\n\u003ctd\u003eNarrowband\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eSINGLE OR SET?\u003c\/th\u003e\n\u003ctd\u003eSingle Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER SHAPE\u003c\/th\u003e\n\u003ctd\u003eround\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\n\u003ch2\u003e2\"\u003c\/h2\u003e\n\u003ctable\u003e\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eMANUFACTURER\u003c\/th\u003e\n\u003ctd\u003eBaader Planetarium\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eSKU (#)\u003c\/th\u003e\n\u003ctd\u003e2458380\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eEAN CODE\u003c\/th\u003e\n\u003ctd\u003e4047825009463\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eWEIGHT (KG)\u003c\/th\u003e\n\u003ctd\u003e0.066\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eCOLOUR\u003c\/th\u003e\n\u003ctd\u003eBlack\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eTRANSMISSION RANGE\u003c\/th\u003e\n\u003ctd\u003eH-alpha\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER THICKNESS (WITHOUT CELL)\u003c\/th\u003e\n\u003ctd\u003e2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eHBW (HALFBANDWIDTH)\u003c\/th\u003e\n\u003ctd\u003e35nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eCWL (CENTRAL WAVELENGTH)\u003c\/th\u003e\n\u003ctd\u003e656,3 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eAR-COATING\u003c\/th\u003e\n\u003ctd\u003edielectrically coated, planeoptically polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER SIZE\u003c\/th\u003e\n\u003ctd\u003e2 inch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER USAGE\u003c\/th\u003e\n\u003ctd\u003eH-alpha, Interline-CCD, IR-Cut\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER MOUNTED\u003c\/th\u003e\n\u003ctd\u003eMounted (LPFC 6mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eTYPE OF FILTER\u003c\/th\u003e\n\u003ctd\u003eNarrowband\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eSINGLE OR SET?\u003c\/th\u003e\n\u003ctd\u003eSingle Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER SHAPE\u003c\/th\u003e\n\u003ctd\u003eround\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\n\u003ch2\u003e50.8mm\u003c\/h2\u003e\n\u003ctable\u003e\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eMANUFACTURER\u003c\/th\u003e\n\u003ctd\u003eBaader Planetarium\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eSKU (#)\u003c\/th\u003e\n\u003ctd\u003e2458379\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eEAN CODE\u003c\/th\u003e\n\u003ctd\u003e4047825009470\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eWEIGHT (KG)\u003c\/th\u003e\n\u003ctd\u003e0.07\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eCOLOUR\u003c\/th\u003e\n\u003ctd\u003eBlack\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eTRANSMISSION RANGE\u003c\/th\u003e\n\u003ctd\u003eH-alpha\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER THICKNESS (WITHOUT CELL)\u003c\/th\u003e\n\u003ctd\u003e3 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eHBW (HALFBANDWIDTH)\u003c\/th\u003e\n\u003ctd\u003e35nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eCWL (CENTRAL WAVELENGTH)\u003c\/th\u003e\n\u003ctd\u003e656,3 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eAR-COATING\u003c\/th\u003e\n\u003ctd\u003edielectrically coated, planeoptically polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER SIZE\u003c\/th\u003e\n\u003ctd\u003e50.8 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER USAGE\u003c\/th\u003e\n\u003ctd\u003eH-alpha, Interline-CCD, IR-Cut\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER MOUNTED\u003c\/th\u003e\n\u003ctd\u003eUnmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eTYPE OF FILTER\u003c\/th\u003e\n\u003ctd\u003eNarrowband\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eSINGLE OR SET?\u003c\/th\u003e\n\u003ctd\u003eSingle Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER SHAPE\u003c\/th\u003e\n\u003ctd\u003eround\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\n\u003ch2\u003e50x50mm\u003c\/h2\u003e\n\u003ctable\u003e\n\u003ccolgroup\u003e\n\u003ccol width=\"25%\"\u003e\n\u003ccol\u003e\n\u003c\/colgroup\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eMANUFACTURER\u003c\/th\u003e\n\u003ctd\u003eBaader Planetarium\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eSKU (#)\u003c\/th\u003e\n\u003ctd\u003e2458379R\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eEAN CODE\u003c\/th\u003e\n\u003ctd\u003e4047825022806\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eWEIGHT (KG)\u003c\/th\u003e\n\u003ctd\u003e0.074\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eTRANSMISSION RANGE\u003c\/th\u003e\n\u003ctd\u003eH-alpha\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER THICKNESS (WITHOUT CELL)\u003c\/th\u003e\n\u003ctd\u003e3 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eHBW (HALFBANDWIDTH)\u003c\/th\u003e\n\u003ctd\u003e35nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eCWL (CENTRAL WAVELENGTH)\u003c\/th\u003e\n\u003ctd\u003e656,3 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eAR-COATING\u003c\/th\u003e\n\u003ctd\u003edielectrically coated, planeoptically polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER SIZE\u003c\/th\u003e\n\u003ctd\u003e50 x 50 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER USAGE\u003c\/th\u003e\n\u003ctd\u003eH-alpha, Interline-CCD, IR-Cut\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER MOUNTED\u003c\/th\u003e\n\u003ctd\u003eUnmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eTYPE OF FILTER\u003c\/th\u003e\n\u003ctd\u003eNarrowband\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eSINGLE OR SET?\u003c\/th\u003e\n\u003ctd\u003eSingle Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFILTER SHAPE\u003c\/th\u003e\n\u003ctd\u003esquare\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\u003cdiv class=\"moretab\" data-title=\"Downloads \u0026amp; Support\"\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/t\/6\/assets\/description_image_faq_problems_with_filters_can_have_the_strangest_causes.pdf?v=1684340622?v=1590138683\" target=\"_blank\"\u003eFAQ - Problems with filters can have the strangest causes\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/t\/6\/assets\/description_image_halos_no_problem.pdf?v=1684340636?v=1590141382\" target=\"_blank\"\u003eHalos - No Problem!\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Baader Planetarium","offers":[{"title":"1.25\" Round Mounted","offer_id":44967356629277,"sku":"BAA-2458381","price":153.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967356662045,"sku":"BAA-2458380","price":279.0,"currency_code":"CAD","in_stock":true},{"title":"50.4mm Round Unmounted Filter","offer_id":44967356694813,"sku":"BAA-2458379","price":300.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Filter","offer_id":44967356727581,"sku":"BAA-2458379R","price":370.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader-H-Alpha-CCD-Filter-35nm-1__30810.1597110905.1280.1280.jpg?v=1684341297"},{"product_id":"baader-6-5nm-f-2-highspeed-filter-set-cmos-optimized-h-alpha-o-iii-s-ii","title":"Baader 6.5nm f\/2  Highspeed Filter Set - CMOS-Optimized H-alpha\/O-III\/S-II","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eSet of 3 Narrowband Filters: H-alpha, O-III, and S-II\u003c\/li\u003e\n\u003cli\u003e6.5nm Bandpass for high-contrast imaging\u003c\/li\u003e\n\u003cli\u003eOptimized for f\/2 to f\/3.5 High-Speed Optical Systems\u003c\/li\u003e\n\u003cli\u003ePre-shifted bandpass prevents signal loss from steep light cones\u003c\/li\u003e\n\u003cli\u003eCMOS-optimized with Reflex-Blocker™ coatings to eliminate halos\u003c\/li\u003e\n\u003cli\u003eSealed coating edges prevent moisture intrusion and aging\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eBaader 6.5nm f\/2 Highspeed Filter Set - CMOS-Optimized H-alpha\/O-III\/S-II\u003c\/h2\u003e\n\u003cp\u003eThe Baader 6.5nm f\/2 Highspeed Filter Set contains three essential narrowband filters (H-alpha, O-III, S-II) specifically engineered to maintain peak transmission when used with ultra-fast astrographs like Celestron RASA or Hyperstar systems. Standard narrowband filters suffer significant signal loss at focal ratios faster than f\/4, but this 6.5nm set is pre-shifted to perfectly align with the emission lines from an f\/2 light cone, ensuring maximum signal capture. This optimization allows modern CMOS sensors to record deep, high-contrast images of emission nebulae without the reflection halos or bandpass-shift issues that compromise data from fast optical systems.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eDesigned for f\/2 Systems: Pre-Shifted for Maximum Signal\u003c\/h3\u003e\n\u003cp\u003eIn a fast optical system, light rays approach the filter at a very steep angle, causing a phenomenon known as bandpass shift, where the filter's central wavelength shifts towards blue. A standard narrowband filter used at f\/2 can shift so much that it partially blocks the very emission line you're trying to capture. Baader's f\/2 Highspeed filters solve this by pre-shifting the central wavelength of the bandpass, ensuring that at f\/2, it is perfectly centered on the H-alpha, O-III, or S-II line for peak transmission.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eCMOS-Optimized for 6.5nm Signals: Halation and Reflection Control\u003c\/h3\u003e\n\u003cp\u003eModern CMOS sensors, while incredibly sensitive, are also highly reflective. When paired with traditional filters, this can create strong halos and internal reflections around bright stars. The Baader Highspeed filters incorporate advanced Reflex-Blocker™ coatings that are hardened and optimized to suppress these reflections, delivering clean stellar profiles. Additionally, the coating edges are sealed (Life-Coat™), making them exceptionally durable and resistant to degradation from moisture, ensuring their high transmission for years of use.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e6.5nm Bandpass: High Contrast for Emission Nebulae\u003c\/h3\u003e\n\u003cp\u003eThe 6.5nm full width at half maximum (FWHM) strikes a critical balance between contrast and signal acquisition speed. This bandpass is narrow enough to dramatically darken the sky background, isolating faint nebular structures from moonlight and urban light pollution. At the same time, it is wide enough to deliver a strong signal, which is crucial for capturing data efficiently with fast f\/2 optical systems where exposure times are already significantly reduced.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eBaader f\/2 Highspeed vs. Standard Narrowband Filters\u003c\/h3\u003e\n\u003cp\u003eThe choice between this f\/2 Highspeed set and a standard narrowband filter set comes down to your telescope's focal ratio.\n\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard Filters (f\/4 and slower):\u003c\/strong\u003e These filters are designed for the shallower light cones of most refractors, SCTs, and Newtonians. Using them on an f\/2 system results in significant signal loss due to bandpass shift.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBaader f\/2 Highspeed Filters:\u003c\/strong\u003e These are purpose-built for systems from f\/2 to f\/3.5. Their pre-shifted design maximizes signal. Using them on a slower f\/8 telescope is a trade-off; the filter's center wavelength will be slightly offset from the emission line, resulting in a suboptimal, though still usable, signal.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat makes the Baader 6.5nm f\/2 Highspeed filters different from standard narrowband filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe key difference is their \u003cstrong\u003epre-shifted bandpass\u003c\/strong\u003e. Standard filters are designed for f\/4 or slower systems. When used at f\/2, the steep light cone shifts their transmission window, blocking part of the nebula's light. The Baader f\/2 Highspeed filters are manufactured to be perfectly on-band when used at f\/2, ensuring maximum signal throughput.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Baader f\/2 filters on my f\/8 Ritchey-Chrétien telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile you can, it is not optimal. These filters are pre-shifted for an f\/2 light cone. On an f\/8 system, the filter's bandpass will be slightly blue-shifted relative to the target emission line, resulting in a small reduction in signal. For f\/8 systems, a standard narrowband filter designed for slower focal ratios will deliver better results.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does \"CMOS-Optimized\" mean for the Baader Highspeed Filter Set?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt refers to the advanced \u003cstrong\u003eReflex-Blocker™ coatings\u003c\/strong\u003e applied to the filters. Modern CMOS sensors are very reflective, which can cause halos and artifacts around bright stars. These specialized coatings are designed to suppress these reflections, producing cleaner images with tighter star profiles, even on very bright targets.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the 6.5nm Baader filters perform on the Horsehead Nebula (Barnard 33) with my RASA 8?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis filter set is an ideal match for imaging the Horsehead Nebula with a RASA 8. The f\/2 focal ratio of the RASA is exactly what these filters are designed for. The \u003cstrong\u003e6.5nm H-alpha filter\u003c\/strong\u003e will provide excellent contrast to define the dark nebula against the glowing background of IC 434, capturing sharp detail with very short exposure times.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eAre these Baader f\/2 filters parfocal?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, Baader Planetarium engineers their CMOS-optimized filters to be parfocal. When you switch between the H-alpha, O-III, and S-II filters in this set, you should see minimal to no change in focus, saving valuable imaging time by eliminating the need to refocus with each filter change.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy would I choose a 6.5nm bandpass over a narrower 3nm filter for my f\/2 system?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFor an f\/2 system, a \u003cstrong\u003e6.5nm bandpass\u003c\/strong\u003e is often a better compromise. While a 3nm filter provides higher contrast, it's more sensitive to bandpass shift and collects photons more slowly. The 6.5nm width provides excellent contrast while maintaining a very high signal acquisition rate, which is the primary advantage of using an f\/2 astrograph.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Set\u003c\/td\u003e\n\u003ctd\u003eH-alpha, O-III, S-II\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandpass (FWHM)\u003c\/td\u003e\n\u003ctd\u003e6.5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptimized Focal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/2 to f\/3.5\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoatings\u003c\/td\u003e\n\u003ctd\u003eReflex-Blocker™, Life-Coat™\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCMOS Optimized\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, 31mm Unmounted, 36mm Unmounted, 50.4mm Unmounted, 50x50mm Unmounted, 65x65mm Unmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.02 (1.25\" Round Mounted)\u003cbr\u003e0.04 (2\" Round Mounted, 50.4mm Round Unmounted Filter)\u003cbr\u003e0.01 (31mm Round Unmounted Filter, 36mm Round Unmounted Filter)\u003cbr\u003e0.06 (50x50mm Square Filter)\u003cbr\u003e0.10 (65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter shape\u003c\/td\u003e\n\u003ctd\u003eround (1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted Filter, 50.4mm Round Unmounted Filter, 36mm Round Unmounted Filter)\u003cbr\u003esquare (50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter mounted\u003c\/td\u003e\n\u003ctd\u003eMounted (LPFC 6mm) (1.25\" Round Mounted, 2\" Round Mounted)\u003cbr\u003eUnmounted (31mm Round Unmounted Filter, 50.4mm Round Unmounted Filter, 50x50mm Square Filter, 36mm Round Unmounted Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eCMOS, CCD, H-alpha, O-III, S-II\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpecial Features\u003c\/td\u003e\n\u003ctd\u003eCMOS-optimized with Life-Coat™\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thickness (without cell)\u003c\/td\u003e\n\u003ctd\u003e2 mm (1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted Filter, 36mm Round Unmounted Filter)\u003cbr\u003e3 mm (50.4mm Round Unmounted Filter, 50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCWL (Central Wavelength)\u003c\/td\u003e\n\u003ctd\u003e656.3 nm \/ 500.7 nm \/ 671.7 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003eReflex-Blocker™ hard coated, planeoptically polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSuitable for f\/ratio\u003c\/td\u003e\n\u003ctd\u003ef\/3.4 and faster\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003cp\u003e\u003cem\u003eNote: This is a filter set containing three individual filters. Box contents may vary based on the specific size selected.\u003c\/em\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_Filter_Problems_FAQ_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium Filter Problems FAQ Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_Narrowband_Filters_on_Astronomical_Telescopes_Whitepaper.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium Narrowband Filters on Astronomical Telescopes Whitepaper\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/baader-planetarium-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eBaader Planetarium Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"1.25\" Round Mounted","offer_id":44967356989725,"sku":"BAA-2961660","price":656.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967357022493,"sku":"BAA-2961663","price":1079.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted Filter","offer_id":44967357055261,"sku":"BAA-2961661","price":696.0,"currency_code":"CAD","in_stock":true},{"title":"50.4mm Round Unmounted Filter","offer_id":44967357088029,"sku":"BAA-2961664","price":1127.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Filter","offer_id":44967357153565,"sku":"BAA-2961665","price":1298.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted Filter","offer_id":44967357186333,"sku":"BAA-2961662","price":775.0,"currency_code":"CAD","in_stock":true},{"title":"65x65mm Square Filter","offer_id":44967357219101,"sku":"BAA-2961666","price":1611.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader-f-2-Highspeed-Filter-Set-H-alpha-O-III-S-II-1__52568.1597110925.1280.1280.jpg?v=1684341313"},{"product_id":"baader-6-5nm-narrowband-filter-set-cmos-optimized-h-alpha-o-iii-s-ii","title":"Baader 6.5nm Narrowband Filter Set - CMOS-Optimized H-alpha\/O-III\/S-II","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e6.5nm Narrowband Filter Set for H-alpha, O-III, and S-II\u003c\/li\u003e\n\u003cli\u003eOptimized specifically for modern CMOS astronomy cameras\u003c\/li\u003e\n\u003cli\u003eReflex-Blocker™ coatings prevent halos and internal reflections\u003c\/li\u003e\n\u003cli\u003eLife-Coat™ sealed edges for enhanced durability and longevity\u003c\/li\u003e\n\u003cli\u003ePlaneoptically polished substrates ensure maximum image sharpness\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eBaader 6.5nm Narrowband Filter Set - CMOS-Optimized H-alpha\/O-III\/S-II\u003c\/h2\u003e\n\u003cp\u003eThe Baader 6.5nm Narrowband Filter Set is engineered for modern CMOS sensors, combining a tight 6.5nm bandpass with advanced coatings to isolate critical H-alpha, O-III, and S-II emission lines without generating artifacts. This 6.5nm design delivers high-contrast images by aggressively rejecting light pollution and moonlight, while the CMOS-optimization eliminates the halos around bright stars that plague filters not designed for highly reflective modern sensors.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eCMOS-Optimized Coatings: Suppressing Halos and Reflections\u003c\/h3\u003e\n\u003cp\u003eModern CMOS sensors are notoriously reflective compared to older CCD technology. Baader addresses this directly with advanced Reflex-Blocker™ coatings, which are specifically designed to neutralize reflections between the filter and the sensor. This technology effectively eliminates the halos and ghost images that can ruin an otherwise perfect exposure, even with very bright stars like Alnitak in the field of view.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe 6.5nm Bandpass: High Contrast for Nebula Imaging\u003c\/h3\u003e\n\u003cp\u003eThe 6.5nm full width at half maximum (FWHM) strikes a critical balance between contrast and signal strength. This bandpass is narrow enough to darken the sky background significantly and enhance faint nebular details, yet it remains efficient enough for use with a wide range of telescope focal ratios. It provides a substantial contrast boost over wider 7nm or 12nm filters without requiring the extremely long sub-exposures demanded by ultra-narrow 3nm designs.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eUncompromised Substrate and Life-Coat Durability\u003c\/h3\u003e\n\u003cp\u003eEach Baader filter is built on a planeoptically polished substrate, ensuring that it will not degrade the resolution of your optical system. The coatings are applied with Ion-Beam-Assisted Deposition (IBAD), resulting in a hard, scratch-resistant surface. Furthermore, Baader's proprietary Life-Coat™ process seals the coating edges, making them impervious to moisture and aging, guaranteeing the filter's transmission properties will not degrade over time.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eBaader 6.5nm CMOS vs. Traditional Narrowband Filters\u003c\/h3\u003e\n\u003cp\u003eOlder narrowband filters were designed for the less-reflective surfaces of CCD sensors. When used with a modern CMOS camera, these filters can produce prominent halos and reflections that are difficult to process out. The Baader CMOS-Optimized set solves this problem at the source.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBaader 6.5nm CMOS-Optimized:\u003c\/strong\u003e Features Reflex-Blocker™ coatings to absorb reflections between the filter and sensor, producing clean, halo-free stars. The coatings are also shifted to remain on-band even with fast optical systems down to f\/3.5.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTraditional Narrowband Filters:\u003c\/strong\u003e Lack specialized anti-reflection coatings for the camera side, leading to artifacts with reflective CMOS sensors. Their passbands can also shift significantly with fast focal ratios, reducing signal.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy are these Baader 6.5nm filters \"CMOS-Optimized\"?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThey are \"CMOS-Optimized\" because they feature Baader's proprietary \u003cstrong\u003eReflex-Blocker™ coatings\u003c\/strong\u003e. These coatings are specifically designed to prevent halos and internal reflections caused by the highly reflective nature of modern CMOS sensor assemblies. This results in cleaner images with higher contrast and no distracting artifacts around bright stars.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the advantage of a 6.5nm bandpass over a wider 7nm or 12nm filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA narrower bandpass like \u003cstrong\u003e6.5nm\u003c\/strong\u003e provides significantly higher contrast by rejecting more unwanted light from streetlights, moonlight, and natural skyglow. This makes faint nebula structures stand out more clearly against the background sky compared to wider filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Baader 6.5nm O-III filter perform on the Veil Nebula (NGC 6960) with a fast refractor?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eExcellent. The Veil Nebula is a strong O-III emitter, and the \u003cstrong\u003e6.5nm\u003c\/strong\u003e bandpass will produce extremely high contrast, revealing the delicate, filamentary structure of the supernova remnant. Baader's coatings are also designed to minimize band-shift with fast optics, ensuring you capture maximum signal even with a fast refractor.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eAre the filters in the Baader 6.5nm Narrowband Set parfocal?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, Baader manufactures these filters to be parfocal. All filters in the set are made with the same substrate thickness, meaning you should not need to refocus, or will only need a minimal adjustment, when switching between the H-alpha, O-III, and S-II filters. This is a major time-saver for automated imaging runs.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eI'm imaging the Heart Nebula (IC 1805) with my SCT at f\/7. Is 6.5nm a good choice?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, \u003cstrong\u003e6.5nm\u003c\/strong\u003e is an excellent choice for an f\/7 system. The Heart Nebula is rich in all three emission lines (H-alpha, O-III, and S-II). The 6.5nm bandpass will provide the contrast needed to separate the intricate structures within the nebula, and an f\/7 optical system is efficient enough to gather plenty of signal without requiring excessively long sub-exposures.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Baader 6.5nm H-alpha filter for solar viewing or imaging?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eAbsolutely not.\u003c\/strong\u003e These are deep-sky emission-line filters and are not safe for any kind of solar observation. Attempting to view the sun through this filter will cause immediate and permanent eye damage. For solar work, you must use a dedicated, certified solar filter designed for that purpose.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eNarrowband Emission Line (SHO)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandpass (FWHM)\u003c\/td\u003e\n\u003ctd\u003e6.5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWavelengths\u003c\/td\u003e\n\u003ctd\u003eH-alpha, O-III, S-II\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Feature\u003c\/td\u003e\n\u003ctd\u003eCMOS-Optimized with Reflex-Blocker™ Coatings\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDurability\u003c\/td\u003e\n\u003ctd\u003eLife-Coat™ Sealed Coating Edges\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Formats\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, 31mm Unmounted, 36mm Unmounted, 50.4mm Unmounted, 50x50mm Square, 65x65mm Square\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.02 (1.25\" Round Mounted)\u003cbr\u003e0.04 (2\" Round Mounted, 50.4mm Round Unmounted Filter)\u003cbr\u003e0.01 (36mm Round Unmounted Filter, 31mm Round Unmounted Filter)\u003cbr\u003e0.06 (50x50mm Square Filter)\u003cbr\u003e0.10 (65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter shape\u003c\/td\u003e\n\u003ctd\u003eround (1.25\" Round Mounted, 2\" Round Mounted, 36mm Round Unmounted Filter, 50.4mm Round Unmounted Filter, 31mm Round Unmounted Filter)\u003cbr\u003esquare (50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSingle or Set?\u003c\/td\u003e\n\u003ctd\u003eFilter-Set\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter mounted\u003c\/td\u003e\n\u003ctd\u003eMounted (LPFC 6mm) (1.25\" Round Mounted, 2\" Round Mounted)\u003cbr\u003eUnmounted (36mm Round Unmounted Filter, 50.4mm Round Unmounted Filter, 50x50mm Square Filter, 65x65mm Square Filter, 31mm Round Unmounted Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eCMOS, CCD, H-alpha, O-III, S-II\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpecial Features\u003c\/td\u003e\n\u003ctd\u003eCMOS-optimized with Life-Coat™\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thickness (without cell)\u003c\/td\u003e\n\u003ctd\u003e2 mm (1.25\" Round Mounted, 2\" Round Mounted, 36mm Round Unmounted Filter, 31mm Round Unmounted Filter)\u003cbr\u003e3 mm (50.4mm Round Unmounted Filter, 50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCWL (Central Wavelength)\u003c\/td\u003e\n\u003ctd\u003e656.3 nm \/ 500.7 nm \/ 671.7 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003eReflex-Blocker™ hard coated, planeoptically polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSuitable for f\/ratio\u003c\/td\u003e\n\u003ctd\u003e\u0026gt; f\/3.4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_Filter_Problems_FAQ_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium Filter Problems FAQ Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_Narrowband_Filters_on_Astronomical_Telescopes_Whitepaper.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium Narrowband Filters on Astronomical Telescopes Whitepaper\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/baader-planetarium-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eBaader Planetarium Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"1.25\" Round Mounted","offer_id":44967357808925,"sku":"BAA-2961650","price":609.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967357841693,"sku":"BAA-2961653","price":1031.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted Filter","offer_id":44967357874461,"sku":"BAA-2961652","price":728.0,"currency_code":"CAD","in_stock":true},{"title":"50.4mm Round Unmounted Filter","offer_id":44967357907229,"sku":"BAA-2961654","price":1174.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Filter","offer_id":44967357939997,"sku":"BAA-2961655","price":1251.0,"currency_code":"CAD","in_stock":true},{"title":"65x65mm Square Filter","offer_id":44967357972765,"sku":"BAA-2961656","price":1589.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted Filter","offer_id":44967358005533,"sku":"BAA-2961651","price":643.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Baader-Narrowband-Filter-Set-H-a-7nm-OIII-8-5nm-SII-8nm-1__77412.1597110943.1280.1280.jpg?v=1684341339"},{"product_id":"zwo-narrowband-filter-set-7nm-h-alpha-oiii-sii","title":"ZWO Narrowband Filter Set - 7nm H-alpha, OIII \u0026 SII","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eIncludes 1.25\" H-alpha, OIII, and SII filters\u003c\/li\u003e\n\u003cli\u003e7nm bandpass for high-contrast imaging\u003c\/li\u003e\n\u003cli\u003eIdeal for creating \"Hubble Palette\" images\u003c\/li\u003e\n\u003cli\u003eFine-optically polished to 1\/4 wave accuracy\u003c\/li\u003e\n\u003cli\u003eUp to 80% light transmission\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eZWO 1.25\" Narrowband Filter Set - 7nm H-alpha, OIII \u0026amp; SII\u003c\/h2\u003e\n\u003cp\u003eThe ZWO 1.25\" Narrowband Filter Set isolates the three most critical emission lines for deep-sky astrophotography with a tight 7nm bandpass. This set includes filters for Hydrogen-alpha (H-a) at 656nm, doubly-ionized Oxygen (OIII) at 500nm, and singly-ionized Sulfur (SII) at 672nm. Each filter is fine-optically polished to 1\/4 wave accuracy and features multi-layer anti-reflection coatings to achieve up to 80% light transmission, ensuring maximum signal reaches your monochrome camera sensor.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eIsolating Nebulosity with a 7nm Bandpass\u003c\/h3\u003e\n\u003cp\u003eA 7nm bandpass is the key to high-contrast nebula imaging, especially from light-polluted locations. By transmitting only a razor-thin slice of the spectrum around the target emission line, these filters reject broadband light from streetlights, moonlight, and the general skyglow background. The result is a dramatic increase in contrast, revealing faint, intricate structures in emission nebulae like the Veil Nebula (NGC 6960) or the Heart Nebula (IC 1805) that would be invisible in a standard LRGB image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eCreate Hubble Palette Images with 656nm, 500nm, and 672nm Filters\u003c\/h3\u003e\n\u003cp\u003eThis specific combination of H-a, OIII, and SII filters is the foundation of the iconic \"Hubble Palette.\" By mapping the data from each filter to a different color channel (typically SII to red, H-a to green, and OIII to blue), you can create vibrant, scientifically informative images that reveal the chemical composition of a nebula. The 672nm SII filter traces the coolest ionized gas, the 656nm H-a filter captures the most abundant hydrogen, and the 500nm OIII filter highlights the hottest, most energetic regions, giving your images incredible depth and color separation.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOptical Precision: 1\/4 Wave Polish and 80% Transmission\u003c\/h3\u003e\n\u003cp\u003eImage quality is maintained by polishing each filter to a 1\/4 wave standard, ensuring the wavefront from your telescope's optics passes through without distortion, preserving star sharpness. With light transmission peaking at 80% within the narrow 7nm bandpass, the filters capture a strong signal from nebulae without requiring excessively long sub-exposure times. This balance makes the ZWO 7nm set a highly efficient choice for capturing deep-sky data.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eZWO 7nm vs. Tighter 3nm Bandpass Filters\u003c\/h3\u003e\n\u003cp\u003eWhen choosing narrowband filters, a common question is the ideal bandpass. While more expensive 3nm filters offer slightly higher contrast and even better rejection of light pollution, the ZWO 7nm filters present a more practical starting point for many imagers.\n\u003c\/p\u003e\n\u003cul\u003e\n \u003cli\u003e\n\u003cstrong\u003eExposure Time:\u003c\/strong\u003e The 7nm bandpass allows more light through, enabling shorter sub-exposures to achieve a comparable signal-to-noise ratio. This is a significant advantage for those with entry-level mounts or limited imaging time.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003eSystem Compatibility:\u003c\/strong\u003e Tighter filters can sometimes introduce artifacts or be less effective with very fast optical systems (f\/4 and below) without careful setup. The 7nm bandpass is more forgiving across a wider range of telescope focal ratios.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003eCost-Effectiveness:\u003c\/strong\u003e For imagers moving from LRGB or one-shot color, the 7nm set delivers the vast majority of the benefits of narrowband imaging at a more accessible price point.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the ZWO 7nm Narrowband filter set with a color camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNarrowband filters are designed for \u003cstrong\u003emonochrome cameras\u003c\/strong\u003e. A color camera has a Bayer matrix (a grid of red, green, and blue filters) over its sensor. Using a narrowband filter, like H-alpha which is deep red, would only allow light to pass through the red pixels, wasting the signal from the green and blue pixels and resulting in a very inefficient, low-resolution image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the ZWO 7nm filters perform on the Orion Nebula (M42) from my backyard?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe ZWO 7nm filters will perform exceptionally well. M42 is extremely bright in both H-alpha and OIII. From a light-polluted backyard, these filters will darken the sky background significantly, allowing you to use longer exposures to capture the faint outer structures of the nebula without washing out the core. You will be able to resolve the intricate details within the Trapezium region with far more contrast than with standard LRGB filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat are the best deep-sky objects for this ZWO narrowband filter set?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis set is ideal for \u003cstrong\u003eemission nebulae\u003c\/strong\u003e, which are clouds of ionized gas. Excellent targets include:\n\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eNorth America Nebula (NGC 7000):\u003c\/strong\u003e Rich in H-alpha and SII.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVeil Nebula Complex (NGC 6960\/6992):\u003c\/strong\u003e A supernova remnant that glows brightly in H-alpha and OIII.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEagle Nebula (M16):\u003c\/strong\u003e Famous for the \"Pillars of Creation,\" which are stunning in the Hubble Palette.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeart and Soul Nebulae (IC 1805 \u0026amp; IC 1848):\u003c\/strong\u003e Large complexes that are perfect for wider-field scopes.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eGalaxies and reflection nebulae are not good targets for these filters as they emit broadband light.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo I need a filter wheel to use the ZWO 1.25\" filter set?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA filter wheel is the most convenient way to automate switching between the H-a, OIII, and SII filters during an imaging session. However, it is not strictly necessary. You can also use a manual filter drawer or a filter slider, which allows you to swap the 1.25\" threaded filters by hand between exposures.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the \"Hubble Palette\" and how do I create it with these ZWO filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Hubble Palette, also known as \"SHO,\" is a color mapping technique used to visualize the different gases in a nebula. After capturing separate images with each of the ZWO filters, you combine them in post-processing software like PixInsight or Photoshop. The standard mapping is:\n\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eS-II Data → Red Channel\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eH-a Data → Green Channel\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eO-III Data → Blue Channel\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThis creates the iconic gold-and-teal aesthetic seen in many images from the Hubble Space Telescope.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy would I choose this ZWO 7nm set over a more expensive 3nm set?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile 3nm filters offer the highest possible contrast, the 7nm set is often a better choice for practicality. The ZWO 7nm filters allow more light through, which means \u003cstrong\u003eshorter exposure times\u003c\/strong\u003e are needed to get a good signal. This is a major benefit if you have tracking limitations or less-than-perfect seeing conditions. They are also more affordable, providing an excellent entry into serious narrowband imaging.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSKU\u003c\/td\u003e\n\u003ctd\u003eZWO-NB7NMD1.25\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eProduct Type\u003c\/td\u003e\n\u003ctd\u003eFilter Set\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Class\u003c\/td\u003e\n\u003ctd\u003eNarrowband\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSize\u003c\/td\u003e\n\u003ctd\u003e31.75mm (1.25\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eShape\u003c\/td\u003e\n\u003ctd\u003eRound\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMounting Style\u003c\/td\u003e\n\u003ctd\u003eThreaded Cell\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandwidth\u003c\/td\u003e\n\u003ctd\u003e7 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003e1.25\" Mounted H-a 7nm Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003e1.25\" Mounted OIII 7nm Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003e1.25\" Mounted SII 7nm Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/zwo-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eZWO 2-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"ZWO","offers":[{"title":"1.25\" Round Mounted","offer_id":44967443366173,"sku":"ZWO-NB7nm1.25","price":517.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967443398941,"sku":"ZWO-NB7nm2","price":979.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967443464477,"sku":"ZWO-NB7nmD36","price":671.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/ZWO-Narrowband-Filter-Set-1-25-inch__67133.1596920829.1280.1280.jpg?v=1684342071"},{"product_id":"zwo-narrowband-h-alpha-filter-7nm","title":"ZWO Narrowband H-alpha Filter - 7nm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eIsolates Hydrogen-Alpha light at a 7nm bandpass\u003c\/li\u003e\n\u003cli\u003eStandard 1.25\" threaded metal cell\u003c\/li\u003e\n\u003cli\u003eBlocks light pollution and moonlight for extreme contrast\u003c\/li\u003e\n\u003cli\u003eMulti-layer anti-reflection coatings\u003c\/li\u003e\n\u003cli\u003eFine-optically polished to 1\/4 wave accuracy\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eZWO H-Alpha 7nm CCD Filter - 1.25\"\u003c\/h2\u003e\n\u003cp\u003eThe ZWO H-Alpha 7nm CCD Filter isolates the most important emission line in astrophotography within a tight 7nm bandpass, designed for standard 1.25\" filter wheels and camera nosepieces. This single-filter solution provides the highest contrast on emission nebulae for monochrome imaging setups and is protected by a 2-year warranty.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eIsolating Nebulae with a 7nm Bandpass\u003c\/h3\u003e\n\u003cp\u003eBy passing only a 7nm window of light centered on the 656nm Hydrogen-alpha wavelength, this ZWO filter creates a near-black sky background. This surgical isolation dramatically increases the contrast of emission nebulae like the Orion Nebula (M42) or the North American Nebula (NGC 7000), making their faint structures visible even under severe moonlight or urban light pollution.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOptical Precision at 1\/4 Wave\u003c\/h3\u003e\n\u003cp\u003eEach ZWO narrowband filter is fine-optically polished to a 1\/4 wave accuracy, ensuring that the filter itself does not degrade the sharpness of your optical train. Multi-layer anti-reflection coatings are applied to further suppress internal reflections, which prevents the halos and ghosting around bright stars that can compromise lesser filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eZWO 7nm vs. 3nm H-alpha Filters\u003c\/h3\u003e\n\u003cp\u003eChoosing a bandpass involves a direct trade-off between signal strength and contrast. While a 3nm filter provides the absolute highest contrast and rejection of light pollution, the ZWO 7nm filter captures more than twice the photons in the same exposure time. This makes the 7nm filter a more balanced choice for a wider range of targets and conditions.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eZWO 3nm H-alpha:\u003c\/strong\u003e Offers maximum contrast for extremely light-polluted skies or for resolving the finest filamentary details in bright nebulae like the Veil Nebula. Requires longer sub-exposure times.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eZWO 7nm H-alpha:\u003c\/strong\u003e Gathers signal faster, making it better suited for fainter nebulae, faster optical systems (f\/4-f\/7), or when you have limited imaging time. It still provides excellent contrast, far exceeding broadband filters.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eCompatibility with Any 1.25\" System\u003c\/h3\u003e\n\u003cp\u003eThe filter is mounted in a durable, threaded metal cell that conforms to the standard 1.25\" filter format. This ensures it will thread directly into any 1.25\" filter wheel, manual filter drawer, or camera nosepiece that accepts filters, providing a secure, tilt-free fit in your imaging train.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the ZWO H-alpha 7nm filter used for?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe ZWO H-alpha 7nm filter is designed for astrophotography with monochrome cameras. It isolates the specific wavelength of light emitted by ionized hydrogen (656nm), which is prevalent in star-forming regions and emission nebulae. This dramatically increases contrast and allows you to capture detailed images of nebulae, even from light-polluted locations.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the ZWO H-alpha 7nm filter with a color camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile you can, it's not ideal. A narrowband filter like this blocks almost all light except for a thin 7nm slice of deep red. A color camera's Bayer matrix has red, green, and blue pixels, so the green and blue pixels will receive no signal. You will get a monochrome red image with only 1\/4 of the camera's resolution. For color cameras, a multi-bandpass filter like the ZWO Duo-Band is a much more effective choice.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy choose a 7nm filter over a tighter 3nm ZWO filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe 7nm bandpass is a trade-off. It allows more light to reach the sensor than a 3nm filter, resulting in shorter exposure times to achieve the same signal level. This makes the 7nm filter more forgiving and efficient, especially on fainter objects or with slower telescopes. A 3nm filter offers higher contrast but requires significantly longer exposures.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the ZWO 7nm H-alpha filter perform on the Orion Nebula (M42) from the city?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt performs exceptionally well. The 7nm bandpass will reject the vast majority of urban light pollution (which is primarily broadband), darkening the sky background significantly. This will make the faint outer loops of M42 stand out clearly while preventing the bright core of the Trapezium from being completely blown out, allowing you to capture a much higher dynamic range image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat exposure times can I expect for the Cygnus Wall in NGC 7000 with this 7nm filter and an f\/5 refractor?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWith a typical monochrome CMOS camera (like a ZWO ASI294MM Pro) on an f\/5 refractor, you can expect to get a strong signal on the Cygnus Wall region of the North American Nebula (NGC 7000) with sub-exposures of 180 to 300 seconds. The 7nm bandpass allows for reasonably short exposures while still providing excellent contrast against the skyglow.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use this ZWO filter for viewing the Sun?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eAbsolutely not.\u003c\/strong\u003e This is an imaging filter for night-sky objects only. It is not a solar filter and provides no protection from harmful UV or infrared radiation. Attempting to view the sun with this filter will cause immediate and permanent eye damage and will destroy your camera sensor. Always use a certified solar filter that covers the entire front of your telescope for any solar observation.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSKU Number\u003c\/td\u003e\n\u003ctd\u003eZWO-Ha7NM1.25\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eH-Alpha\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Size\u003c\/td\u003e\n\u003ctd\u003e31.75mm (1.25\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandwidth\u003c\/td\u003e\n\u003ctd\u003e7 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Format\u003c\/td\u003e\n\u003ctd\u003eSingle Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eShape\u003c\/td\u003e\n\u003ctd\u003eRound\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMounting Style\u003c\/td\u003e\n\u003ctd\u003eThreaded Cell\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWarranty\u003c\/td\u003e\n\u003ctd\u003e2 Years\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003e1.25\" Mounted H-Alpha 7nm Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eProtective Plastic Case\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/www.zwoastro.com\/software\/\" target=\"_blank\"\u003e\u003csvg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 640 512\" class=\"DAV-img-box\"\u003e\u003cpath fill=\"#0047a7\" d=\"M128 32C92.7 32 64 60.7 64 96l0 256 64 0 0-256 384 0 0 256 64 0 0-256c0-35.3-28.7-64-64-64L128 32zM19.2 384C8.6 384 0 392.6 0 403.2C0 445.6 34.4 480 76.8 480l486.4 0c42.4 0 76.8-34.4 76.8-76.8c0-10.6-8.6-19.2-19.2-19.2L19.2 384z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e \n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eDownload ZWO Software\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/davidastro.com\/pages\/zwo-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eZWO 2-Year Limited Warranty\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"ZWO","offers":[{"title":"1.25\" Round Mounted","offer_id":44967443562781,"sku":"ZWO-Ha7nm1.25","price":181.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967443595549,"sku":"ZWO-Ha7nm2","price":349.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967443661085,"sku":"ZWO-Ha7nmD36","price":237.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/ZWO-H-alpha-Filter-1-25-inch__66275.1596920478.1280.1280.jpg?v=1684342084"},{"product_id":"zwo-narrowband-oiii-filter-7nm","title":"ZWO Narrowband OIII Filter - 7nm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e7nm Bandpass at OIII Emission Line\u003c\/li\u003e\n\u003cli\u003eIsolates Planetary Nebulae and Supernova Remnants\u003c\/li\u003e\n\u003cli\u003eStandard 1.25\" Threaded Filter Cell\u003c\/li\u003e\n\u003cli\u003e1\/4 Wave Optical Substrate Accuracy\u003c\/li\u003e\n\u003cli\u003eMulti-Layer Anti-Reflection Coatings\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eZWO OIII 7nm Narrowband Filter - 1.25\"\u003c\/h2\u003e\n\u003cp\u003eThe ZWO OIII 7nm 1.25\" Filter isolates the critical doubly-ionized oxygen emission line with a precise 7nm bandpass, dramatically increasing contrast on key deep-sky targets. Mounted in a standard 31.75mm threaded cell, its glass substrate is polished to an accuracy of 1\/4 wave to preserve the fine details resolved by your telescope.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eTargeting Emission Nebulae with a 7nm Bandpass\u003c\/h3\u003e\n\u003cp\u003eMost of the light from planetary nebulae and supernova remnants is emitted in the OIII line near 500nm. This ZWO filter uses a 7nm bandpass to reject broadband light pollution from city skies and unwanted starlight, making faint structures like the Veil Nebula (NGC 6960) or the Dumbbell Nebula (M27) stand out against a dark background. The 7nm window is wide enough to be effective with faster optical systems while still delivering a significant contrast boost.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e1\/4 Wave Optics for High-Resolution Imaging\u003c\/h3\u003e\n\u003cp\u003eA filter should only transmit light, not distort it. ZWO's narrowband filters are built on a fine-optically polished substrate with 1\/4 wave accuracy, ensuring the filter does not degrade the sharpness of your optical train. Multi-layer anti-reflection coatings maximize light transmission at the OIII wavelength and suppress internal reflections that can cause halos around bright stars.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eBuilding the Hubble Palette with a 1.25\" Filter\u003c\/h3\u003e\n\u003cp\u003eThe OIII filter is an essential component for creating tri-color \"Hubble Palette\" images when combined with H-alpha and SII filters. The standard 1.25\" (31.75mm) threaded cell is compatible with most astronomy cameras and filter wheels designed for smaller format sensors. While ideal for many setups, be aware that 1.25\" filters may introduce vignetting on cameras with APS-C or larger sensors, especially in fast f-ratio telescopes.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat types of objects are best for the ZWO OIII 7nm filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis filter excels at isolating structures in emission nebulae that are rich in doubly-ionized oxygen. Prime targets include \u003cstrong\u003eplanetary nebulae\u003c\/strong\u003e like the Ring Nebula (M57) and the Dumbbell Nebula (M27), and \u003cstrong\u003esupernova remnants\u003c\/strong\u003e such as the Veil Nebula (NGC 6960) and the Crab Nebula (M1).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the 7nm bandpass on the ZWO OIII filter compare to a 3nm or 5nm filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA \u003cstrong\u003e7nm bandpass\u003c\/strong\u003e offers a great balance between performance and flexibility. It provides a major contrast boost over a broadband filter but is more forgiving with faster focal ratio telescopes and allows for slightly shorter exposure times than tighter filters. A 3nm or 5nm filter will reject more light pollution and provide higher contrast on faint details, but typically requires longer exposures and performs best with slower optical systems.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill this 1.25\" ZWO OIII filter work with my full-frame camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt is not recommended. While the 1.25\" filter will thread into compatible nosepieces, it is too small to fully illuminate a full-frame sensor (or even most APS-C sensors) without significant vignetting, which appears as a darkening of the corners of the image. For larger sensors, a 2\" or larger filter is required to achieve an evenly illuminated field.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhen imaging the Veil Nebula (NGC 6960) with an 8\" SCT, is this ZWO OIII filter a good choice?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, it's an excellent choice. The Veil Nebula is extremely rich in OIII emission, and this filter will make its delicate, filamentary structure pop against the sky background. An 8\" SCT at f\/10 or f\/6.3 provides an ideal focal ratio for the 7nm bandpass, allowing you to capture high-contrast details in this classic supernova remnant.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the ZWO OIII 7nm filter for visual observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, narrowband filters can be used visually with great effect, especially on planetary nebulae. By threading the 1.25\" filter onto your eyepiece, you can dramatically increase the contrast of objects like the Ring Nebula (M57), often making it visible from suburban skies where it would otherwise be washed out.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I create a \"Hubble Palette\" image with this ZWO OIII filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eTo create a Hubble Palette (SHO) image, you need to capture data through three different narrowband filters:\n\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSulfur-II (SII):\u003c\/strong\u003e This data is typically mapped to the Red channel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHydrogen-alpha (H-alpha):\u003c\/strong\u003e This data is mapped to the Green channel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOxygen-III (OIII):\u003c\/strong\u003e This ZWO filter provides data for the Blue channel.\u003c\/li\u003e\n\u003c\/ul\u003e\nBy combining these three monochrome images in processing software, you create a false-color result that reveals intricate details and structure within the nebula.\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSKU\u003c\/td\u003e\n\u003ctd\u003eZWO-OIII7NM1.25\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eOIII (Oxygen-III) Narrowband\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFormat\u003c\/td\u003e\n\u003ctd\u003eSingle Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandpass\u003c\/td\u003e\n\u003ctd\u003e7 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSize\u003c\/td\u003e\n\u003ctd\u003e1.25\" (31.75mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMounting\u003c\/td\u003e\n\u003ctd\u003eThreaded Cell\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eShape\u003c\/td\u003e\n\u003ctd\u003eRound\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWarranty\u003c\/td\u003e\n\u003ctd\u003e2 Years\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eZWO 1.25\" Mounted OIII 7nm Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eProtective Plastic Case\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/zwo-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eZWO 2-Year Limited Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"ZWO","offers":[{"title":"1.25\" Round Mounted","offer_id":44967443726621,"sku":"ZWO-OIII7nm1.25","price":181.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967443759389,"sku":"ZWO-OIII7nm2","price":349.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967443824925,"sku":"ZWO-OIII7nmD36","price":237.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/ZWO-OIII-Filter-1-25-inch__00574.1596920412.1280.1280.jpg?v=1684342099"},{"product_id":"zwo-narrowband-sii-filter-7nm","title":"ZWO Narrowband SII Filter - 7nm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eIsolates the 672nm Sulfur-II emission line\u003c\/li\u003e\n\u003cli\u003e7nm bandpass for high-contrast imaging\u003c\/li\u003e\n\u003cli\u003eStandard 1.25\" threaded metal cell\u003c\/li\u003e\n\u003cli\u003e1\/4 wave polished substrate with multi-layer coatings\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eZWO SII 7nm 1.25\" Narrowband Filter\u003c\/h2\u003e\n\u003cp\u003eThe ZWO SII 7nm 1.25\" Filter isolates the deep-red Sulfur-II emission line centered at 672nm, a critical wavelength for mapping ionized structure in emission nebulae. Its tight 7nm bandpass dramatically increases contrast by rejecting light pollution and moonlight, while the 1\/4 wave polished substrate ensures that the finest details are not lost to optical imperfections.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eIsolating Deep-Red Structure with a 7nm Bandpass\u003c\/h3\u003e\n\u003cp\u003eBy restricting transmission to a narrow 7nm window around the 672nm SII line, this filter renders the sky background nearly black, causing faint nebulosity to stand out with striking clarity. This high signal-to-noise ratio is essential for revealing the delicate, wispy structures in supernova remnants like the Veil Nebula (NGC 6960) or the intricate star-forming regions within the Eagle Nebula (M16).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e1\/4 Wave Optics for High-Fidelity Imaging\u003c\/h3\u003e\n\u003cp\u003eEach ZWO narrowband filter is ground and polished to a 1\/4 wave surface accuracy, a specification that prevents distortion and maintains image sharpness across the field. Multiple layers of anti-reflection coatings are then applied to eliminate halos around bright stars and maximize light transmission within the 7nm bandpass, preserving the critical signal from your target.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eBuilding the Hubble Palette with the 1.25\" ZWO SII Filter\u003c\/h3\u003e\n\u003cp\u003eThis filter is the essential \"S\" component in the SHO color palette, made famous by images from the Hubble Space Telescope. When you combine data captured through this SII filter with separate exposures using Hydrogen-alpha and Oxygen-III filters, you can create stunning, scientifically valuable images that map the chemical composition of nebulae in vibrant gold, cyan, and blue hues. The standard 1.25\" threaded cell ensures compatibility with most filter wheels and camera nosepieces.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the primary purpose of the ZWO 7nm SII filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe ZWO 7nm SII filter is a narrowband filter designed for astrophotography with monochrome cameras. It isolates the 672nm wavelength of light emitted by ionized sulfur, which is crucial for capturing specific structural details in emission nebulae and creating \"Hubble Palette\" (SHO) images.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the ZWO 7nm SII filter with a color camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile technically possible, it is not recommended. Color cameras have a Bayer matrix (RGB filters) over their sensors, and only the red pixels will receive signal from the 672nm SII line. This results in a significant loss of signal and resolution, making a monochrome camera the superior choice for narrowband imaging.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the ZWO 7nm SII filter perform on the Rosette Nebula (NGC 2244) with a monochrome camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eOn a target like the Rosette Nebula, the ZWO 7nm SII filter excels at revealing the shock fronts and ionization structures that are less prominent in Hydrogen-alpha. It isolates the outer shell and filamentary details, providing the essential \"S\" channel data that adds depth and a golden hue to a final SHO composite image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat exposure times should I expect for the ZWO 7nm SII filter with an 8\" f\/4 Newtonian?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWith a fast f\/4 system, you can typically start with exposures of 300 to 600 seconds per sub-frame from a moderately light-polluted (Bortle 4-5) site. Sulfur-II is often the faintest of the three main narrowband channels (Ha, OIII, SII), so you may need to expose 1.5x to 2x longer for SII than you do for Hydrogen-alpha to achieve a comparable signal level.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is a 7nm bandpass important for the ZWO SII filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA narrower bandpass is more effective at rejecting unwanted light, such as from city glow, moonlight, and natural skyglow. The \u003cstrong\u003e7nm\u003c\/strong\u003e bandpass provides a very high-contrast view by darkening the sky background significantly, making it superior to wider 12nm or 15nm filters, especially from suburban locations.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the ZWO 7nm SII filter thread into a standard 1.25\" filter wheel?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The ZWO 7nm SII filter is mounted in a standard 1.25\" metal cell with M28.5x0.6 threads. It is fully compatible with any 1.25\" filter wheel, filter drawer, or accessory that accepts standard 1.25\" threaded filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSKU\u003c\/td\u003e\n\u003ctd\u003eZWO-SII7NM1.25\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eSulfur-II (SII) Narrowband\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandwidth\u003c\/td\u003e\n\u003ctd\u003e7 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSize\u003c\/td\u003e\n\u003ctd\u003e31.75mm (1.25\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMount Style\u003c\/td\u003e\n\u003ctd\u003eThreaded Cell\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eShape\u003c\/td\u003e\n\u003ctd\u003eRound\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCategory\u003c\/td\u003e\n\u003ctd\u003eSingle Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003e1.25\" Mounted Sulfur II 7nm Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eProtective Plastic Case\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/www.zwoastro.com\/software\/\" target=\"_blank\"\u003e\u003csvg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 640 512\" class=\"DAV-img-box\"\u003e\u003cpath fill=\"#0047a7\" d=\"M128 32C92.7 32 64 60.7 64 96l0 256 64 0 0-256 384 0 0 256 64 0 0-256c0-35.3-28.7-64-64-64L128 32zM19.2 384C8.6 384 0 392.6 0 403.2C0 445.6 34.4 480 76.8 480l486.4 0c42.4 0 76.8-34.4 76.8-76.8c0-10.6-8.6-19.2-19.2-19.2L19.2 384z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eDownload Software\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/zwo-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eZWO 2-Year Limited Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"ZWO","offers":[{"title":"1.25\" Round Mounted","offer_id":44967443857693,"sku":"ZWO-SII7nm1.25","price":181.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967443890461,"sku":"ZWO-SII7nm2","price":349.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967443955997,"sku":"ZWO-SII7nmD36","price":237.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/ZWO-SII-Filter-1-25-inch__61822.1596920329.1280.1280.jpg?v=1684342114"},{"product_id":"zwo-duo-band-filter","title":"ZWO Duo-Band Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003ePasses H-Alpha (15nm) and OIII (35nm) Wavelengths\u003c\/li\u003e\n\u003cli\u003eDesigned for One-Shot Color (OSC) Cameras\u003c\/li\u003e\n\u003cli\u003e1.25\" Threaded Cell\u003c\/li\u003e\n\u003cli\u003eOver 80% Ha \u0026amp; 90% OIII Transmission\u003c\/li\u003e\n\u003cli\u003e1\/4 Wavefront Polished Substrate\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eZWO 1.25\" Duo-Band Filter\u003c\/h2\u003e\n\u003cp\u003eThe ZWO 1.25\" Duo-Band Filter makes narrowband imaging possible for color cameras by isolating the two most critical emission nebula wavelengths. It captures H-Alpha (656.3 nm) in a 15 nm bandpass and OIII (500 nm) in a 35 nm bandpass, with transmission rates exceeding 80% and 90% respectively. This dual-band approach dramatically increases contrast on emission targets, allowing you to capture clean, detailed data from light-polluted locations with your existing one-shot color camera.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eCapture Narrowband Data with Your OSC Camera at Over 90% Transmission\u003c\/h3\u003e\n\u003cp\u003eThis filter is the most direct path to narrowband imaging for any astronomer with a color CMOS or CCD camera. By simultaneously passing both the deep red of Hydrogen-alpha and the teal-blue of Oxygen-III, it collects the primary structural and detail wavelengths of emission nebulae in a single exposure. This eliminates the need for a monochrome camera, filter wheel, and separate SHO filter set, significantly simplifying your imaging train and reducing total acquisition time.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e15nm Ha \u0026amp; 35nm OIII Bandpasses Optimized for Signal\u003c\/h3\u003e\n\u003cp\u003eThe ZWO Duo-Band filter features a 15 nm bandpass for H-Alpha and a wider 35 nm bandpass for OIII. This design is a deliberate trade-off, balancing interference rejection with the signal requirements of a color sensor's Bayer matrix. These wider-than-typical bandpasses allow more photons to reach the sensor, which is critical for achieving a strong signal-to-noise ratio with an OSC camera in reasonable exposure times, while still blocking the vast majority of light pollution from city lights and moonlight.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eZWO Duo-Band Filter vs. A Full Monochrome Setup\u003c\/h3\u003e\n\u003cp\u003eA dedicated monochrome camera with a filter wheel and 3nm or 5nm narrowband filters will always provide the highest possible resolution and data separation. That setup allows for precise control over each channel for complex Hubble Palette (SHO) processing. However, the ZWO Duo-Band Filter with a color camera grants access to high-contrast nebula imaging at a fraction of the cost, complexity, and setup time. For imagers in light-polluted skies who want to capture stunning nebulae without investing in a second complete imaging system, the Duo-Band filter is the more pragmatic solution.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e1\/4 Wavefront Optics \u0026amp; Anti-Reflection Build\u003c\/h3\u003e\n\u003cp\u003eEach Duo-Band filter is built on a Schott substrate, polished to a 1\/4 wavefront accuracy to ensure your telescope's resolution is not compromised. The 60\/40 surface quality meets MIL-O-13830 standards, and the filter cell itself is CNC machined from aircraft-grade aluminum. An anodized finish and internal extinction treatments prevent reflections and internal glare from degrading your final image, preserving the high contrast this filter is designed to create.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the ZWO Duo-Band Filter perform on the Orion Nebula (M42) with a color camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe ZWO Duo-Band filter is excellent for the Orion Nebula (M42). It will isolate the rich Hydrogen-alpha signal in the outer wings and the strong Oxygen-III emission in the Trapezium core. From a light-polluted site, this filter will dramatically darken the sky background, making the nebula's structure and color far more prominent than with a standard light pollution filter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I image galaxies like Andromeda (M31) with the ZWO Duo-Band Filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this filter is not recommended for broadband targets like galaxies or star clusters. Galaxies emit light across the entire visible spectrum. The Duo-Band filter blocks almost all of that light, passing only the H-alpha and OIII wavelengths. While you would capture the small emission nebulae within M31's arms, the galaxy's core and dust lanes would be almost completely filtered out. Use a broadband light pollution filter for galaxies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy are the H-Alpha (15nm) and OIII (35nm) bandpasses different widths on the ZWO Duo-Band Filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe different bandpass widths are an intentional design choice for use with one-shot color cameras. The wider \u003cstrong\u003e35 nm OIII bandpass\u003c\/strong\u003e allows more signal to pass through the Bayer matrix of the sensor, which is less sensitive to these wavelengths. The tighter \u003cstrong\u003e15 nm Ha bandpass\u003c\/strong\u003e provides higher contrast on the stronger hydrogen signal, balancing signal strength with rejection of nearby light pollution sources.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the ZWO Duo-Band Filter a good replacement for a monochrome camera setup?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt is an excellent alternative, but not a direct replacement. A monochrome camera with separate, very narrowband (e.g., 3nm) filters offers superior data isolation for advanced processing techniques like the Hubble Palette. The ZWO Duo-Band Filter provides a much simpler and more affordable way for OSC camera users to achieve the high-contrast results of narrowband imaging on emission nebulae, without the cost and complexity of a full mono system.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the 1.25\" ZWO Duo-Band filter work in my ZWO EFW filter wheel?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the ZWO 1.25\" Duo-Band Filter is threaded to mount directly into any ZWO electronic filter wheel (EFW) that accepts 1.25\" filters. It can also be threaded directly onto any 1.25\" nosepiece or accessory with standard filter threads.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does the 60\/40 surface quality specification mean for the ZWO Duo-Band Filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis specification refers to the optical polish and surface imperfections based on the MIL-O-13830 military standard. The \"60\" refers to the maximum allowable scratch width in microns, and the \"40\" refers to the maximum allowable dig or pit diameter in hundredths of a millimeter. A 60\/40 rating indicates a high-quality optical surface suitable for demanding imaging applications, ensuring minimal light scatter and preserved image contrast.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSKU\u003c\/td\u003e\n\u003ctd\u003eZWO-DB1.25\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eDual Narrowband Pass (Ha, OIII)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSize\u003c\/td\u003e\n\u003ctd\u003e1.25\" (31.75mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMounting\u003c\/td\u003e\n\u003ctd\u003eThreaded Cell\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-Alpha Bandpass\u003c\/td\u003e\n\u003ctd\u003e15 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOIII Bandpass\u003c\/td\u003e\n\u003ctd\u003e35 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-Alpha Transmission\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;80% at 656.3 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOIII Transmission\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;90% at 486nm, 496nm, and 501nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWavefront Accuracy\u003c\/td\u003e\n\u003ctd\u003e1\/4 Wavefront\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eSchott Glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eThickness\u003c\/td\u003e\n\u003ctd\u003e1.85 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40 (per MIL-O-13830)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eShape\u003c\/td\u003e\n\u003ctd\u003eRound\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eZWO 1.25\" Duo-Band Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/www.zwoastro.com\/software\/\" target=\"_blank\"\u003e\u003csvg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 640 512\" class=\"DAV-img-box\"\u003e\u003cpath fill=\"#0047a7\" d=\"M128 32C92.7 32 64 60.7 64 96l0 256 64 0 0-256 384 0 0 256 64 0 0-256c0-35.3-28.7-64-64-64L128 32zM19.2 384C8.6 384 0 392.6 0 403.2C0 445.6 34.4 480 76.8 480l486.4 0c42.4 0 76.8-34.4 76.8-76.8c0-10.6-8.6-19.2-19.2-19.2L19.2 384z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e \n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eDownload Software\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/zwo-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eZWO 2-Year Limited Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"ZWO","offers":[{"title":"1.25\" Round Mounted","offer_id":44967448379677,"sku":"ZWO-DB1.25","price":139.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967448412445,"sku":"ZWO-DB2","price":239.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/ZWO-Duo-Band-Filter-1__12335.1596910054.1280.1280.jpg?v=1684342173"},{"product_id":"astrodon-h-alpha-filter-5nm","title":"Astrodon H-alpha Filter - 5nm","description":"\u003c!-- more --\u003e\u003cp\u003eH-α (hydrogen-alpha) at 656 nm (nanometers) is deep red in color and the most popular narrowband filter. Hydrogen is ubiquitous in the cosmos and is present in emission nebula (North American, Pelican), planetary nebula (Dumbbell, Ring), Wolf-Rayet objects (Crescent, Thor’s Helmet) and supernova remnants (Veil). Many imagers like to present just a black-and-white H-α image of an object. It is has a beauty all by itself, like an Ansel Adams photo. However, most imagers blend their H-α data into their red RGB data to enhance structural detail while maintaining a “natural” look. Therefore, the H-α filter should be your first narrowband addition to your LRGB filters. The basic imaging set of 5 filters becomes LRGBH-α.\u003c\/p\u003e\u003cp\u003eAstrodon H-α filters have a center bandwidth of 656.3 nm.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eAstrodon Narrowband\u003c\/strong\u003e filters set a new bar of performance and durability for imaging and research. The narrow 5 and 3 nm bandwidths enhance contrast of emission targets by lowering your background signal. The guaranteed \u0026gt;90% transmittance at the emission wavelength provides you with the highest signal available. This guaranty is expensive to manufacture for such spectrally narrow filters, but it assures you in writing on each filter box that you will get what you paid for. These two factors combine to provide you with the highest contrast available. Our latest narrowband filters are typically achieving \u0026gt;95-98% transmittance. Astrodon Narrowband filters are renowned for minimizing halos around bright stars, even for long exposures of 30-45 minutes typical of narrowband imaging in astrophotography. Lastly, Astrodon Narrowband filters are coated to the edge of the part and are edge blackened. This is critical to minimize stray light for a filter that blocks most light except for the narrow bandpass.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eAstrodon Narrowband\u003c\/strong\u003e filters for imaging are all about contrast. What do we mean by this? Contrast brings out faint features by reducing the background – the narrower the filter, the better. The problem is keeping the signal (%T at the emission line) constant as the filter becomes spectrally narrower. This is why our \u0026gt;90%T guarantee is so important, even though it becomes very costly to manufacture. But, this assures you that you can take advantage of the improved contrast with our narrower filters compared to the much less expensive 7- 8.5 nm filters on the market. You can see the increase in contrast in the sequence of equal-exposure images of the Crescent Nebula (NGC 6888) taken on the same system and on the same night. As the bandwidth becomes narrower, the nebula “pops” out of the background, as does the faint surrounding nebulosity. Actually, the \u0026gt;90%T is a legacy specification, since new production technologies employed over the past 3-4 years routinely produces 97-98%T at the emission wavelengths.\u003c\/p\u003e\u003cp\u003eRandom tests of a competitor’s low-cost 7 nm H-a filter showed %T values ranging from 86% down to 71%. Random selection of 5 nm Astrodon filters measured %T values at the H-a emission wavelength of 93, 98, 97 and 98%. You will never know that you are using their 71% filter compared to a 97% Astrodon filter because they do not guarantee this important performance parameter. They recently came out with a 3.5 nm H-a narrowband filter and those results are even worse, ranging from 3-70% at the emission wavelength. Similarly, analysis of different 2016 lots of Astrodon 3 nm H-a filters measured 97, 97, 97 and 96%T. Yes, our filters are more expensive, but you always know what you are getting with Astrodon Narrowband filters – the best performance in the market – guaranteed. Our recent blueshift data show that Astrodon 3 and 5 nm filters can be used with nearly all systems as fast as f\/3.5 with virtually no loss in emission signal, so you do not need to buy custom “upshifted” filters if you have both fast and slow systems.\u003c\/p\u003e\u003cp\u003eStep up to the quality and performance of Astrodon narrowband filters.\u003c\/p\u003e\u003cdiv data-custom-tab\u003e\n\u003cp data-custom-tab-title\u003eDownloads\u003c\/p\u003e\n\u003cdiv\u003e\n\u003cp\u003e\u003ca title=\"Astrodon Narrowband Filter Scans\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/t\/6\/assets\/description_image_Astrodon_Narrowband_Filter_Scans.pdf?v=1684343277\" target=\"_blank\" rel=\"noopener\"\u003eAstrodon Narrowband Filter Scans\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003e\u003ca title=\"Astrodon Narrowband Filter Comparison\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/t\/6\/assets\/description_image_Astrodon_Sloan_Filter_Comparison.pdf?v=1684343253\" target=\"_blank\" rel=\"noopener\"\u003eAstrodon Narrowband Filter Comparison\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003e\u003ca title=\"Astrodon Narrowband FAQ\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/t\/6\/assets\/description_image_Astrodon_Narrowband_FAQ.pdf?v=1684343280\" target=\"_blank\" rel=\"noopener\"\u003eAstrodon Narrowband FAQ\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003e\u003ca title=\"Narrowband Presentation\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/t\/6\/assets\/description_image_Astrodon_Narrowband_Presentation.pdf?v=1684343287\" target=\"_blank\" rel=\"noopener\"\u003eNarrowband Presentation\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Astrodon","offers":[{"title":"31mm Round Mounted","offer_id":44967516045597,"sku":"DON-HA5_31R","price":300.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Astrodon-H-Alpha-Filter-1-25-inch__47154.1597719754.1280.1280.jpg?v=1684343307"},{"product_id":"astrodon-sii-filter-5nm","title":"Astrodon SII Filter - 5nm","description":"\u003c!-- more --\u003e\u003cp\u003eIf you want the look of Hubble Space Telescope (HST) images, such as the famous “Pillars of Creation” (the Eagle Nebula, Messier 16), then the next filter to consider adding to your collection after H-a and OIII is the SII (es-two) or sulfur filter. The SII filter, like H-a, is a deep red filter near 672 nm. H-a, OIII and SII filters provide that Hubble look for many emission nebula. Again, tri-color narrowband imaging with these three filters can be done with the moon up, so your equipment is not sitting dormant for several weeks.\u003c\/p\u003e\u003cp\u003eAstrodon SII filters have a center bandwidth of 671.6nm\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eAstrodon Narrowband\u003c\/strong\u003e filters set a new bar of performance and durability for imaging and research. The narrow 5 and 3 nm bandwidths enhance contrast of emission targets by lowering your background signal. The guaranteed \u0026gt;90% transmittance at the emission wavelength provides you with the highest signal available. This guaranty is expensive to manufacture for such spectrally narrow filters, but it assures you in writing on each filter box that you will get what you paid for. These two factors combine to provide you with the highest contrast available. Our latest narrowband filters are typically achieving \u0026gt;95-98% transmittance. Astrodon Narrowband filters are renowned for minimizing halos around bright stars, even for long exposures of 30-45 minutes typical of narrowband imaging in astrophotography. Lastly, Astrodon Narrowband filters are coated to the edge of the part and are edge blackened. This is critical to minimize stray light for a filter that blocks most light except for the narrow bandpass.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eAstrodon Narrowband\u003c\/strong\u003e filters for imaging are all about contrast. What do we mean by this? Contrast brings out faint features by reducing the background – the narrower the filter, the better. The problem is keeping the signal (%T at the emission line) constant as the filter becomes spectrally narrower. This is why our \u0026gt;90%T guarantee is so important, even though it becomes very costly to manufacture. But, this assures you that you can take advantage of the improved contrast with our narrower filters compared to the much less expensive 7- 8.5 nm filters on the market. You can see the increase in contrast in the sequence of equal-exposure images of the Crescent Nebula (NGC 6888) taken on the same system and on the same night. As the bandwidth becomes narrower, the nebula “pops” out of the background, as does the faint surrounding nebulosity. Actually, the \u0026gt;90%T is a legacy specification, since new production technologies employed over the past 3-4 years routinely produces 97-98%T at the emission wavelengths.\u003c\/p\u003e\u003cp\u003eRandom tests of a competitor’s low-cost 7 nm H-a filter showed %T values ranging from 86% down to 71%. Random selection of 5 nm Astrodon filters measured %T values at the H-a emission wavelength of 93, 98, 97 and 98%. You will never know that you are using their 71% filter compared to a 97% Astrodon filter because they do not guarantee this important performance parameter. They recently came out with a 3.5 nm H-a narrowband filter and those results are even worse, ranging from 3-70% at the emission wavelength. Similarly, analysis of different 2016 lots of Astrodon 3 nm H-a filters measured 97, 97, 97 and 96%T. Yes, our filters are more expensive, but you always know what you are getting with Astrodon Narrowband filters – the best performance in the market – guaranteed. Our recent blueshift data show that Astrodon 3 and 5 nm filters can be used with nearly all systems as fast as f\/3.5 with virtually no loss in emission signal, so you do not need to buy custom “upshifted” filters if you have both fast and slow systems.\u003c\/p\u003e\u003cp\u003eStep up to the quality and performance of Astrodon narrowband filters.\u003c\/p\u003e\u003cdiv data-custom-tab\u003e\n\u003cp data-custom-tab-title\u003eDownloads\u003c\/p\u003e\n\u003cdiv\u003e\n\u003cp\u003e\u003ca title=\"Astrodon Narrowband Filter Scans\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/t\/6\/assets\/description_image_Astrodon_Narrowband_Filter_Scans.pdf?v=1684343277\" target=\"_blank\" rel=\"noopener\"\u003eAstrodon Narrowband Filter Scans\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003e\u003ca title=\"Astrodon Narrowband Filter Comparison\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/t\/6\/assets\/description_image_Astrodon_Sloan_Filter_Comparison.pdf?v=1684343253\" target=\"_blank\" rel=\"noopener\"\u003eAstrodon Narrowband Filter Comparison\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003e\u003ca title=\"Astrodon Narrowband FAQ\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/t\/6\/assets\/description_image_Astrodon_Narrowband_FAQ.pdf?v=1684343280\" target=\"_blank\" rel=\"noopener\"\u003eAstrodon Narrowband FAQ\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003e\u003ca title=\"Narrowband Presentation\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/t\/6\/assets\/description_image_Astrodon_Narrowband_Presentation.pdf?v=1684343287\" target=\"_blank\" rel=\"noopener\"\u003eNarrowband Presentation\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Astrodon","offers":[{"title":"31mm Round Mounted","offer_id":44967520862493,"sku":"DON-SII5_31R","price":300.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Astrodon-SII-Filter-31mm__96921.1597720239.1280.1280.jpg?v=1684343371"},{"product_id":"optolong-l-enhance-filter","title":"Optolong L-Enhance Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDual-bandpass filter isolates H-Alpha, H-Beta, and OIII emission lines\u003c\/li\u003e\n\u003cli\u003ePeak transmission of over 90% for maximum signal\u003c\/li\u003e\n\u003cli\u003eBlocks over 99% of light pollution across a 300-1000nm range\u003c\/li\u003e\n\u003cli\u003eMaintains image sharpness with a λ\/4 transmitted wavefront\u003c\/li\u003e\n\u003cli\u003eConstructed from 1.85mm thick B270 optical glass\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong L-Enhance Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong L-Enhance filter is an economical, high-transmission solution for color astrophotography from light-polluted skies. This dual-bandpass filter achieves over 90% peak transmission in the critical H-Alpha, H-Beta, and Oxygen III emission lines, capturing the most important nebula data with any color camera. It simultaneously eliminates the impact of urban skyglow by blocking more than 99% of light pollution lines across a wide 300-1000nm range. The entire optical path is built on a 1.85mm B270 substrate polished to a λ\/4 transmitted wavefront, ensuring your telescope's resolution is perfectly preserved.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eDual-Bandpass Design: Over 90% Transmission in H-Alpha, H-Beta \u0026amp; OIII\u003c\/h3\u003e\n\u003cp\u003eUnlike broadband filters that pass large sections of the spectrum, the L-Enhance isolates only the most important wavelengths for emission nebulae. By targeting H-Alpha (656nm), H-Beta (486nm), and OIII (500nm) with a peak transmission greater than 90%, it dramatically increases the contrast between your target and the sky background. This design choice prioritizes the wavelengths associated with hydrogen and oxygen—the building blocks of star formation—to deliver scientifically significant data from your color camera in a single shot.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eLight Pollution Suppression: \u0026gt;99% Rejection of Unwanted City Glow\u003c\/h3\u003e\n\u003cp\u003eFor imagers in urban or suburban locations, the primary challenge is skyglow from artificial lighting. The L-Enhance filter meets this challenge with an aggressive blocking depth of over 99% for major light pollution sources, including mercury and sodium vapor lamps. This deep blocking darkens the sky background in your images, allowing the faint, desirable light from nebulae to stand out clearly. The result is longer possible sub-exposure times and a signal-to-noise ratio that was previously only achievable from dark sites.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOptical \u0026amp; Build Quality: λ\/4 Wavefront on a 1.85mm B270 Substrate\u003c\/h3\u003e\n\u003cp\u003eA filter should only transmit light, not distort it. The Optolong L-Enhance is built on a 1.85mm thick B270 glass substrate, polished to a surface quality of 60\/40 and a parallelism of 30 arcseconds. Critically, it guarantees a transmitted wavefront of λ\/4 or better, ensuring that it will not introduce aberrations or degrade the sharp stars produced by your telescope's optics. Advanced ion-assisted deposition coatings ensure these transmission characteristics are durable, scratch-resistant, and stable regardless of temperature changes during an imaging session.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe 1-Shot-Color Solution: L-Enhance vs. Monochrome Narrowband\u003c\/h3\u003e\n\u003cp\u003eWhile a monochrome camera with a filter wheel and separate S-II, H-Alpha, and O-III filters offers maximum data control, this approach is complex and expensive. The Optolong L-Enhance provides a streamlined and highly effective alternative for one-shot-color (OSC) cameras like DSLRs and dedicated astronomy CMOS cameras.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eEfficiency:\u003c\/strong\u003e The L-Enhance captures two of the most important bandpasses (H-Alpha and OIII) simultaneously, dramatically reducing the total imaging time required compared to shooting each channel separately with a mono camera.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSimplicity:\u003c\/strong\u003e It eliminates the need for a filter wheel and the complexities of combining multiple monochrome datasets, making deep-sky imaging more accessible.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCost-Effectiveness:\u003c\/strong\u003e For a fraction of the cost of a full monochrome setup, the L-Enhance unlocks the ability to shoot high-contrast nebula images from the city.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat makes the Optolong L-Enhance different from a standard light pollution filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA standard light pollution (LPS) filter is a \u003cstrong\u003ebroadband\u003c\/strong\u003e filter that tries to notch out specific light pollution lines while passing most other light. The Optolong L-Enhance is a \u003cstrong\u003emulti-bandpass narrowband\u003c\/strong\u003e filter. It works in reverse: it blocks almost the entire spectrum, only passing specific, narrow bands corresponding to nebula emission lines (H-Alpha, H-Beta, and OIII), resulting in much higher contrast.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong L-Enhance filter with a monochrome camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, you can. While designed for color cameras, the L-Enhance works well with a monochrome camera to capture H-Alpha, H-Beta, and OIII data simultaneously for a high-quality luminance frame. This is useful for simplifying data acquisition, though you will not be able to separate the individual channels for color mapping as you would with dedicated single-bandpass filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong L-Enhance perform on a target like the North America Nebula (NGC 7000) from the suburbs?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Optolong L-Enhance is exceptionally effective on emission nebulae like the North America Nebula (NGC 7000) and the nearby Pelican Nebula (IC 5070). These targets are rich in Hydrogen-Alpha, which the filter passes with over 90% transmission. From a suburban location, the filter's \u0026gt;99% blocking of skyglow will darken the background, revealing the intricate structures and faint extensions of the nebula that would otherwise be lost.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong L-Enhance effective for imaging the Veil Nebula complex under moonlight?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. Moonlight is broadband light, and a narrowband filter like the L-Enhance is the best tool for mitigating its effects. Because the filter only passes the narrow bands of OIII and H-Alpha\/H-Beta, it blocks the vast majority of moonlight. This allows you to continue imaging targets rich in those emissions, like the Veil Nebula, even during bright moonlit nights.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy does the Optolong L-Enhance pass H-Beta in addition to H-Alpha and OIII?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe H-Beta emission line (486nm) is very close to the OIII lines (~500nm). The L-Enhance is designed with a wider bandpass in the blue-green part of the spectrum that includes both OIII and H-Beta. This captures more signal from objects that have strong H-Beta emission, such as the California Nebula or Horsehead Nebula, adding to the richness of the final image from a color camera.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill I need to refocus when using the 1.85mm Optolong L-Enhance filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, adding any filter into the optical path will shift the focus point. The 1.85mm thickness of the B270 glass will require a small amount of outward focus travel. It is always recommended to check and readjust focus after inserting or removing a filter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Material\u003c\/td\u003e\n\u003ctd\u003eB270\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Thickness\u003c\/td\u003e\n\u003ctd\u003e1.85mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePeak Transmission\u003c\/td\u003e\n\u003ctd\u003eT\u0026gt;90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Range\u003c\/td\u003e\n\u003ctd\u003e300-1000nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Depth\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;99% at light pollution lines\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront\u003c\/td\u003e\n\u003ctd\u003eλ\/4 RMS\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30s\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, Clip for Canon EOS APS-C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":44967781531933,"sku":"OPT-13801","price":251.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":44967781564701,"sku":"OPT-13802","price":321.0,"currency_code":"CAD","in_stock":true},{"title":"Clip for Canon EOS APS-C","offer_id":44967781597469,"sku":"OPT-13804","price":363.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Optolong-L-Enhance-2inch__85261.1612894707.1280.1280.jpg?v=1684345842"},{"product_id":"optolong-l-extreme-filter","title":"Optolong L-Extreme Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eNarrow dual-bandpass filter for H-Alpha and OIII\u003c\/li\u003e\n\u003cli\u003eBlocks \u0026gt;99% of light pollution emission lines\u003c\/li\u003e\n\u003cli\u003ePeak transmission of \u0026gt;90% at critical wavelengths\u003c\/li\u003e\n\u003cli\u003eTransmitted Wavefront RMS of λ\/4\u003c\/li\u003e\n\u003cli\u003e1.85mm thick B270 substrate with 30s parallelism\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong L-Extreme Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong L-Extreme Filter isolates critical nebula emission lines with over 90% peak transmission while blocking more than 99% of common light pollution sources. Built on a 1.85mm B270 substrate, its λ\/4 transmitted wavefront and 30s parallelism ensure your optical system's native resolution is maintained. This narrow dual-band design simultaneously captures H-alpha and Oxygen III, maximizing contrast for one-shot color and monochrome cameras operating under bright urban skies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eA Dual-Band Design for \u0026gt;99% Light Pollution Suppression\u003c\/h3\u003e\n\u003cp\u003eThe L-eXtreme isolates the two most important emission lines for most nebulae—Hydrogen-alpha and Oxygen III—on a single filter. By aggressively blocking wavelengths outside these passbands, including a \u0026gt;99% rejection of artificial light pollution, the filter produces a dramatic increase in contrast between your target and the skyglow background. This allows you to capture clean, detailed data even from severely light-polluted locations or during bright moonlit nights.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOptimized for Fast Optics and One-Shot Color Cameras\u003c\/h3\u003e\n\u003cp\u003eModern fast optical systems, such as f\/2 RASA or HyperStar setups, place high demands on filter performance. The L-eXtreme is engineered to minimize band-shift with these steep light cones, ensuring consistent transmission and color balance. For imagers using one-shot color cameras like DSLRs or dedicated CMOS astronomy cameras, this filter is a cost-effective and convenient way to produce detailed bicolor images without the need for a filter wheel and monochrome setup.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eλ\/4 Wavefront Accuracy and Durable Ion-Assisted Coatings\u003c\/h3\u003e\n\u003cp\u003eA filter should never degrade the quality of your telescope's optics. The L-eXtreme is manufactured to strict tolerances, with a transmitted wavefront of λ\/4 and parallelism of 30 arcseconds, preventing any introduction of aberrations or distorted star shapes. The multi-layer coatings are applied using an advanced ion-assisted deposition process, creating a durable, scratch-resistant surface that provides wavelength stability regardless of temperature changes during an imaging session.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOptolong L-eXtreme vs. L-eNhance: The Tri-Band Trade-Off\u003c\/h3\u003e\n\u003cp\u003eThe primary difference lies in their bandpass strategy. The L-eNhance is a tri-band filter, passing H-alpha, OIII, and H-beta. The L-eXtreme is a dual-band filter, passing only H-alpha and OIII.\u003c\/p\u003e\n\u003cp\u003eThe L-eXtreme's advantage is its complete rejection of the wavelengths between the H-beta and OIII lines. This region contains no significant nebula emission but is a source of urban light pollution. By blocking it, the L-eXtreme delivers a darker sky background and higher overall contrast on most targets, making it the superior choice for maximum signal-to-noise ratio in heavy light pollution.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat makes the Optolong L-eXtreme different from the L-eNhance filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003eOptolong L-eXtreme\u003c\/strong\u003e is a dual-band filter that isolates the H-alpha and OIII emission lines. The L-eNhance is a tri-band filter that also includes H-beta. The L-eXtreme provides higher contrast and darker skies by blocking the light pollution between the H-beta and OIII lines, a region with no major nebula emissions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong L-eXtreme filter with my DSLR camera in the city?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. The L-eXtreme is designed specifically for this purpose. It works exceptionally well with one-shot color cameras like DSLRs and dedicated astronomy cameras, allowing you to capture high-contrast images of emission nebulae despite heavy urban light pollution.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong L-eXtreme perform on the Orion Nebula (M42) from a light-polluted suburb?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe L-eXtreme is an excellent choice for the Orion Nebula (M42). It will dramatically darken the sky background, enhancing the faint, extended nebulosity while preserving the natural colors of the hydrogen (red) and oxygen (teal) regions. You will be able to capture significantly more detail in the nebula's structure than you could without a filter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong L-eXtreme suitable for fast telescopes like a RASA or HyperStar system?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the L-eXtreme is well-suited for fast optical systems. Its coatings are designed to minimize the band-shift effects that can occur with steep light cones (low f-ratios), ensuring reliable performance and color balance even at f\/2.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the L-eXtreme filter work for monochrome cameras?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile designed with one-shot color cameras in mind, the L-eXtreme can be used effectively with monochrome cameras. It allows you to capture H-alpha and OIII data simultaneously. For serious monochrome imaging, separate narrowband filters for Ha, OIII, and SII will offer more control, but the L-eXtreme provides a convenient way to gather data for a bicolor Hubble-palette style image in less time.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy doesn't the Optolong L-eXtreme pass H-beta light?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis is a deliberate design choice to maximize contrast. While a few nebulae, like the Horsehead Nebula (Barnard 33), have a notable H-beta signal, most emission nebulae are dominated by H-alpha and OIII. By blocking the H-beta line and the region between it and OIII, the L-eXtreme eliminates more light pollution, leading to a better signal-to-noise ratio on the vast majority of targets.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eB270\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eThickness\u003c\/td\u003e\n\u003ctd\u003e1.85mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePeak Transmission\u003c\/td\u003e\n\u003ctd\u003eT\u0026gt;90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Range\u003c\/td\u003e\n\u003ctd\u003e300-1000nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Depth\u003c\/td\u003e\n\u003ctd\u003eLight pollution line blocking \u0026gt;99%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront RMS\u003c\/td\u003e\n\u003ctd\u003eλ\/4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30s\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":44967910277405,"sku":"OPT-13901","price":335.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":44967910310173,"sku":"OPT-13902","price":432.0,"currency_code":"CAD","in_stock":true},{"title":"Clip for Nikon Z Full Frame","offer_id":52942348550429,"sku":"OPT-LEXTREME-NK-Z","price":363.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Optolong-L-Enhance__74495.1625788241.1280.1280.jpg?v=1684346873"},{"product_id":"baader-3-5-4nm-f-2-ultra-highspeed-filter-set-cmos-optimized-h-alpha-o-iii-s-ii","title":"Baader 3.5\/4nm f\/2 Ultra-Highspeed Filter Set - CMOS-Optimized H-alpha\/O-III\/S-II","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e3.5nm (H-alpha, S-II) and 4nm (O-III) Bandpasses\u003c\/li\u003e\n\u003cli\u003eOptimized for f\/2 Ultra-Highspeed Optical Systems\u003c\/li\u003e\n\u003cli\u003eCMOS-Optimized with Reflex-Blocker™ Coatings\u003c\/li\u003e\n\u003cli\u003ePre-Shifted Center Wavelengths to Counteract Band-Shift\u003c\/li\u003e\n\u003cli\u003eLife-Coat™ Hard Coatings for Extreme Durability\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section-center\"\u003e\n      \u003ch2\u003eBaader 3.5\/4nm f\/2 Ultra-Highspeed Filter Set - CMOS-Optimized H-alpha\/O-III\/S-II\u003c\/h2\u003e\n      \u003cp\u003eThe Baader 3.5\/4nm f\/2 Ultra-Highspeed Filter Set is engineered specifically for modern, fast astrographs like Celestron RASA and HyperStar systems. This CMOS-optimized trio features ultra-narrow 3.5nm H-alpha and S-II filters and a 4nm O-III filter, all pre-shifted to place their transmission peaks precisely on the emission line when used in an f\/2 light cone. This design corrects for the inherent blue-shift that occurs with fast optics, ensuring you capture maximum signal without the transmission loss typical of standard narrowband filters on systems faster than f\/3.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eEngineered for f\/2 Systems: Pre-Shifted for Maximum Signal\u003c\/h3\u003e\n      \u003cp\u003eStandard narrowband filters suffer from band-shift when used in optical systems faster than f\/4; the steep light cone shifts the filter's transmission curve toward blue, causing it to miss the target emission line. Baader's f\/2 Ultra-Highspeed filters solve this by intentionally shifting the center wavelength during manufacturing. This ensures that at f\/2, the filter's passband is perfectly centered on the 656.3nm, 500.7nm, or 672.4nm lines, delivering nearly 100% of the available signal to your sensor.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n    \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eCMOS-Optimized Coatings: Halos and Reflections Suppressed\u003c\/h3\u003e\n      \u003cp\u003eModern CMOS sensors are notoriously reflective, often creating halos and internal reflections when paired with traditional filters. Every filter in this f\/2 set features Baader's Reflex-Blocker™ hard coatings and plane-optically polished surfaces. These treatments drastically reduce reflections, eliminating the halos around bright stars that can ruin an otherwise perfect image. Additionally, Baader's Life-Coat™ technology provides a hardened, scratch-resistant surface that withstands harsh cleaning and environmental conditions for years of use.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003e3.5nm \u0026amp; 4nm Bandpasses: Extreme Contrast for Emission Nebulae\u003c\/h3\u003e\n      \u003cp\u003eWith a full width at half maximum (FWHM) of just 3.5nm for H-alpha and S-II, and 4nm for O-III, these filters provide an extreme signal-to-noise ratio. This ultra-narrow bandpass rejects moonlight, city light pollution, and natural skyglow more effectively than wider 6.5nm or 7nm filters. The result is a darker background and significantly higher contrast, allowing faint structures within objects like the Pelican Nebula (IC 5070) or the Heart Nebula (IC 1805) to be recorded with greater clarity.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eBaader f\/2 Ultra-Highspeed vs. Standard f\/4+ Narrowband Filters\u003c\/h3\u003e\n      \u003cp\u003eWhile standard narrowband filters offer excellent results on slower systems, their performance degrades sharply at f\/2. This set is purpose-built for that specific application.\u003c\/p\u003e\n      \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eStandard 7nm Narrowband Filters:\u003c\/strong\u003e These are more forgiving on a wider range of focal ratios from f\/4 to f\/10. However, placed in an f\/2 system, their passband shifts so far that they may only transmit 50% or less of the target emission line's light.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eBaader f\/2 Ultra-Highspeed Filters:\u003c\/strong\u003e These are optimized for peak transmission from f\/1.8 to f\/3.5. On a slower f\/8 system, their pre-shifted bandpass would be off-target in the other direction, reducing their effectiveness. They are a specialist tool for a specialist optical system.\u003c\/li\u003e\n      \u003c\/ul\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Baader f\/2 Ultra-Highspeed filters on my f\/8 SCT?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eIt is not recommended. These Baader f\/2 filters are \"pre-shifted,\" meaning their center wavelength is intentionally offset to land perfectly on the emission line in a very fast f\/2 light cone. On an f\/8 system, this pre-shift would place the transmission band off-target, resulting in significant signal loss. For f\/4 or slower systems, Baader's standard 6.5nm or 7nm narrowband filters are the correct choice.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does \"CMOS-optimized\" mean for the Baader 3.5\/4nm filter set?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003e\u003cstrong\u003eCMOS-optimized\u003c\/strong\u003e refers to several design features that combat issues common with modern CMOS sensors. These include \u003cstrong\u003eReflex-Blocker™ coatings\u003c\/strong\u003e to prevent halos from reflections between the sensor and filter, plane-optically polished surfaces for sharpness, and sealed coating edges to prevent moisture intrusion. This ensures clean, artifact-free images even with bright stars in the field of view.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the 3.5nm bandpass on the Baader f\/2 filters affect imaging the Veil Nebula (NGC 6960) from my city backyard?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe ultra-narrow \u003cstrong\u003e3.5nm bandpass\u003c\/strong\u003e is extremely effective at isolating the specific light from the Veil Nebula while rejecting broad-spectrum light pollution from city skies. This drastically increases contrast, making the faint, filamentary structure of the nebula stand out against a dark background. Even with an f\/2 system's fast light-gathering ability, this level of filtering is critical for pulling out detail from light-polluted locations.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhy are the H-alpha and S-II filters 3.5nm while the Baader O-III filter is 4nm?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThis is a deliberate engineering choice. The O-III emission line is generally fainter in most nebulae compared to H-alpha. The slightly wider \u003cstrong\u003e4nm bandpass\u003c\/strong\u003e for O-III allows for slightly more signal to be gathered, improving the signal-to-noise ratio for this critical wavelength without compromising too much on contrast. The H-alpha and S-II lines can be filtered more aggressively at \u003cstrong\u003e3.5nm\u003c\/strong\u003e for maximum background rejection.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eAre these Baader 3.5\/4nm filters parfocal?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, all Baader filters within a given size and series are designed to be parfocal. This means you should not need to make significant, if any, focus adjustments when switching between the H-alpha, O-III, and S-II filters in this set, saving valuable imaging time.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Baader f\/2 Ultra-Highspeed filter set work with my Celestron RASA 8 at f\/2?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eAbsolutely. This filter set is designed precisely for instruments like the RASA 8. The f\/2 optimization ensures you get maximum signal transmission by counteracting the band-shift inherent to the RASA's f\/2 optical design, making this set a perfect match for unlocking the full potential of your astrograph.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Set\u003c\/td\u003e\n\u003ctd\u003eH-alpha, O-III, S-II\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-alpha Bandpass\u003c\/td\u003e\n\u003ctd\u003e3.5nm FWHM\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eO-III Bandpass\u003c\/td\u003e\n\u003ctd\u003e4nm FWHM\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eS-II Bandpass\u003c\/td\u003e\n\u003ctd\u003e3.5nm FWHM\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Optimization\u003c\/td\u003e\n\u003ctd\u003ef\/1.8 to f\/3.5 optical systems\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoatings\u003c\/td\u003e\n\u003ctd\u003eReflex-Blocker™ and Life-Coat™ Hard Coatings\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003ePlane-optically polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, 31mm Unmounted, 36mm Unmounted, 50.4mm Unmounted, 50x50mm Unmounted, 65x65mm Unmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.02 (1.25\" Round Mounted)\u003cbr\u003e0.04 (2\" Round Mounted, 50.4mm Round Unmounted Filter)\u003cbr\u003e0.01 (31mm Round Unmounted Filter, 36mm Round Unmounted Filter)\u003cbr\u003e0.06 (50x50mm Square Filter)\u003cbr\u003e0.10 (65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter shape\u003c\/td\u003e\n\u003ctd\u003eround (1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted Filter, 36mm Round Unmounted Filter, 50.4mm Round Unmounted Filter)\u003cbr\u003esquare (50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter mounted\u003c\/td\u003e\n\u003ctd\u003eMounted (LPFC 6mm) (1.25\" Round Mounted, 2\" Round Mounted)\u003cbr\u003eUnmounted (31mm Round Unmounted Filter, 36mm Round Unmounted Filter, 50.4mm Round Unmounted Filter, 50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eCMOS, CCD, H-alpha, O-III, S-II\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType of Filter\u003c\/td\u003e\n\u003ctd\u003ef\/2 Ultra-Highspeed\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpecial Features\u003c\/td\u003e\n\u003ctd\u003eCMOS-optimized with Life-Coat™\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thickness (without cell)\u003c\/td\u003e\n\u003ctd\u003e2 mm (1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted Filter, 36mm Round Unmounted Filter)\u003cbr\u003e3 mm (50.4mm Round Unmounted Filter, 50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCWL (Central Wavelength)\u003c\/td\u003e\n\u003ctd\u003e656.3 nm \/ 500.7 nm \/ 671.7 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003eReflex-Blocker™ hard coated, planeoptically polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSuitable for f\/ratio\u003c\/td\u003e\n\u003ctd\u003e\u0026lt; f\/2.3\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cul class=\"DAV-grid\"\u003e\n    \u003cli class=\"DAV-grid-item\"\u003e\n      \u003cdiv\u003e\n        \u003cp class=\"DAV-item-title\"\u003eH-alpha 3.5nm f\/2 Ultra-Highspeed Filter\u003c\/p\u003e\n        \u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/li\u003e\n    \u003cli class=\"DAV-grid-item\"\u003e\n      \u003cdiv\u003e\n        \u003cp class=\"DAV-item-title\"\u003eO-III 4nm f\/2 Ultra-Highspeed Filter\u003c\/p\u003e\n        \u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/li\u003e\n    \u003cli class=\"DAV-grid-item\"\u003e\n      \u003cdiv\u003e\n        \u003cp class=\"DAV-item-title\"\u003eS-II 3.5nm f\/2 Ultra-Highspeed Filter\u003c\/p\u003e\n        \u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/li\u003e\n    \u003cli class=\"DAV-grid-item\"\u003e\n      \u003cdiv\u003e\n        \u003cp class=\"DAV-item-title\"\u003eIndividual Filter Cases\u003c\/p\u003e\n        \u003cp class=\"DAV-item-subtitle\"\u003e× 3\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_Filter_Problems_FAQ_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium Filter Problems FAQ Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_Narrowband_Filters_on_Astronomical_Telescopes_Whitepaper.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium Narrowband Filters on Astronomical Telescopes Whitepaper\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/baader-planetarium-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eBaader Planetarium Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"1.25\" Round Mounted","offer_id":44967910670621,"sku":"BAA-2961680","price":1151.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967910703389,"sku":"BAA-2961683","price":1723.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted Filter","offer_id":44967910736157,"sku":"BAA-2961681","price":1222.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted Filter","offer_id":44967910768925,"sku":"BAA-2961682","price":1464.0,"currency_code":"CAD","in_stock":true},{"title":"50.4mm Round Unmounted Filter","offer_id":44967910801693,"sku":"BAA-2961684","price":1863.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Filter","offer_id":44967910834461,"sku":"BAA-2961685","price":1986.0,"currency_code":"CAD","in_stock":true},{"title":"65x65mm Square Filter","offer_id":44967910867229,"sku":"BAA-2961686","price":2607.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader-f-2-Highspeed-Filter-Set-H-alpha-O-III-S-II-1__52568.1597110925.1280.1280__21214.1623461173.1280.1280.jpg?v=1684346897"},{"product_id":"baader-6-5nm-oiii-filter-cmos-optimized","title":"Baader 6.5nm OIII Filter - CMOS-Optimized","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e6.5nm FWHM Bandpass\u003c\/li\u003e\n\u003cli\u003eOptimized for Modern CMOS Sensors\u003c\/li\u003e\n\u003cli\u003eReflex-Blocker™ Hard Coatings\u003c\/li\u003e\n\u003cli\u003eAvailable in 7 Formats (Mounted and Unmounted)\u003c\/li\u003e\n\u003cli\u003ePlane-Parallel Substrate\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eBaader 6.5nm OIII Filter - CMOS-Optimized\u003c\/h2\u003e\n\u003cp\u003eThe Baader 6.5nm OIII Filter isolates the critical doubly-ionized oxygen emission lines with a tight 6.5nm full-width at half-maximum (FWHM) bandpass. Available in 7 distinct formats from 1.25\" round mounted to 65x65mm square, this filter is specifically engineered with Reflex-Blocker™ coatings to suppress the reflections and halos common with modern, highly-reflective CMOS sensors.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe 6.5nm OIII Bandpass for High-Contrast Imaging\u003c\/h3\u003e\n\u003cp\u003eBy restricting the incoming light to a narrow 6.5nm window centered on the 500.7nm OIII line, this filter dramatically increases the contrast of emission nebulae against the skyglow background. This tight bandpass effectively eliminates light pollution, moonlight, and natural airglow, allowing faint, intricate structures within planetary nebulae and supernova remnants to become clearly visible in your images.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eReflex-Blocker Coatings for Modern Sensors\u003c\/h3\u003e\n\u003cp\u003eModern CMOS sensors are significantly more reflective than their CCD predecessors, which can introduce halos and internal reflections around bright stars, especially in fast optical systems. Baader's CMOS-optimized design incorporates advanced Reflex-Blocker™ hard coatings, which are specifically formulated to minimize these reflections. The result is cleaner data with higher contrast, deeper blacks, and halo-free stars, allowing for more aggressive processing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e7 Formats for Every Optical System\u003c\/h3\u003e\n\u003cp\u003eTo accommodate nearly any imaging setup, the Baader 6.5nm OIII filter is available in 7 different sizes. This ensures proper fitting and illumination for everything from small ZWO cameras to large-format systems with extensive filter carousels.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMounted (1.25\" \u0026amp; 2\"):\u003c\/strong\u003e Standard threaded cells for universal compatibility with most filter wheels and eyepiece holders.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUnmounted Round (31mm, 36mm, 50.4mm):\u003c\/strong\u003e For dedicated filter wheels that require unmounted filters to maximize clear aperture and minimize weight.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUnmounted Square (50x50mm \u0026amp; 65x65mm):\u003c\/strong\u003e Designed for professional-grade cameras and large filter drawers where maximum sensor coverage is required.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does \"CMOS-Optimized\" mean for the Baader 6.5nm OIII filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\"CMOS-Optimized\" means the filter's anti-reflection coatings are specifically designed to handle the high reflectivity of modern CMOS sensors. This prevents halos, reflections, and other artifacts that can appear around bright stars when using filters designed for older, less-reflective CCD cameras, particularly with fast telescopes (f\/5 or lower).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the 6.5nm bandpass on this Baader OIII filter improve images from a light-polluted location?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe narrow \u003cstrong\u003e6.5nm bandpass\u003c\/strong\u003e acts as a gate, allowing light from emission nebulae (specifically, the OIII line at 500.7nm) to pass through while blocking nearly everything else. This includes common sources of light pollution like sodium and mercury vapor streetlights, as well as natural skyglow. This dramatically darkens the sky background in your images, significantly increasing the contrast and visibility of your target.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Baader 6.5nm OIII filter suitable for visual use?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eGenerally, a 6.5nm bandpass is too restrictive for satisfying visual observation, as it dims the image considerably. While it can be effective on extremely bright objects like the Orion Nebula (M42) with large-aperture telescopes (10\" or more), it is primarily designed for long-exposure astrophotography where a camera can accumulate the faint signal over time.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhich size of the Baader 6.5nm OIII filter do I need for my setup?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe correct size depends on your camera and filter wheel. Here's a general guide:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25\" Mounted:\u003c\/strong\u003e Best for cameras with sensors smaller than the APS-C format (e.g., ZWO ASI533, ASI183).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2\" Mounted:\u003c\/strong\u003e Ideal for full-frame sensors or to avoid vignetting with very fast (f\/2-f\/4) optical systems, even with smaller sensors.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e31mm \u0026amp; 36mm Unmounted:\u003c\/strong\u003e Common sizes for specific filter wheels from brands like ZWO and QHY. Check your filter wheel's manual for the required size.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e50.4mm, 50x50mm, 65x65mm:\u003c\/strong\u003e For large-format sensors found in high-end astronomical cameras.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Baader 6.5nm OIII filter perform on the Veil Nebula (NGC 6960) with an 8\" f\/4 Newtonian?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis filter is an excellent choice for the Veil Nebula (NGC 6960), which is a strong OIII emitter. With an 8\" f\/4 system, the tight 6.5nm bandpass will provide exceptional contrast, revealing the fine, filamentary details of the supernova remnant while keeping star sizes tight and free of halos, thanks to the CMOS-optimized coatings.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Baader 6.5nm OIII filter to image planetary nebulae like the Ring Nebula (M57) from my city backyard?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. The Ring Nebula (M57) is a classic OIII target, and this filter is perfectly suited for imaging it from urban or suburban locations. The 6.5nm bandpass will effectively cut through light pollution, allowing you to capture the nebula's delicate structure and central star, which would otherwise be washed out by skyglow.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandpass\u003c\/td\u003e\n\u003ctd\u003e6.5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTarget Wavelength\u003c\/td\u003e\n\u003ctd\u003eOIII (500.7nm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptimization\u003c\/td\u003e\n\u003ctd\u003eCMOS Sensors\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Formats\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, 31mm Unmounted, 36mm Unmounted, 50.4mm Unmounted, 50x50mm Square, 65x65mm Square\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.01 (1.25\" Round Mounted, 2\" Round Mounted, 50.4mm Round Unmounted Filter)\u003cbr\u003e0.02 (50x50mm Square Filter)\u003cbr\u003e0.03 (65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter shape\u003c\/td\u003e\n\u003ctd\u003eround (1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted Filter, 36mm Round Unmounted Filter, 50.4mm Round Unmounted Filter)\u003cbr\u003esquare (50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSingle or Set?\u003c\/td\u003e\n\u003ctd\u003eSingle Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter mounted\u003c\/td\u003e\n\u003ctd\u003eMounted (LPFC 6mm) (1.25\" Round Mounted, 2\" Round Mounted)\u003cbr\u003eUnmounted (31mm Round Unmounted Filter, 36mm Round Unmounted Filter, 50.4mm Round Unmounted Filter, 50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eCMOS, CCD, O-III\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType of Filter\u003c\/td\u003e\n\u003ctd\u003eNarrowband\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpecial Features\u003c\/td\u003e\n\u003ctd\u003eCMOS-optimized with Life-Coat™\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thickness (without cell)\u003c\/td\u003e\n\u003ctd\u003e2 mm (1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted Filter, 36mm Round Unmounted Filter)\u003cbr\u003e3 mm (50.4mm Round Unmounted Filter, 50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003eReflex-Blocker™ hard coated, planeoptically polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSuitable for f\/ratio\u003c\/td\u003e\n\u003ctd\u003e\u0026gt; f\/3.4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader 6.5nm OIII CMOS-Optimized Filter (Selected Size)\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_Cleaning_and_Maintenance_of_Optics_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium Cleaning and Maintenance of Optics Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_Narrowband_Filters_on_Astronomical_Telescopes_Whitepaper.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium Narrowband Filters on Astronomical Telescopes Whitepaper\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_We_Found_the_Way_Presentation_by_Christoph_Kaltseis.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium We Found the Way Presentation by Christoph Kaltseis\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/baader-planetarium-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eBaader Planetarium Warranty Policy\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"1.25\" Round Mounted","offer_id":44967918338333,"sku":"BAA-2961175","price":213.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967918371101,"sku":"BAA-2961178","price":360.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted Filter","offer_id":44967918403869,"sku":"BAA-2961176","price":225.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted Filter","offer_id":44967918436637,"sku":"BAA-2961177","price":257.0,"currency_code":"CAD","in_stock":true},{"title":"50.4mm Round Unmounted Filter","offer_id":44967918469405,"sku":"BAA-2961179","price":431.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Filter","offer_id":44967918502173,"sku":"BAA-2961180","price":446.0,"currency_code":"CAD","in_stock":true},{"title":"65x65mm Square Filter","offer_id":44967918534941,"sku":"BAA-2961181","price":557.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/baader-oiii-6-5nm-narrowband-filters-cmos-optimized__20434.1632877804.1280.1280.jpg?v=1684347027"},{"product_id":"baader-6-5nm-sii-filter-cmos-optimized","title":"Baader 6.5nm SII Filter - CMOS-Optimized","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e6.5nm FWHM Bandpass\u003c\/li\u003e\n\u003cli\u003eOptimized for Modern CMOS Sensors\u003c\/li\u003e\n\u003cli\u003eSuppresses Halos and Internal Reflections\u003c\/li\u003e\n\u003cli\u003eHigh-Contrast for Sulfur-II Emission Nebulae\u003c\/li\u003e\n\u003cli\u003eAvailable in Multiple Mounted and Unmounted Sizes\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eBaader 6.5nm SII Filter - CMOS-Optimized\u003c\/h2\u003e\n\u003cp\u003eThe Baader CMOS-Optimized SII Filter uses a tight 6.5nm bandpass to isolate the faint, deep-red light of ionized sulfur, a key structural component in bicolor and Hubble-palette astrophotography. This narrow window is specifically engineered to reject light pollution and moonlight, ensuring maximum signal-to-noise on emission nebulae when using modern, high-sensitivity CMOS sensors.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eHigh-Contrast SII Imaging with a 6.5nm Bandpass\u003c\/h3\u003e\n\u003cp\u003eBy restricting transmission to a narrow 6.5nm window centered on the Sulfur-II emission line, this filter renders the faint, intricate structures within nebulae like the Eagle Nebula (M16) and the Rosette Nebula (NGC 2237) with stark contrast. The tight bandpass darkens the sky background by rejecting unwanted artificial and natural light, allowing your sensor to record pure signal for cleaner, more detailed final images.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eCMOS-Optimized for Modern Sensors\u003c\/h3\u003e\n\u003cp\u003eLegacy narrowband filters were not designed to handle the highly reflective nature of modern CMOS sensor packages. When paired with these sensors, older filters often produce distracting halos and internal reflections around bright stars. Baader's CMOS-optimized design incorporates advanced coating systems engineered to eliminate these artifacts at the source, saving you hours of complex post-processing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eAdvanced Coatings for Halo Suppression and Durability\u003c\/h3\u003e\n\u003cp\u003eEach filter is planeoptically polished to ensure a sharp, distortion-free image and features advanced anti-reflection coatings. These coatings are not only essential for preventing halos but are also exceptionally hard and durable. This protects the filter from the effects of cleaning and exposure to the elements, ensuring consistent results for years of use.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eAvailable in 7 Sizes for Any Optical Train\u003c\/h3\u003e\n\u003cp\u003eTo accommodate nearly any imaging setup, the Baader 6.5nm SII filter is available in seven standard sizes. Whether you need a 1.25\" or 2\" mounted filter for a standard filter wheel, or an unmounted 31mm, 36mm, 50.4mm, 50x50mm, or 65x65mm filter for a dedicated camera or filter drawer, there is an option to fit your optical train perfectly.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat makes the Baader 6.5nm SII filter \"CMOS-Optimized\"?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \"CMOS-Optimized\" designation means the filter's anti-reflection coatings are specifically designed to suppress the halos and internal reflections that occur when using modern, highly reflective CMOS sensors. Legacy filters designed for older CCD technology often struggle with this, producing artifacts around bright stars that these Baader filters prevent.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does a 6.5nm bandpass on the Baader SII filter improve my images of the Eagle Nebula (M16)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Eagle Nebula (M16) has strong Sulfur-II emissions that define the structure of its famous \"Pillars of Creation.\" A tight \u003cstrong\u003e6.5nm bandpass\u003c\/strong\u003e isolates this specific light, rejecting light pollution and even strong moonlight. This dramatically increases the contrast of the pillars against the background sky, revealing finer details and structure that would be lost with a broader filter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Baader CMOS-Optimized SII filter with my fast f\/4 Newtonian telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. A key part of the Baader CMOS-optimized design is ensuring the filter performs well with fast optical systems. The coatings and glass substrate are designed to minimize the bandpass shift that can occur with the steep light cones from fast telescopes, ensuring consistent performance even at focal ratios like f\/4.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy should I choose the Baader 6.5nm SII filter over an older CCD-era filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIf you use a CMOS camera, the Baader 6.5nm SII filter is the superior choice. Older CCD filters lack the advanced anti-reflection coatings needed to prevent halos with reflective CMOS sensors. While a CCD filter may be less expensive, the Baader CMOS-Optimized filter will produce cleaner raw data, requiring significantly less effort in post-processing to remove artifacts.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the benefit of imaging with a Baader SII filter for the Hubble Palette (SHO)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIn the Hubble Palette, Sulfur-II (SII) data is typically mapped to the red channel. The Baader \u003cstrong\u003e6.5nm SII filter\u003c\/strong\u003e captures the unique structural details present in this emission line, which often differ from Hydrogen-alpha. This adds a critical layer of color differentiation and structural complexity to your final SHO composite image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I choose the right size Baader 6.5nm SII filter for my setup?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe correct size depends on your camera sensor and filter holder.\n\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25\" and 31mm:\u003c\/strong\u003e Best for smaller sensors (e.g., ASI1600, ASI294) to prevent vignetting.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2\" and 36mm:\u003c\/strong\u003e Ideal for APS-C sized sensors.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e50.4mm, 50x50mm, and 65x65mm:\u003c\/strong\u003e Required for full-frame and larger sensors to ensure the entire sensor is illuminated without vignetting.\u003c\/li\u003e\n\u003c\/ul\u003e\nAlways check your filter wheel or drawer specifications to confirm compatibility.\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandpass (FWHM)\u003c\/td\u003e\n\u003ctd\u003e6.5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEmission Line\u003c\/td\u003e\n\u003ctd\u003eSulfur-II (SII)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSensor Optimization\u003c\/td\u003e\n\u003ctd\u003eCMOS\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" (Mounted), 2\" (Mounted), 31mm (Unmounted), 36mm (Unmounted), 50.4mm (Unmounted), 50x50mm (Square), 65x65mm (Square)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.01 (1.25\" Round Mounted, 2\" Round Mounted, 50.4mm Round Unmounted Filter)\u003cbr\u003e0.02 (50x50mm Square Filter)\u003cbr\u003e0.03 (65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter shape\u003c\/td\u003e\n\u003ctd\u003eround (1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted Filter, 36mm Round Unmounted Filter, 50.4mm Round Unmounted Filter)\u003cbr\u003esquare (50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSingle or Set?\u003c\/td\u003e\n\u003ctd\u003eSingle Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter mounted\u003c\/td\u003e\n\u003ctd\u003eMounted (LPFC 6mm) (1.25\" Round Mounted, 2\" Round Mounted)\u003cbr\u003eUnmounted (31mm Round Unmounted Filter, 36mm Round Unmounted Filter, 50.4mm Round Unmounted Filter, 50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eCMOS, CCD, S-II\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType of Filter\u003c\/td\u003e\n\u003ctd\u003eNarrowband\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpecial Features\u003c\/td\u003e\n\u003ctd\u003eCMOS-optimized with Life-Coat™\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thickness (without cell)\u003c\/td\u003e\n\u003ctd\u003e2 mm (1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted Filter, 36mm Round Unmounted Filter)\u003cbr\u003e3 mm (50.4mm Round Unmounted Filter, 50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCWL (Central Wavelength)\u003c\/td\u003e\n\u003ctd\u003e671.7 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003eReflex-Blocker™ hard coated, planeoptically polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSuitable for f\/ratio\u003c\/td\u003e\n\u003ctd\u003e\u0026gt; f\/3.4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader 6.5nm SII CMOS-Optimized Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e(Size as selected)\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eFilter Case\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e(For individual filters)\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_Narrowband_Filters_on_Astronomical_Telescopes_Whitepaper.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium Narrowband Filters on Astronomical Telescopes Whitepaper\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_We_Found_the_Way_Presentation_by_Christoph_Kaltseis.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium We Found the Way Presentation by Christoph Kaltseis\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/baader-planetarium-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eBaader Planetarium Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"1.25\" Round Mounted","offer_id":44967918698781,"sku":"BAA-2961250","price":210.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967918731549,"sku":"BAA-2961253","price":357.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted Filter","offer_id":44967918764317,"sku":"BAA-2961251","price":223.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted Filter","offer_id":44967918797085,"sku":"BAA-2961252","price":255.0,"currency_code":"CAD","in_stock":true},{"title":"50.4mm Round Unmounted Filter","offer_id":44967918829853,"sku":"BAA-2961254","price":427.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Filter","offer_id":44967918862621,"sku":"BAA-2961255","price":445.0,"currency_code":"CAD","in_stock":true},{"title":"65x65mm Square Filter","offer_id":44967918895389,"sku":"BAA-2961256","price":552.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/baader-sii-narrowband-6-5nm-filters-cmos-optimized__75207.1632878092.1280.1280.jpg?v=1684347029"},{"product_id":"baader-4nm-ultra-narrowband-oiii-filter-cmos-optimized","title":"Baader 4nm Ultra-Narrowband OIII Filter - CMOS-Optimized","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e4nm Ultra-Narrowband OIII Bandpass\u003c\/li\u003e\n\u003cli\u003eOptimized for Modern CMOS Sensors\u003c\/li\u003e\n\u003cli\u003eReflex-Blocker™ Hard Coatings to Prevent Halos\u003c\/li\u003e\n\u003cli\u003eLife-Coat™ Technology for Extreme Durability\u003c\/li\u003e\n\u003cli\u003eAvailable in Multiple Mounted and Unmounted Sizes\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eBaader 4nm Ultra-Narrowband OIII Filter - CMOS-Optimized\u003c\/h2\u003e\n\u003cp\u003eThe Baader 4nm Ultra-Narrowband OIII Filter isolates the critical doubly-ionized oxygen emission line with a surgically precise 4nm bandpass, delivering maximum contrast for imaging emission nebulae. By aggressively blocking light pollution, moonlight, and extraneous starlight, this filter reveals the faintest filamentary details in targets like the Veil Nebula (NGC 6960) that are lost with wider filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe 4nm OIII Bandpass Advantage for Maximum Contrast\u003c\/h3\u003e\n\u003cp\u003eAn ultra-narrow 4nm bandpass is an aggressive tool for astrophotography. It transmits only the light from ionized oxygen, dramatically darkening the sky background and increasing the signal-to-noise ratio on emission targets. This extreme selectivity makes the Baader 4nm OIII filter exceptionally effective even under moonlit or heavily light-polluted skies, turning compromised nights into productive imaging sessions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eReflex-Blocker Coatings for Halo-Free CMOS Imaging\u003c\/h3\u003e\n\u003cp\u003eModern CMOS sensors are notoriously reflective, often causing halos and internal reflections with traditional filters. Baader's CMOS-optimized filters directly address this with advanced Reflex-Blocker™ hard coatings. These coatings are meticulously designed to suppress reflections between the filter and the sensor, ensuring that bright stars like those in the Trapezium of the Orion Nebula (M42) remain sharp points of light, free from distracting artifacts.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eLife-Coat Durability and Plano-Parallel Optical Substrate\u003c\/h3\u003e\n\u003cp\u003eEach Baader filter is built on a fine-optically polished, plano-parallel substrate, ensuring it will not degrade the resolution of your optical system. The dielectric coatings are applied with an Ion-Beam Assisted Deposition process, creating an incredibly hard, scratch-resistant surface. This Life-Coat™ technology means the filter can be cleaned repeatedly without fear of damage, guaranteeing its optical properties for a lifetime of use.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eBaader 4nm vs. 7nm OIII: When to Choose Ultra-Narrowband\u003c\/h3\u003e\n\u003cp\u003eChoosing between a 4nm and a wider 7nm filter involves a direct trade-off between contrast and exposure time.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eWider (7nm) OIII Filter:\u003c\/strong\u003e Gathers light more quickly, allowing for shorter sub-exposures. It can be more forgiving of minor tracking errors and is often sufficient for dark-sky locations where light pollution is not the primary challenge.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBaader 4nm OIII Filter:\u003c\/strong\u003e Provides significantly higher contrast, which is essential for pulling faint details out from a bright sky background. While it requires longer exposure times, the resulting data is cleaner and reveals more intricate nebular structures, making it the superior choice for suburban imagers or anyone pursuing the highest possible detail.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat makes the Baader 4nm OIII filter \"CMOS-Optimized\"?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \"CMOS-Optimized\" design refers to Baader's proprietary \u003cstrong\u003eReflex-Blocker™ hard coatings\u003c\/strong\u003e. These coatings are specifically engineered to prevent halos and internal reflections that can occur between a modern, highly-reflective CMOS sensor and the filter surface. This results in cleaner images with sharper stars and fewer artifacts.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Baader 4nm OIII filter perform on the Veil Nebula (NGC 6960) with an f\/5 Newtonian?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Baader 4nm OIII filter is ideal for targets like the Veil Nebula. Its extreme 4nm bandpass will produce outstanding contrast, separating the delicate, rope-like filaments of the nebula from the background sky. With an f\/5 system, you will be able to capture deep data, but be prepared for longer sub-exposures compared to a wider filter to achieve a strong signal.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Baader 4nm OIII filter good for imaging planetary nebulae like the Ring Nebula (M57)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, it is an excellent choice. Planetary nebulae are rich in OIII emissions. The 4nm bandpass will isolate the nebula's light, darken the sky background significantly, and help reveal faint structural details within the Ring Nebula (M57), such as its central star and subtle variations in the ring itself.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill I need longer exposures with the Baader 4nm OIII filter compared to a 7nm version?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. By restricting the bandpass to 4nm, the filter passes less light overall, including starlight. You should expect to roughly double your exposure time compared to a 7nm filter to achieve the same signal level. The benefit of this is a dramatic increase in contrast and rejection of unwanted light pollution.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the Baader 4nm OIII filter cause halos around bright stars?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this filter is specifically designed to prevent halos. The combination of the Reflex-Blocker™ coatings, non-aging sealed coating edges, and a high-quality plano-parallel substrate ensures that reflections are minimized, even on the brightest stars in the field of view.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs this Baader 4nm filter parfocal with other Baader CMOS-optimized filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. Baader manufactures their CMOS-optimized narrowband, LRGB, and high-speed filters to be parfocal. This means you can switch between filters in your filter wheel without needing to refocus, which is a critical time-saver for automated imaging sequences.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandpass\u003c\/td\u003e\n\u003ctd\u003e4nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTarget Emission Line\u003c\/td\u003e\n\u003ctd\u003eOIII (Doubly Ionized Oxygen)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCMOS Optimized\u003c\/td\u003e\n\u003ctd\u003eYes, with Reflex-Blocker™ Coatings\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted, 36mm Round Unmounted, 50.4mm Round Unmounted, 50x50mm Square, 65x65mm Square\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.01 (1.25\" Round Mounted, 2\" Round Mounted, 50.4mm Round Unmounted Filter)\u003cbr\u003e0.02 (50x50mm Square Filter)\u003cbr\u003e0.03 (65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter shape\u003c\/td\u003e\n\u003ctd\u003eround (1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted Filter, 36mm Round Unmounted Filter, 50.4mm Round Unmounted Filter)\u003cbr\u003esquare (50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSingle or Set?\u003c\/td\u003e\n\u003ctd\u003eSingle Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter mounted\u003c\/td\u003e\n\u003ctd\u003eMounted (LPFC 6mm) (1.25\" Round Mounted, 2\" Round Mounted)\u003cbr\u003eUnmounted (31mm Round Unmounted Filter, 36mm Round Unmounted Filter, 50.4mm Round Unmounted Filter, 50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eCMOS, CCD, O-III\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType of Filter\u003c\/td\u003e\n\u003ctd\u003eUltra-Narrowband\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpecial Features\u003c\/td\u003e\n\u003ctd\u003eCMOS-optimized with Life-Coat™\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thickness (without cell)\u003c\/td\u003e\n\u003ctd\u003e2 mm (1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted Filter, 36mm Round Unmounted Filter)\u003cbr\u003e3 mm (50.4mm Round Unmounted Filter, 50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCWL (Central Wavelength)\u003c\/td\u003e\n\u003ctd\u003e500.7 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003eReflex-Blocker™ hard coated, planeoptically polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSuitable for f\/ratio\u003c\/td\u003e\n\u003ctd\u003e\u0026gt; f\/3.4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_Narrowband_Filters_on_Astronomical_Telescopes_Whitepaper.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium Narrowband Filters on Astronomical Telescopes Whitepaper\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_We_Found_the_Way_Presentation_by_Christoph_Kaltseis.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium We Found the Way Presentation by Christoph Kaltseis\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/baader-planetarium-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eBaader Planetarium Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"1.25\" Round Mounted","offer_id":44967919517981,"sku":"BAA-2961400","price":382.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967919550749,"sku":"BAA-2961403","price":560.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted Filter","offer_id":44967919583517,"sku":"BAA-2961401","price":413.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted Filter","offer_id":44967919616285,"sku":"BAA-2961402","price":494.0,"currency_code":"CAD","in_stock":true},{"title":"50.4mm Round Unmounted Filter","offer_id":44967919649053,"sku":"BAA-2961404","price":603.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Filter","offer_id":44967919681821,"sku":"BAA-2961405","price":618.0,"currency_code":"CAD","in_stock":true},{"title":"65x65mm Square Filter","offer_id":44967919714589,"sku":"BAA-2961406","price":822.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Baader-OIII-4nm-Ultra-Narrowband-Filters__49024.1634234378.1280.1280.jpg?v=1684347031"},{"product_id":"baader-6-5nm-h-alpha-filter-cmos-optimized","title":"Baader 6.5nm H-alpha Filter - CMOS-Optimized","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e6.5nm FWHM Bandpass\u003c\/li\u003e\n\u003cli\u003eCMOS-Optimized Anti-Reflection Coatings\u003c\/li\u003e\n\u003cli\u003eReflex-Blocker™ coatings to prevent halos\u003c\/li\u003e\n\u003cli\u003eLife-Coat™ scratch-resistant hard coatings\u003c\/li\u003e\n\u003cli\u003eAvailable in multiple mounted and unmounted sizes\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eBaader 6.5nm H-alpha CMOS-Optimized Filter\u003c\/h2\u003e\n\u003cp\u003eThe Baader 6.5nm H-alpha Filter isolates the critical hydrogen-alpha emission line with a tight 6.5nm full-width half-maximum (FWHM) bandpass, engineered specifically to deliver maximum contrast with modern CMOS sensors. By aggressively blocking extraneous wavelengths from light pollution and moonlight, this 6.5nm filter reveals faint, extended structures in emission nebulae that are invisible to wider filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eA 6.5nm Bandpass for Maximum Nebula Contrast\u003c\/h3\u003e\n\u003cp\u003eThe 6.5nm bandpass is a significant step up from wider 7nm or 12nm filters, providing a darker sky background and making faint nebulosity stand out with greater definition. This narrower window tightens the signal-to-noise ratio, allowing you to capture intricate details within H-II regions like the California Nebula (NGC 1499) or the Rosette Nebula (NGC 2237), even from moderately light-polluted locations.\u003c\/p\u003e\n\u003cp\u003eWhile a narrower bandpass requires slightly longer sub-exposure times, the resulting increase in contrast is substantial. The trade-off is more signal and less background noise, which simplifies processing and produces a cleaner final image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eReflex-Blocker Coatings: CMOS Optimization to Eliminate Halos\u003c\/h3\u003e\n\u003cp\u003eModern CMOS sensors are highly reflective, a characteristic that causes halos and internal reflections with legacy filter designs. Baader's CMOS-optimized filters combat this with advanced Reflex-Blocker™ coatings, which are applied to both sides of the substrate to effectively eliminate reflections between the filter and the sensor cover glass.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eHalo Suppression:\u003c\/strong\u003e These multi-layer dielectric coatings are painstakingly optimized to prevent the reflections that cause bright stars to produce distracting rings and halos in your images.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaximized Transmission:\u003c\/strong\u003e By minimizing reflections, these coatings also ensure that the maximum amount of critical H-alpha light reaches the sensor, preserving signal from your target.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eLife-Coat Hardening: Durability for a Lifetime of Imaging\u003c\/h3\u003e\n\u003cp\u003eBaader applies its proprietary Life-Coat™ hard coating technology, creating an incredibly durable, scratch-resistant filter surface. This process makes the filter non-aging and capable of withstanding the harsh conditions of field use and repeated cleanings without degradation of its optical properties.\u003c\/p\u003e\n\u003cp\u003eThis investment in durability ensures your filter's transmission and bandpass characteristics will remain stable for years. The substrate is also fine-optically polished to maintain the sharpness of your optical system, ensuring that adding the filter does not degrade the resolution of your telescope.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eBaader 6.5nm H-alpha vs. Wider and Narrower Filters\u003c\/h3\u003e\n\u003cp\u003eChoosing the right bandpass is a critical decision for an astrophotographer. The Baader 6.5nm filter occupies a strategic position between wider, more forgiving filters and ultra-narrow, more demanding ones.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003evs. 7nm Filters:\u003c\/strong\u003e A 7nm filter is often a starting point for many imagers and performs well with fast optical systems (f\/5 or faster). The Baader 6.5nm offers a noticeable contrast improvement over a 7nm, darkening the sky background more effectively at a minimal cost to exposure time.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003evs. 3.5nm Filters:\u003c\/strong\u003e An ultra-narrow 3.5nm filter provides the ultimate in contrast, but at a cost. It requires significantly longer exposure times, is less forgiving of minor tracking errors, and can be more susceptible to band-shifting with very fast f-ratios. The 6.5nm filter is a more balanced choice, providing excellent contrast without the demanding requirements of an ultra-narrowband filter.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Baader 6.5nm H-alpha filter for solar observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eAbsolutely not.\u003c\/strong\u003e This is a deep-sky narrowband filter and is completely unsafe for any type of solar observation, visual or photographic, without a dedicated, full-aperture solar filter on the front of your telescope. The 6.5nm bandpass is thousands of times wider than a specialized solar H-alpha filter (which are typically under 0.1nm). Attempting to view the Sun with this filter will cause permanent and instant eye damage.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does \"CMOS-optimized\" mean for the Baader 6.5nm H-alpha filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt means the filter is specifically designed to prevent the halos and internal reflections that occur when using filters with modern, highly-reflective CMOS sensors. Baader uses advanced \u003cstrong\u003eReflex-Blocker™\u003c\/strong\u003e coatings that are applied to both sides of the filter to neutralize these reflections, ensuring clean, halo-free images even around the brightest stars.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Baader 6.5nm H-alpha filter improve my images of the Heart Nebula (IC 1805) from my backyard?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Heart Nebula is a classic H-alpha target. From a typical suburban backyard, a 6.5nm filter will dramatically darken the sky background caused by city lights. This increases the contrast between the faint hydrogen gas of the nebula and the sky, allowing you to capture far more detail and structure with shorter total integration times than you could with a wider filter or no filter at all.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Baader 6.5nm filter suitable for my f\/4 Newtonian telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this filter performs well with faster optical systems. While extremely fast scopes (f\/3 and below) can sometimes cause a slight \"band-shift\" with narrowband filters, the 6.5nm bandpass is wide enough to be very forgiving. It will provide a significant contrast boost on your f\/4 Newtonian without the issues that can affect ultra-narrow 3nm or 3.5nm filters on fast systems.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the 6.5nm bandpass affect my exposure times compared to a 7nm filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eMoving from a 7nm filter to a 6.5nm filter will require a modest increase in your sub-exposure length to achieve the same signal level on the nebula itself. However, because the 6.5nm filter blocks more background light, you will achieve a higher signal-to-noise ratio in the same total imaging time. The result is a cleaner image with better contrast for a minimal increase in sub-exposure duration.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eAre these Baader filters parfocal with each other?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, Baader's CMOS-optimized narrowband and LRGB filters are designed to be parfocal. This means you can switch between your H-alpha, OIII, SII, and LRGB filters during an imaging session without having to refocus your camera, saving valuable time and ensuring sharp data across all channels.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted, 36mm Round Unmounted, 50.4mm Round Unmounted, 50x50mm Square, 65x65mm Square\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.01 (1.25\" Round Mounted, 2\" Round Mounted, 50.4mm Round Unmounted Filter)\u003cbr\u003e0.02 (50x50mm Square Filter)\u003cbr\u003e0.03 (65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter shape\u003c\/td\u003e\n\u003ctd\u003eround (1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted Filter, 36mm Round Unmounted Filter, 50.4mm Round Unmounted Filter)\u003cbr\u003esquare (50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSingle or Set?\u003c\/td\u003e\n\u003ctd\u003eSingle Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter mounted\u003c\/td\u003e\n\u003ctd\u003eMounted (LPFC 6mm) (1.25\" Round Mounted, 2\" Round Mounted)\u003cbr\u003eUnmounted (31mm Round Unmounted Filter, 36mm Round Unmounted Filter, 50.4mm Round Unmounted Filter, 50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eCMOS, CCD, H-alpha\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType of Filter\u003c\/td\u003e\n\u003ctd\u003eNarrowband\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpecial Features\u003c\/td\u003e\n\u003ctd\u003eCMOS-optimized with Life-Coat™\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thickness (without cell)\u003c\/td\u003e\n\u003ctd\u003e2 mm (1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted Filter, 36mm Round Unmounted Filter)\u003cbr\u003e3 mm (50.4mm Round Unmounted Filter, 50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHBW (Halfbandwidth)\u003c\/td\u003e\n\u003ctd\u003e6.5 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCWL (Central Wavelength)\u003c\/td\u003e\n\u003ctd\u003e656.3 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission Range\u003c\/td\u003e\n\u003ctd\u003eH-alpha\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003eReflex-Blocker™ hard coated, planeoptically polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSuitable for f\/ratio\u003c\/td\u003e\n\u003ctd\u003e\u0026gt; f\/3.4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_Filter_Problems_FAQ_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium Filter Problems FAQ Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_Narrowband_Filters_on_Astronomical_Telescopes_Whitepaper.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium Narrowband Filters on Astronomical Telescopes Whitepaper\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_We_Found_the_Way_Presentation_by_Christoph_Kaltseis.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium We Found the Way Presentation by Christoph Kaltseis\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/baader-planetarium-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eBaader Planetarium Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"1.25\" Round Mounted","offer_id":44967920009501,"sku":"BAA-2961100","price":217.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967920042269,"sku":"BAA-2961103","price":369.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted Filter","offer_id":44967920075037,"sku":"BAA-2961101","price":228.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted Filter","offer_id":44967920107805,"sku":"BAA-2961102","price":258.0,"currency_code":"CAD","in_stock":true},{"title":"50.4mm Round Unmounted Filter","offer_id":44967920140573,"sku":"BAA-2961104","price":383.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Filter","offer_id":44967920173341,"sku":"BAA-2961105","price":439.0,"currency_code":"CAD","in_stock":true},{"title":"65x65mm Square Filter","offer_id":44967920206109,"sku":"BAA-2961106","price":564.0,"currency_code":"CAD","in_stock":true}]},{"product_id":"baader-3-5nm-4nm-narrowband-filter-set-cmos-optimized-h-alpha-o-iii-s-ii","title":"Baader 3.5nm \/ 4nm Narrowband Filter Set - CMOS-Optimized H-alpha\/O-III\/S-II","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e3-Filter Set: H-alpha (3.5nm), O-III (4nm), S-II (3.5nm)\u003c\/li\u003e\n\u003cli\u003eUltra-Narrow Bandpasses for Maximum Image Contrast\u003c\/li\u003e\n\u003cli\u003eCMOS-Optimized to Eliminate Halos and Internal Reflections\u003c\/li\u003e\n\u003cli\u003eParfocal Design Ensures Focus is Maintained Between Filters\u003c\/li\u003e\n\u003cli\u003eAvailable in 7 Formats, from 1.25\" Mounted to 65x65mm Square\u003c\/li\u003e\n\u003cli\u003eLife-Coat™ Hard Coatings for Enhanced Durability\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eBaader 3.5nm \/ 4nm Narrowband Filter Set - CMOS-Optimized H-alpha\/O-III\/S-II\u003c\/h2\u003e\n\u003cp\u003eThe Baader 3.5nm \/ 4nm Narrowband Filter Set provides imagers with three advanced filters—a 3.5nm H-alpha, a 4nm O-III, and a 3.5nm S-II—for capturing extreme-contrast Hubble Palette (SHO) images. Available in 7 formats from 1.25\" mounted to 65x65mm square, this set is specifically engineered with Reflex-Blocker™ coatings to suppress reflections and halos on modern CMOS sensors, even in fast optical systems.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e3.5nm \u0026amp; 4nm Bandpasses: CMOS-Optimized for Maximum Contrast\u003c\/h3\u003e\n\u003cp\u003eThis set pushes narrowband imaging to its practical limit with a 3.5nm bandpass for H-alpha and S-II, and a slightly wider 4nm for the dimmer O-III line. These ultra-narrow windows dramatically increase contrast by rejecting more unwanted light from urban skies, moonlight, and natural skyglow compared to wider 7nm or 12nm filters. The result is a darker background and enhanced definition in faint nebulosity.\u003c\/p\u003e\n\u003cp\u003eBaader's CMOS-optimized design is critical for modern cameras. These filters feature advanced dielectric coatings that are plane-parallel and hard-coated to prevent the internal reflections between the filter and sensor that cause halos around bright stars. This ensures clean, artifact-free data, especially with fast refractors or HyperStar systems.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eParfocal Design Across All 7 Filter Sizes\u003c\/h3\u003e\n\u003cp\u003eEngineered for efficiency, all filters in this Baader set are parfocal, eliminating the need to refocus when switching between H-alpha, O-III, and S-II. This saves critical imaging time and simplifies automated sequences with a filter wheel. This parfocal commitment holds true across all 7 available sizes, from standard 1.25\" and 2\" mounted filters to large-format unmounted options for flagship cameras.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eLife-Coat™ Durability:\u003c\/strong\u003e Baader's hard-coating technology provides a scratch-resistant surface that can withstand careful cleaning and harsh observing environments, ensuring a lifetime of use.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSealed Coating Edges:\u003c\/strong\u003e The coating material is sealed at the filter edge, preventing moisture intrusion and degradation over time, a common failure point in lesser filters.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConsistent Thickness:\u003c\/strong\u003e Each filter is polished to a high degree of plane-parallelism, preventing any image shift or distortion when placed in the optical path.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eA Critical Safety Warning for the 3.5nm H-alpha Filter\u003c\/h3\u003e\n\u003cp\u003eIt is imperative to understand that the 3.5nm H-alpha filter in this set is a deep-sky, nebular filter and is \u003cstrong\u003eabsolutely not safe for solar observation or imaging\u003c\/strong\u003e. Its 3.5nm (or 35 Ångström) bandpass is thousands of times wider than a dedicated solar H-alpha filter, which must have a bandpass under 1 Ångström to safely isolate the chromosphere.\u003c\/p\u003e\n\u003cp\u003eAttempting to view the Sun visually through this filter will cause immediate and permanent eye damage, including blindness. While photographic use on the Sun is theoretically possible with extreme caution and additional energy rejection filters, it is not the intended purpose of this product and is strongly discouraged.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does \"CMOS-Optimized\" mean for the Baader 3.5nm\/4nm filter set?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\"CMOS-Optimized\" means the filters are designed to combat internal reflections that occur between the highly-reflective surfaces of modern CMOS sensors and the filter itself. Baader uses advanced \u003cstrong\u003eReflex-Blocker™ coatings\u003c\/strong\u003e that are plane-parallel to prevent these reflections from creating halos and other artifacts around bright stars, a problem often seen with older filters not designed for modern sensors.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does this 3.5nm\/4nm Baader set compare to wider 7nm filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary advantage is \u003cstrong\u003ehigher contrast\u003c\/strong\u003e. By cutting the bandpass in half (from 7nm to 3.5nm), the filters reject significantly more light pollution, moonlight, and natural airglow. This results in a darker sky background and makes faint nebulosity stand out more clearly. The trade-off is that exposures need to be longer to achieve the same signal level, but the resulting signal-to-noise ratio on emission nebulae is much higher.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eAre the filters in the Baader Narrowband Set parfocal?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, all filters in the Baader 3.5nm\/4nm set are designed to be \u003cstrong\u003eparfocal\u003c\/strong\u003e. This means you can switch between the H-alpha, O-III, and S-II filters in your filter wheel without having to adjust your focuser. This is a significant time-saver, especially for automated imaging runs.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill I need to refocus my Celestron EdgeHD 8\" when switching between the H-alpha and O-III filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, you should not need to refocus. The Baader 3.5nm\/4nm filters are parfocal, so once you achieve sharp focus with one filter (e.g., H-alpha), the O-III and S-II filters will be in the same focal plane. This holds true for any telescope system, including an 8\" EdgeHD SCT.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the 3.5nm H-alpha filter in this set to view solar prominences?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eAbsolutely not.\u003c\/strong\u003e This is extremely dangerous and will cause permanent blindness. A deep-sky H-alpha filter has a bandpass of 3.5nm (35 Ångströms). A safe, dedicated solar H-alpha filter has a bandpass of less than 0.1nm (1 Ångström). This filter lets in thousands of times more energy and is not designed for solar use in any capacity.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eI'm imaging the Pelican Nebula (IC 5070) from a Bortle 7 zone. Will this filter set help?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this set is ideal for that scenario. The ultra-narrow 3.5nm and 4nm bandpasses are extremely effective at isolating the specific wavelengths of light from the Pelican Nebula (IC 5070) while aggressively rejecting the broadband light pollution typical of a Bortle 7 zone. You will be able to capture high-contrast data that would be impossible with broadband or wider narrowband filters from that location.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003e3-Filter Narrowband Set (H-alpha, O-III, S-II)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-alpha Bandpass\u003c\/td\u003e\n\u003ctd\u003e3.5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eO-III Bandpass\u003c\/td\u003e\n\u003ctd\u003e4nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eS-II Bandpass\u003c\/td\u003e\n\u003ctd\u003e3.5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDesign\u003c\/td\u003e\n\u003ctd\u003eCMOS-Optimized, Parfocal\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Formats\u003c\/td\u003e\n\u003ctd\u003e1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted, 36mm Round Unmounted, 50.4mm Round Unmounted, 50x50mm Square, 65x65mm Square\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.02 (1.25\" Round Mounted)\u003cbr\u003e0.04 (2\" Round Mounted, 50.4mm Round Unmounted Filter)\u003cbr\u003e0.01 (31mm Round Unmounted Filter, 36mm Round Unmounted Filter)\u003cbr\u003e0.06 (50x50mm Square Filter)\u003cbr\u003e0.10 (65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter shape\u003c\/td\u003e\n\u003ctd\u003eround (1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted Filter, 36mm Round Unmounted Filter, 50.4mm Round Unmounted Filter)\u003cbr\u003esquare (50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSingle or Set?\u003c\/td\u003e\n\u003ctd\u003eFilter-Set\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter mounted\u003c\/td\u003e\n\u003ctd\u003eMounted (LPFC 6mm) (1.25\" Round Mounted, 2\" Round Mounted)\u003cbr\u003eUnmounted (31mm Round Unmounted Filter, 36mm Round Unmounted Filter, 50.4mm Round Unmounted Filter, 50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eCMOS, CCD, H-alpha, O-III, S-II\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpecial Features\u003c\/td\u003e\n\u003ctd\u003eCMOS-optimized with Life-Coat™\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thickness (without cell)\u003c\/td\u003e\n\u003ctd\u003e2 mm (1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted Filter, 36mm Round Unmounted Filter)\u003cbr\u003e3 mm (50.4mm Round Unmounted Filter, 50x50mm Square Filter, 65x65mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCWL (Central Wavelength)\u003c\/td\u003e\n\u003ctd\u003e656.3 nm \/ 500.7 nm \/ 671.7 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003eReflex-Blocker™ hard coated, planeoptically polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSuitable for f\/ratio\u003c\/td\u003e\n\u003ctd\u003e\u0026gt; f\/3.4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_Filter_Problems_FAQ_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium Filter Problems FAQ Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_Narrowband_Filters_on_Astronomical_Telescopes_Whitepaper.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium Narrowband Filters on Astronomical Telescopes Whitepaper\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/baader-planetarium-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eBaader Planetarium Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"1.25\" Round Mounted","offer_id":44967948878109,"sku":"BAA-2961670","price":1126.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967948910877,"sku":"BAA-2961673","price":1635.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted Filter","offer_id":44967948943645,"sku":"BAA-2961671","price":1197.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted Filter","offer_id":44967948976413,"sku":"BAA-2961672","price":1440.0,"currency_code":"CAD","in_stock":true},{"title":"50.4mm Round Unmounted Filter","offer_id":44967949009181,"sku":"BAA-2961674","price":1769.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Filter","offer_id":44967949041949,"sku":"BAA-2961675","price":1886.0,"currency_code":"CAD","in_stock":true},{"title":"65x65mm Square Filter","offer_id":44967949074717,"sku":"BAA-2961676","price":2451.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Baader-Narrowband-Filter-Set-H-a-7nm-OIII-8-5nm-SII-8nm-1__77412.1597110943.1280.1280__93547.1639085821.1280.1280.jpg?v=1684347232"},{"product_id":"optolong-l-ultimate-filter","title":"Optolong L-Ultimate Ha\/OIII 3nm Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDual 3nm bandpass isolates Hydrogen-alpha and Oxygen-III emission lines\u003c\/li\u003e\n\u003cli\u003eBlocks light pollution across the 300-1000nm spectrum\u003c\/li\u003e\n\u003cli\u003eGreater than OD4 blocking of unwanted wavelengths\u003c\/li\u003e\n\u003cli\u003eλ\/4 transmitted wavefront for sharp, high-resolution images\u003c\/li\u003e\n\u003cli\u003ePrecision 60\/40 surface quality optical glass substrate\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong L-Ultimate Ha\/OIII 3nm Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong L-Ultimate Ha\/OIII 3nm Filter isolates critical nebula emission lines with an extremely narrow 3nm full width at half maximum (FWHM) for both its H-alpha and OIII channels. This filter achieves its deep-sky contrast by implementing greater than OD4 blocking across a wide 300-1000nm range, effectively eliminating light pollution from urban and suburban skies. Each filter is manufactured to a λ\/4 transmitted wavefront standard, ensuring that the filter itself does not degrade the resolution of your optical system.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eDual 3nm Bandpass for Maximum Nebula Contrast\u003c\/h3\u003e\n\u003cp\u003eBy restricting the incoming light to only the H-alpha (656nm) and OIII (500nm) emission lines within a tight 3nm window, the L-Ultimate filter dramatically increases the signal-to-noise ratio of emission nebulae. This surgical isolation means that the faint, intricate structures within targets like the Squid Nebula (OU4) or supernova remnants are captured with stark contrast against a near-black sky background. The result is an image with significantly more \"pop\" and detail compared to what is possible with broader-band filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e\u0026gt;OD4 Blocking for Urban Imaging\u003c\/h3\u003e\n\u003cp\u003eFor astrophotographers working under light-polluted skies, the L-Ultimate's primary function is its aggressive rejection of unwanted artificial and natural light. With a blocking efficiency rated at an optical density greater than 4 (\u0026gt;OD4), it effectively nullifies the glow from mercury vapor, high and low-pressure sodium streetlights, and the natural atmospheric airglow. This level of suppression allows you to capture clean, long-exposure data from even the most challenging urban environments, turning previously unfruitful nights into productive imaging sessions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eλ\/4 Optics and Advanced Ion Coatings\u003c\/h3\u003e\n\u003cp\u003eOptolong builds the L-Ultimate filter on an optical glass substrate polished to a 60\/40 surface quality and a transmitted wavefront of λ\/4, preserving the sharpness of your telescope's optics. The filter's dielectric coatings are applied using an advanced ion-assisted deposition process, which creates a durable, scratch-resistant surface. This modern coating technique also ensures the central wavelength of the bandpass remains stable and does not drift with temperature changes, providing consistent results from night to night.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eL-Ultimate vs. L-eXtreme \u0026amp; L-eNhance: Why 3nm Matters\u003c\/h3\u003e\n\u003cp\u003eWhile filters like the Optolong L-eXtreme and L-eNhance are effective dual-band filters, the L-Ultimate distinguishes itself with its much narrower 3nm bandpasses. This tighter specification provides several key advantages for specific imaging goals.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDarker Sky Background:\u003c\/strong\u003e The 3nm window passes less of the skyglow continuum and blocks more of the light from stars, leading to a darker overall background and enhanced nebula contrast.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBetter Star Suppression:\u003c\/strong\u003e By collecting less stellar light outside the core emission lines, stars appear smaller and less prominent, allowing the faint nebulosity to dominate the image.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrade-Off:\u003c\/strong\u003e The primary limitation is that its tight bandpass is not well-suited for very fast optical systems (typically f\/4 and faster), where significant band-shift can occur. For these systems, a broader filter like the L-eXtreme may be more appropriate.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main difference between the Optolong L-Ultimate and the L-eXtreme filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary difference is the bandpass width. The \u003cstrong\u003eL-Ultimate uses a very narrow 3nm bandpass\u003c\/strong\u003e for both H-alpha and OIII, while the L-eXtreme uses a wider 7nm bandpass. The L-Ultimate's 3nm design provides a darker sky background and better star control, maximizing contrast on emission nebulae, but it is less suited for very fast telescopes.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong L-Ultimate filter with a DSLR or a color astronomy camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the L-Ultimate is specifically designed for use with one-shot color cameras like DSLRs and dedicated color CMOS\/CCD cameras. It passes both the red H-alpha and blue-green OIII light simultaneously, allowing you to capture a detailed, color-rich image of emission nebulae in a single set of exposures.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is the Optolong L-Ultimate not recommended for fast telescopes (f\/4 and faster)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eExtremely narrow filters like the L-Ultimate can experience \"band-shift\" when used with fast optical systems. The steep light cone from a fast telescope causes the filter's central wavelength to shift away from the intended emission line for off-axis light rays. This can result in a loss of signal. For telescopes f\/4 or faster, a filter with a slightly wider bandpass, like 7nm, is often a better choice to avoid this effect.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Optolong L-Ultimate perform on a target like the Veil Nebula (NGC 6960) from a city?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe L-Ultimate is ideal for this scenario. The Veil Nebula is rich in both H-alpha and OIII, and the filter's dual 3nm bandpasses will isolate this signal while its \u0026gt;OD4 blocking rejects the city light pollution. You can expect to capture the delicate, filamentary structure of the nebula with high contrast against a dark background, even from a heavily light-polluted site.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong L-Ultimate a good choice for my 8\" f\/10 SCT?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, an f\/10 Schmidt-Cassegrain Telescope is an excellent match for the L-Ultimate filter. Slower optical systems like SCTs do not cause the band-shift issues seen in fast refractors or Newtonians. The filter will work at its peak efficiency, delivering maximum contrast and light pollution suppression for imaging emission nebulae.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the Optolong L-Ultimate filter work on galaxies or reflection nebulae?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this filter is not designed for broadband targets. Galaxies like Andromeda (M31) and reflection nebulae like the Pleiades (M45) shine by reflecting starlight across the entire visible spectrum. The L-Ultimate blocks almost all of this light, so these objects would be rendered extremely faint or invisible. It is exclusively for emission nebulae that glow at the specific H-alpha and OIII wavelengths.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eFWHM\u003c\/td\u003e\n\u003ctd\u003eOIII 3nm, H-alpha 3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eOptical Glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Range\u003c\/td\u003e\n\u003ctd\u003e300-1000nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Efficiency\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;OD4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront RMS\u003c\/td\u003e\n\u003ctd\u003eλ\/4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30 arcseconds\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eOptolong L-Ultimate Ha\/OIII 3nm Filter with Protective Case\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":50286466203933,"sku":"OPT-11601","price":404.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":44968046559517,"sku":"OPT-11602","price":545.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Optolong-L-Ultimate-2-inch-2__17268.1665168471.1280.1280.jpg?v=1684348283"},{"product_id":"antlia-3nm-narrowband-h-alpha-pro-filter","title":"Antlia 3nm Narrowband H-alpha Pro Filter","description":"\u003cul\u003e\n  \u003cli\u003e656.3nm H-alpha Central Wavelength\u003c\/li\u003e\n  \u003cli\u003eSmall 3nm FHWM\u003c\/li\u003e\n  \u003cli\u003eHigh \u0026gt;88% Peak Transmission\u003c\/li\u003e\n  \u003cli\u003eMinimized halos on bright stars\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cp\u003eIntroducing the Antlia 3nm H-Alpha Pro Filter, the pinnacle of precision for narrowband astrophotography. Engineered to feature a Full Width Half Maximum (FWHM) of just 3nm, this filter dramatically enhances the contrast of emission targets by significantly reducing unwanted background signals. Designed for astrophotographers aiming to capture detailed structures within nebulae, the Antlia H-Alpha 3nm Pro achieves an impressive 88% transmission at the 656.3nm hydrogen-alpha line, ensuring you capture the maximum signal for vivid, well-defined images.\u003c\/p\u003e\n\u003cp\u003eThe Antlia 3nm H-Alpha Pro is optimized for both long focal ratios and fast optical systems, maintaining high transmittance with minimal signal loss even in setups as fast as f\/3. This adaptability is bolstered by blue-shift data that confirms compatibility with high-speed systems like Hyperstar and RASA without sacrificing quality. Its exceptional out-of-band blocking, rated at OD5 (0.001%), provides outstanding signal-to-noise ratio and effectively minimizes interference from other wavelengths, sharpening each capture.\u003c\/p\u003e\n\u003ch3\u003eFeatures\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSteep Spectral Profile\u003c\/strong\u003e: Minimizes halos around bright stars, enhancing clarity and detail.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSingle Substrate Design\u003c\/strong\u003e: Eliminates internal reflections, ensuring pure and crisp images.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVersatile Application\u003c\/strong\u003e: Ideal for capturing H-alpha emission nebulae, planetary nebulae, Wolf-Rayet nebulae, and supernova remnants. It performs superbly in both light-polluted areas and dark sites, extending imaging opportunities even when the moon is up.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEdge Blackening\u003c\/strong\u003e: All filters are edge blackened to eliminate internal reflections from stray light, further improving image quality.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptical Precision\u003c\/strong\u003e: Built on a Schott optical substrate with a surface quality of 60\/40 (scratch\/dig), a transmitted wavefront of Lambda\/4 or better, and parallelism less than 30 arcseconds, it meets stringent standards for optical performance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eHowever, it's important to note that the Antlia 3nm H-Alpha Pro filter is specifically tailored for deep sky objects that emit in the hydrogen-alpha line and will not be suitable for objects without H-alpha emissions.\u003c\/p\u003e\n\u003cp\u003eWith its superior design and technological advancements, the Antlia 3nm H-Alpha Pro Filter is an indispensable tool for astrophotographers seeking to push the boundaries of what's visible in the night sky.\u003c\/p\u003e\n\u003cdiv class=\"warning\"\u003e\n\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/warning-logo.svg?%0Av=1714663206\" alt=\"Disclaimer\" width=\"25px\"\u003e\n\u003cp\u003eThis filter is not suitable for solar observation or imaging. H-alpha filters designed for solar applications are significantly narrower and specifically engineered to handle the intense light from the sun. Attempting to use this deep sky astrophotography filter for observing or imaging the sun can result in severe damage to your equipment and pose serious risk of eye injury or blindness. Always ensure that you are using the correct type of filter for solar observation to protect both yourself and your equipment.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003eBasic Substrate\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003eSchott optical substrate\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003eFilter Thickness\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003e2mm+\/-0.05mm\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003eFWHM (Full width at half maximum)\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003e3nm\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003eCWL (Central Wavelength)\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003e656.3nmnm\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003ePeak Transmission\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003e＞88%\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003eBlocking\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003e\u0026gt; 5 OD(0.001% out of band blocking) @ 300-1000nm\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003eSurface Quality\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003eS\/D (scratch\/dig)= 60\/40 (Refer to MIL-O-13830)\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003eTransmitted Wavefront\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003eLambda\/4 or better.\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003eParallelism\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003eLess than 30 arcsec\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003eSubstrate\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003eSingle \/ Non-glued\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul\u003e\n\u003cli\u003eFilter\u003c\/li\u003e\n\u003cli\u003eFilter Case\u003c\/li\u003e\n\u003cli\u003eTransmission graph\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Antlia","offers":[{"title":"1.25\" Mounted","offer_id":44968069824797,"sku":"ANT-HA-3NM-1.25","price":362.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Unmounted","offer_id":44968069857565,"sku":"ANT-HA-3NM-RD31","price":391.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Unmounted","offer_id":44968069890333,"sku":"ANT-HA-3NM-RD36","price":440.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":44968069923101,"sku":"ANT-HA-3NM-2","price":561.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Unmounted","offer_id":44968069955869,"sku":"ANT-HA-3NM-RD50","price":696.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Antlia-Ha-Pro__26276.1670360748.1280.1280.jpg?v=1770824812"},{"product_id":"antlia-3nm-narrowband-oiii-pro-filter","title":"Antlia 3nm Narrowband OIII Pro Filter","description":"\u003c!-- more --\u003e\u003cp\u003e\u003cspan\u003eAntlia OIII Pro narrowband filter optimizes the FWHM (full width half maximum) to 3nm\u003c\/span\u003e\u003cspan\u003e\u003cins cite=\"mailto:Ted%20Dobosz\" datetime=\"2021-01-06T13:06\"\u003e\u003c\/ins\u003e\u003c\/span\u003e\u003cspan\u003ebandpass\u003c\/span\u003e\u003cspan\u003e. \u003c\/span\u003e\u003cspan\u003eAs the bandwidth becomes narrower, the 3nm Pro narrowband filters enhance contrast of emission targets by lowering the unwanted background signal. Antlia \u003c\/span\u003e\u003cspan\u003eOIII\u003c\/span\u003e\u003cspan\u003e 3nm Pro filter\u003c\/span\u003e\u003cspan\u003es\u003c\/span\u003e\u003cspan\u003e\u003c\/span\u003e\u003cspan\u003eare\u003c\/span\u003e\u003cspan\u003e designed to deliver \u003c\/span\u003e\u003cspan\u003e85\u003c\/span\u003e\u003cspan\u003e% transmission at the 500.7nm line which provides you with the maximum signal and well defined nebulae structures.\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eConventional broader narrowband filters cause a heavy loss in transmission due to the strong Center Wavelength (CWL)\u003c\/span\u003e\u003cspan\u003e\u003c\/span\u003e\u003cspan\u003eshift\u003c\/span\u003e\u003cspan\u003e.\u003c\/span\u003e\u003cspan\u003e We guarantee T\u0026gt;\u003c\/span\u003e\u003cspan\u003e85\u003c\/span\u003e\u003cspan\u003e% within 1nm range of the center bandwidth, which means that the 3nm Pro narrowband filter can guarantee high transmittance for working with both long focal ratios and fast optical systems. \u003c\/span\u003e\u003cspan\u003eB\u003c\/span\u003e\u003cspan\u003elue\u003c\/span\u003e\u003cspan\u003e\u003c\/span\u003e\u003cspan\u003eshift data shows that Antlia 3nm Pro filters can be used with nearly all systems as fast as f\/3 with minimal\u003c\/span\u003e\u003cspan\u003e\u003c\/span\u003e\u003cspan\u003eloss in emission signal and meets the requirements of fast optics like Hyperstar and RASA.\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eThe out of band blocking specification is rated OD\u003c\/span\u003e\u003cspan\u003e5\u003c\/span\u003e\u003cspan\u003e (0.\u003c\/span\u003e\u003cspan\u003e00\u003c\/span\u003e\u003cspan\u003e1%) which delivers an excellent \u003c\/span\u003e\u003cspan\u003eSNR(\u003c\/span\u003e\u003cspan\u003esignal to noise ratio\u003c\/span\u003e\u003cspan\u003e)\u003c\/span\u003e\u003cspan\u003e and effective cut\u003c\/span\u003e\u003cspan\u003e\u003c\/span\u003e\u003cspan\u003eoff rate to minimize interference from other wavelengths.\u003c\/span\u003e\u003cspan\u003e\u003c\/span\u003e\u003cspan\u003eImproved sharp cut\u003c\/span\u003e\u003cspan\u003e\u003c\/span\u003e\u003cspan\u003eoff astrophotography 3nm Pro filters are designed to minimize halos around bright stars.\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eApplication and Performance:\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eHigh transmittance and smallest bandwidth\u003c\/span\u003e\u003cspan\u003e to maximize\u003c\/span\u003e\u003cspan\u003e contrast\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eSteep spectral profile minimizes halos around bright stars\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eA single substrate to eliminate internal reflections   \u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eNarrowband Objects: OIII Emission Nebulae, Planetary, Wolf Rayet Nebulae and Supernova Remnants\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eUse in light polluted areas and dark sites\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eExtend\u003c\/span\u003e\u003cspan\u003es\u003c\/span\u003e\u003cspan\u003e\u003c\/span\u003e\u003cspan\u003eimaging time when the moon is up\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eAntlia narrowband Pro filters can be used \u003c\/span\u003e\u003cspan\u003edown \u003c\/span\u003e\u003cspan\u003eto F\/3\u003c\/span\u003e\u003cspan\u003e systems\u003c\/span\u003e\u003cspan\u003e with slight loss of signal\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eAll A\u003c\/span\u003e\u003cspan\u003entlia\u003c\/span\u003e\u003cspan\u003e Narrowband filters are edge blackened to \u003c\/span\u003e\u003cspan\u003eeliminate internal reflections\u003c\/span\u003e\u003cspan\u003e from stray light\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eSuperior optical reliability reduces \u003c\/span\u003e\u003cspan\u003epost image processing\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eThis filter is not suited to deep sky objects that do not contain OIII emissions.\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eTechnical Specifications\u003c\/span\u003e\u003cspan\u003e:\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBasic Substrate:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e optical substrate\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eFilter Thickness:   \u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e2mm+\/-0.05mm for \u003c\/span\u003e\u003cspan\u003e2'' \u003c\/span\u003e\u003cspan\u003emounted\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eFWHM (Full width at half maximum): \u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e3nm\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eCWL (Central Wavelength)\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e: 500.7nm\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003ePeak Transmission:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e ＞85%\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBlocking: \u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e\u0026gt; 5 OD(0.001% out of band blocking) @ 300-1000nm\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eSurface Quality: \u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003eS\/D (scratch\/dig)= 60\/40 (Refer to MIL-O-13830)\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eTransmitted Wavefront: \u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003eLambda\/4 or better.\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eParallelism: \u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003eless than 30 arcsec\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eSingle \/ Non-glued substrate\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eWarranty: 3-years against delamination\u003c\/span\u003e\u003c\/p\u003e","brand":"Antlia","offers":[{"title":"1.25\" Mounted","offer_id":44968070054173,"sku":"ANT-OIII-3NM-1.25","price":362.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Unmounted","offer_id":44968070086941,"sku":"ANT-OIII-3NM-RD31","price":391.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Unmounted","offer_id":44968070119709,"sku":"ANT-OIII-3NM-RD36","price":440.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":44968070152477,"sku":"ANT-OIII-3NM-2","price":561.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Unmounted","offer_id":44968070185245,"sku":"ANT-OIII-3NM-RD50","price":696.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Antlia-OIII-Pro__82794.1670360959.1280.1280.jpg?v=1684348664"},{"product_id":"antlia-3nm-narrowband-sii-pro-filter","title":"Antlia 3nm Narrowband SII Pro Filter","description":"\u003c!-- more --\u003e\u003cp\u003e\u003cspan\u003eAntlia \u003c\/span\u003e\u003cspan\u003eSII \u003c\/span\u003e\u003cspan\u003ePro narrowband filter optimizes the FWHM (full width half maximum) to 3nm bandpass. As the bandwidth becomes narrower, the \u003c\/span\u003e\u003cspan\u003e3nm \u003c\/span\u003e\u003cspan\u003ePro \u003c\/span\u003e\u003cspan\u003enarrowband \u003c\/span\u003e\u003cspan\u003efilters enhance contrast of emission targets by lowering the unwanted background signal. Antlia SII\u003c\/span\u003e\u003cspan\u003e 3nm Pro\u003c\/span\u003e\u003cspan\u003e filter is designed to deliver 88% transmission at the 671.6nm line\u003c\/span\u003e\u003cspan\u003e which\u003c\/span\u003e\u003cspan\u003e provides you with the maximum signal and well defined nebulae structures\u003c\/span\u003e\u003cspan\u003e.\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eConventional broader narrowband filters cause a heavy loss in transmission due to the strong (Center Wavelength (CWL)-shift\u003c\/span\u003e\u003cspan\u003e. \u003c\/span\u003e\u003cspan\u003eWe guarantee T\u0026gt;88% within 1nm range of the center bandwidth\u003c\/span\u003e\u003cspan\u003e,\u003c\/span\u003e\u003cspan\u003ewhich means that the 3nm Pro narrowband filter can guarantee high transmittance for working with both long focal ratios and fast optical systems\u003c\/span\u003e\u003cspan\u003e. B\u003c\/span\u003e\u003cspan\u003elue\u003c\/span\u003e\u003cspan\u003e-\u003c\/span\u003e\u003cspan\u003eshift data show that Antlia 3nm Pro filters can be used with nearly all systems as fast as f\/3 with minimal loss in emission signal\u003c\/span\u003e\u003cspan\u003e\u003c\/span\u003e\u003cspan\u003eand meets the requirements of fast optics like Hyperstar and RASA.\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eThe out of band blocking specification is rated OD\u003c\/span\u003e\u003cspan\u003e5\u003c\/span\u003e\u003cspan\u003e (0.\u003c\/span\u003e\u003cspan\u003e00\u003c\/span\u003e\u003cspan\u003e1%) which delivers an excellent \u003c\/span\u003e\u003cspan\u003eSNR(\u003c\/span\u003e\u003cspan\u003esignal to noise ratio\u003c\/span\u003e\u003cspan\u003e)\u003c\/span\u003e\u003cspan\u003e and effective cut-off rate to minimize interference from other wavelengths.\u003c\/span\u003e\u003cspan\u003e\u003c\/span\u003e\u003cspan\u003eImproved\u003c\/span\u003e\u003cspan\u003e sharp cut-off\u003c\/span\u003e\u003cspan\u003e astrophotography 3nm Pro filters are designed to minimize halos around bright stars.\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eApplication and Performance:\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eHigh transmittance and smallest bandwidth\u003c\/span\u003e\u003cspan\u003e to maximize\u003c\/span\u003e\u003cspan\u003e contrast\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eSteep spectral profile minimizes halos around bright stars\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eA single substrate to eliminate internal reflections   \u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eNarrowband Objects: SII Emission Nebulae, Planetary, Wolf-Rayet Nebulae and Supernova Remnants\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eUse in light polluted areas and dark sites\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eExtend imaging time when the moon is up\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eAll Antlia narrowband Pro filters can be used \u003c\/span\u003e\u003cspan\u003edown \u003c\/span\u003e\u003cspan\u003eto F\/3 with slight loss of signal\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eAll Antlia Narrowband filters are edge blackened to eliminate internal reflections from stray light\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eSuperior optical reliability reduces post image processing\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eThis filter is not suited to deep sky objects that do not contain \u003c\/span\u003e\u003cspan\u003eSII\u003c\/span\u003e\u003cspan\u003e emissions.\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eTechnical Specifications\u003c\/span\u003e\u003cspan\u003e:\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBasic Substrate:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Schott optical substrate\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eFilter Thickness： \u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e2\u003c\/span\u003e\u003cspan\u003emm+\/-0.05mm for Dia36mm unmounted\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eFWHM (Full width at half maximum): \u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e3nm\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eCWL (Central Wavelength)\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e: 671.6nm\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003ePeak Transmission:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e ＞88%\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eBlocking: \u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e\u0026gt; 5 OD(0.001% out of band blocking) @ 300-1000nm\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eSurface Quality: \u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003eS\/D (scratch\/dig)= 60\/40 (Refer to MIL-O-13830)\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eTransmitted Wavefront: \u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003eLambda\/4 or better.\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eParallelism: \u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003eless than 30 arcsec\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eSingle \/ Non-glued substrate\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan\u003eWarranty: 3-years against delamination\u003c\/span\u003e\u003c\/p\u003e","brand":"Antlia","offers":[{"title":"1.25\" Mounted","offer_id":44968070218013,"sku":"ANT-SII-3NM-1.25","price":362.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Unmounted","offer_id":44968070250781,"sku":"ANT-SII-3NM-RD31","price":391.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Unmounted","offer_id":44968070283549,"sku":"ANT-SII-3NM-RD36","price":440.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":44968070316317,"sku":"ANT-SII-3NM-2","price":561.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Unmounted","offer_id":44968070349085,"sku":"ANT-SII-3NM-RD50","price":696.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Antlia-SII-Pro__65220.1670361127.1280.1280.jpg?v=1684348641"},{"product_id":"antlia-triband-rgb-ultra-filter","title":"Antlia Triband RGB Ultra Filter V2","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eEnhanced Transmission for Superior Signal-to-Noise Ratio\u003c\/li\u003e\n\u003cli\u003eAnti-Reflection Coating to Reduce Halo Effect\u003c\/li\u003e\n\u003cli\u003eOptimized for Fast Optics up to f\/2\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003c!-- Title image text --\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003c!-- Main Image --\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eAntlia Triband RGB Ultra Filter V2 - Overview\u003c\/h2\u003e\n\u003cimg class=\"DAV-img-banner\" alt=\"Antlia Triband RGB Ultra Filter V2\" src=\"https:\/\/davidastro.com\/cdn\/shop\/products\/ANT-TRI-RGB-2__19119.1677769060.1280.1280_936x936.jpg\"\u003e\n\u003cp\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- Features Grid --\u003e\n\u003cdiv class=\"DAV-feature-grid\"\u003e\n\u003c!-- Feature Box 1 --\u003e\n\u003cdiv class=\"DAV-feature-box\"\u003e\n\u003ch3\u003eHigh Signal-to-Noise Ratio\u003c\/h3\u003e\n\u003cp\u003eSuperior imaging in challenging light conditions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c!-- Feature Box 2 --\u003e\n\u003cdiv class=\"DAV-feature-box\"\u003e\n\u003ch3\u003eVersatile Applications\u003c\/h3\u003e\n\u003cp\u003eDesigned for light pollution suppression for OSC and Mono cameras.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c!-- Feature Box 3 --\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-section-container\"\u003e\n\u003cdiv class=\"DAV-section-text\"\u003e\n\u003ch3\u003eAntlia Triband RGB Ultra Filter V2 Filter\u003c\/h3\u003e\n\u003cp\u003eIt is designed for light pollution suppression for OSC and Mono cameras. The spectral design selected the most substantial information in the RGB bands, which makes Antlia Triband RGB Ultra Filter possible to shoot over 90% of deep sky objects, in addition to its excellent performance on emission nebula, different from other ultra-narrowband filters, it is able to capture galaxies, reflection nebulae, and star clusters from a Bortle 8 location to Bortle 1 while presenting more balanced RGB colors in your images. Also, it has a broad bandpass designed to cope with faster optics up to the f\/2 focal ratio. \u003cbr\u003eThe quantum efficiency of the B channel in current CMOS sensors is often significantly lower than that of R and G channels. Antlia team was to provide a filter with a more realistic color balance for astrophotography from light polluted locations. The problem with the low blue wavelength efficiency becomes apparent when imaging reflection nebulae and blue stars. In CMOS sensors, the blue wavelengths also contain contribution from the stronger green spectrum, thereby affecting the balance of the blue colours. Many popular imaging objects contain reflection nebula with faint blue hues such the central part ofNGC2264. Therefore, we designed Antlia Triband RGB Ultra Filter that not only retains the HSO emission signal but alsoincreases the amount of Luminous flux of the blue B channel. By improving the blue wavelength transmission, the color of thephoto is better balanced and easier to manage in post processing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-section-img\"\u003e\u003cimg alt=\"Sii\u0026amp;Hb\" src=\"https:\/\/davidastro.com\/cdn\/shop\/products\/ANT-TRI-RGB-2__19119.1677769060.1280.1280_936x936.jpg\"\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ch2\u003eSII\u0026amp;Hβ 3.5nm Filter\u003c\/h2\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003eFWHM\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003e3.5mm\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003ePeak Transmission\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003e92% (Ha), 92% (Sii), 92% (Oiii), 92% (Nii)\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003eBlocking\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003e≥ OD4 (300-1100nm)\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003eRing Design\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cp\u003eUltra-thin and black anodized to minimize reflections\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cimg class=\"DAV-img-box\" alt=\"HaOIII\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/antlia-filter-3nm-ha-oiii-antlia-alp-t-dual-band-highspeed-3nm-ha-oiii-3-5nm-sii-hb-2-mounted-filters-42550623338715_1024x_67b5496f-f728-4fd1-b82a-563e5e8c9962.webp?v=1733252057\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eAntlia Triband RGB Ultra Filter V2 Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Antlia","offers":[{"title":"2\" Mounted","offer_id":44968075231517,"sku":"ANT-TRIBAND-V2","price":254.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/ANT-TRI-RGB-2__19119.1677769060.1280.1280.jpg?v=1684348732"},{"product_id":"askar-6nm-color-magic-ha-oiii-sii-oiii-d1-d2-filter-package","title":"Askar 6nm Colour Magic Ha\/OIII \u0026 SII\/OIII (D1+D2) Filter Package","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e6nm Dual-Bandpass Filter Set\u003c\/li\u003e\n\u003cli\u003eIncludes D1 (Hα+OIII) and D2 (SII+OIII) Filters\u003c\/li\u003e\n\u003cli\u003eEnables SHO-like imaging with color cameras\u003c\/li\u003e\n\u003cli\u003eHigh contrast for light-polluted skies\u003c\/li\u003e\n\u003cli\u003eExcellent halo control around bright stars\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eAskar 6nm Colour Magic Ha\/OIII \u0026amp; SII\/OIII (D1+D2) Filter Package\u003c\/h2\u003e\n\u003cp\u003eThe Askar 6nm Colour Magic Filter Package uses a tight 6nm bandpass to capture stunning narrowband images with your color camera. This innovative set includes two filters: a 6nm D1 (Hα\/OIII) and a 6nm D2 (SII\/OIII), designed to work together to isolate the three most critical emission nebula wavelengths without requiring a monochrome camera.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eA 2-Filter System for 3-Band Narrowband Imaging\u003c\/h3\u003e\n\u003cp\u003eThis package redefines narrowband imaging for one-shot-color (OSC) camera users by splitting the data acquisition across two specialized filters. The first filter, D1, captures Hydrogen-alpha and Oxygen-III, the dominant signals in most emission nebulae. The second filter, D2, captures Sulphur-II and Oxygen-III, adding the final dataset needed for creating images with the celebrated \"Hubble Palette\" color scheme.\u003c\/p\u003e\n\u003cp\u003eBy capturing data through these two filters and combining the results during processing, you can produce detailed, multi-wavelength images that were previously the exclusive domain of more complex monochrome setups. This approach simplifies the imaging process while still delivering rich, high-contrast results.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e6nm Bandpass: Maximum Contrast and Halo Control\u003c\/h3\u003e\n\u003cp\u003eThe 6nm bandpass on each filter is engineered to aggressively reject unwanted light from urban light pollution, moonlight, and natural skyglow. This extreme signal isolation dramatically increases the contrast between your nebula target and the background sky, revealing faint structures and details that would otherwise be lost. \u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-Sky from the City:\u003c\/strong\u003e The narrow 6nm window allows you to capture high-quality deep-sky data even from heavily light-polluted locations.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHalo Suppression:\u003c\/strong\u003e Askar's design provides excellent control of halos around bright stars, a common issue with narrowband filters. This ensures clean star profiles and preserves the integrity of your target.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFast Optics Ready:\u003c\/strong\u003e While not designed exclusively for high-speed systems, these filters have been tested to perform well with modern, fast astrographs, maintaining signal strength and star quality.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eAskar Duo-Filter vs. Mono Imaging: A New Workflow for Color Cameras\u003c\/h3\u003e\n\u003cp\u003eThe Colour Magic filter set offers a compelling alternative to the traditional monochrome imaging workflow. While a mono camera with a filter wheel provides the highest level of control, the Askar D1+D2 package delivers a significant portion of that capability with far less complexity and cost.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eYour Advantage (Askar D1+D2):\u003c\/strong\u003e You use the color camera you already own. Data acquisition is simplified to just two sessions (one for each filter), and processing is more straightforward than combining separate L, R, G, B, H, S, and O channels.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe Mono Advantage:\u003c\/strong\u003e A monochrome setup allows for capturing data through each channel separately, offering maximum flexibility in processing and the ability to optimize exposure times for each emission line. This is a more involved, but ultimately more powerful, process.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eFor the OSC imager looking to step into the world of narrowband without investing in a full mono rig, the Askar Colour Magic package is the ideal solution.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Askar 6nm Colour Magic filter set work with a one-shot-color camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYou take two sets of exposures: one with the \u003cstrong\u003eD1 (Hα+OIII) filter\u003c\/strong\u003e and another with the \u003cstrong\u003eD2 (SII+OIII) filter\u003c\/strong\u003e. In processing software, you can separate the color channels from each set of images. The red channel from the D1 data contains your Hα signal, the red channel from D2 contains your SII, and the green\/blue channels from both contain your OIII. This allows you to combine them into a full SHO (Hubble Palette) image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the purpose of having OIII on both the Askar D1 and D2 filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eCapturing Oxygen-III signal with both filters ensures you gather a very strong and clean OIII dataset. This is beneficial because OIII is often a weaker signal than H-alpha. Having it present in both master files gives you more flexibility and higher signal-to-noise ratio when processing your final image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use just the Askar 6nm D1 (Hα+OIII) filter by itself?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. The D1 filter on its own is a powerful dual-narrowband filter, excellent for capturing emission nebulae like the Orion Nebula (M42) or Lagoon Nebula (M8) in high contrast. Using it alone will produce images with characteristic red and blue\/teal hues, similar to other popular dual-band filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow would I use the Askar 6nm Colour Magic set to image the Eagle Nebula (M16) with my f\/5 refractor?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Pillars of Creation in the Eagle Nebula (M16) are a perfect target. First, capture a series of long exposures with the D1 filter to get your Hα and OIII data. Then, swap to the D2 filter and capture another series of exposures to get your SII data. The 6nm bandpass will help define the intricate dark dust lanes against the glowing gas, even under moderately light-polluted skies with your f\/5 system.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Askar 6nm filters work well on the Cygnus Loop (NGC 6960) from my Bortle 7 backyard?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this is an ideal scenario for these filters. The Cygnus Loop (Veil Nebula complex) is rich in both Hα and OIII. The tight 6nm bandpass of the Askar filters will effectively block the strong light pollution from a Bortle 7 zone, allowing the delicate, filamentary structure of the supernova remnant to stand out with impressive contrast.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes this Askar 6nm filter set replace a traditional SHO filter set for mono cameras?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNot directly. This set is designed to give \u003cstrong\u003ecolor camera users\u003c\/strong\u003e access to SHO-like color palettes. A traditional SHO filter set for monochrome cameras offers more control over the individual signals and is still the standard for advanced imagers. The Askar Colour Magic set provides a simpler, more accessible workflow to achieve similar results without needing a mono camera and filter wheel.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eDual-Band Narrowband Filter Set\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandwidth\u003c\/td\u003e\n\u003ctd\u003e6nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter 1 (D1)\u003c\/td\u003e\n\u003ctd\u003eH-alpha \/ OIII\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter 2 (D2)\u003c\/td\u003e\n\u003ctd\u003eSulphur-II \/ OIII\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/www.sharpstar-optics.com\/download_list_1\/7.html\" target=\"_blank\"\u003e\u003csvg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 640 512\" class=\"DAV-img-box\"\u003e\u003cpath fill=\"#0047a7\" d=\"M128 32C92.7 32 64 60.7 64 96l0 256 64 0 0-256 384 0 0 256 64 0 0-256c0-35.3-28.7-64-64-64L128 32zM19.2 384C8.6 384 0 392.6 0 403.2C0 445.6 34.4 480 76.8 480l486.4 0c42.4 0 76.8-34.4 76.8-76.8c0-10.6-8.6-19.2-19.2-19.2L19.2 384z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eDownload Software \u0026amp; Drivers\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/askar-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eAskar 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Askar","offers":[{"title":"Default Title","offer_id":44968075297053,"sku":"ASK-CM-D1D2","price":875.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Askar-Color-Magic-D1-D2__81140.1678398625.1280.1280.jpg?v=1684348734"},{"product_id":"antlia-4-5nm-narrowband-h-alpha-edge-filter","title":"Antlia 4.5nm Narrowband H-alpha Edge Filter","description":"\u003c!-- more --\u003e\n\u003cp\u003eAntlia H-alpha EDGE narrowband filter optimizes the FWHM (full width half maximum) to 4.5nm bandpass. The suppression of optical density (OD)5 on unwanted wavelengths and the excellent transmittance characteristics found in the Antlia 3nm Pro series has been incorporated into the 4.5nm EDGE narrowband filters. The result is that these filters deliver superior SNR(signal to noise ratio) and better contrast in your images.\u003c\/p\u003e\n\u003cp\u003eAntlia H-alpha 4.5nm EGDE filters are designed to deliver high transmittance at the 656.3nm line that provides you with the maximum signal to reveal the faintest H-alpha nebulae structures.\u003c\/p\u003e\n\u003cp\u003eConventional broader narrowband filters cause a heavy loss in transmission due to the strong Center Wavelength (CWL)-shift. We guarantee T\u0026gt;90% within 1nm range of the center bandwidth, which means that the H-alpha 4.5nm EDGE narrowband filters can guarantee high transmittance for working with both long focal ratios and fast optical systems. Blue-shift data shows that Antlia 4.5nm EDGE filters can be used with nearly all systems as fast as f\/3 with minimal loss in emission signal and meets the requirements of fast optics.\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eApplication and Performance:\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003eHigh transmittance and narrow bandwidth to maximize contrast\u003c\/p\u003e\n\u003cp\u003eSteep spectral profile minimizes halos around bright stars\u003c\/p\u003e\n\u003cp\u003eA single substrate to eliminate internal reflections\u003c\/p\u003e\n\u003cp\u003eNarrowband Objects: H-alpha Emission Nebulae, Planetary, Wolf Rayet Nebulae and Supernova Remnants\u003c\/p\u003e\n\u003cp\u003eUse in light polluted areas and dark sites\u003c\/p\u003e\n\u003cp\u003eExtends imaging time when the moon is up\u003c\/p\u003e\n\u003cp\u003eAntlia narrowband EDGE filters can be used down to f\/3 systems with minimal loss of signal\u003c\/p\u003e\n\u003cp\u003eAll Antlia unmounted filters are edge blackened to eliminate internal reflections from stray light\u003c\/p\u003e\n\u003cp\u003eSuperior optical reliability reduces post image processing\u003c\/p\u003e\n\u003cp\u003eThis filter is only effective for deep sky objects that contain H-alpha emissions\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eTechnical Specifications:\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003eBasic Substrate: Optical, Single \/ Non-glued substrate\u003c\/p\u003e\n\u003cp\u003eFilter Thickness: 2mm+\/-0.05mm for 1.25”\u003c\/p\u003e\n\u003cp\u003eFWHM (Full width at half maximum): 4.5nm\u003c\/p\u003e\n\u003cp\u003eCWL (Central Wavelength): 656.3nm\u003c\/p\u003e\n\u003cp\u003ePeak Transmission:＞90% Blocking: \u0026gt; 5 OD (out of band blocking) @ 300-1000nm\u003c\/p\u003e\n\u003cp\u003eSurface Quality: S\/D (scratch\/dig)= 60\/40 (Refer to MIL-O-13830)\u003c\/p\u003e\n\u003cp\u003eTransmitted Wavefront: Lambda\/4 or better. Parallelism: less than 30 arcsec\u003c\/p\u003e","brand":"Antlia","offers":[{"title":"1.25\" Mounted","offer_id":45077796815133,"sku":"ANT-HA-4.5NM-1.25","price":263.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Unmounted","offer_id":45077796847901,"sku":"ANT-HA-4.5NM-RD31","price":277.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Unmounted","offer_id":45077796880669,"sku":"ANT-HA-4.5NM-RD36","price":320.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":45077796913437,"sku":"ANT-HA-4.5NM-2","price":412.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Unmounted","offer_id":45077796946205,"sku":"ANT-HA-4.5NM-RD50","price":497.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Antlia-4-5nm-H-alpha-Edge-Filter.jpg?v=1685809394"},{"product_id":"antlia-4-5nm-narrowband-oiii-edge-filter","title":"Antlia 4.5nm Narrowband OIII Edge Filter","description":"\u003c!-- more --\u003e\n\u003cp\u003eAntlia OIII EDGE narrowband filter optimizes the FWHM (full width half maximum) to 4.5nm bandpass. The suppression of optical density (OD)5 on unwanted wavelengths and the excellent transmittance characteristics found in the Antlia 3nm Pro series has been incorporated into the 4.5nm EDGE narrowband filters. The result is that these filters deliver superior SNR(signal to noise ratio) and better contrast in your images. Antlia OIII 4.5nm EDGE filters are designed to deliver 85% transmission at the 500.7nm line that provides you with the maximum signal to reveal the faintest OIII nebulae structures.\u003c\/p\u003e\n\u003cp\u003eConventional broader narrowband filters cause a heavy loss in transmission due to the strong Center Wavelength (CWL)-shift. We guarantee T\u0026gt;85% within 1nm range of the center bandwidth, which means that the OIII 4.5nm EDGE narrowband filters can guarantee high transmittance for working with both long focal ratios and fast optical systems. Blue-shift data shows that Antlia 4.5nm EDGE filters can be used with nearly all systems as fast as f\/3 with minimal loss in emission signal and meets the requirements of fast optics.\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eApplication and Performance: \u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003eHigh transmittance and narrow bandwidth to maximize contrast\u003c\/p\u003e\n\u003cp\u003eSteep spectral profile minimizes halos around bright stars\u003c\/p\u003e\n\u003cp\u003eA single substrate to eliminate internal reflections\u003c\/p\u003e\n\u003cp\u003eNarrowband Objects: OIII Emission Nebulae, Planetary, Wolf Rayet Nebulae and Supernova Remnants\u003c\/p\u003e\n\u003cp\u003eUse in light polluted areas and dark sites Extends imaging time when the moon is up\u003c\/p\u003e\n\u003cp\u003eAntlia narrowband EDGE filters can be used down to f\/3 systems with minimal loss of signal\u003c\/p\u003e\n\u003cp\u003eAll Antlia unmounted filters are edge blackened to eliminate internal reflections from stray light Superior optical reliability reduces post image processing\u003c\/p\u003e\n\u003cp\u003eThis filter is only effective for deep sky objects that contain OIII emissions\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eTechnical Specifications: \u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003eBasic Substrate: Optical, Single \/ Non-glued substrate\u003c\/p\u003e\n\u003cp\u003eFilter Thickness: 2mm+\/-0.05mm for 1.25''\u003c\/p\u003e\n\u003cp\u003eFWHM (Full width at half maximum): 4.5nm\u003c\/p\u003e\n\u003cp\u003eCWL (Central Wavelength): 500.7nm\u003c\/p\u003e\n\u003cp\u003ePeak Transmission: \u0026gt;85% Blocking: \u0026gt; 5 OD(0.001% out of band blocking) @ 300-1000nm\u003c\/p\u003e\n\u003cp\u003eSurface Quality: S\/D (scratch\/dig)= 60\/40 (Refer to MIL-O-13830)\u003c\/p\u003e\n\u003cp\u003eTransmitted Wavefront: Lambda\/4 or better. Parallelism: less than 30 arcsec\u003c\/p\u003e","brand":"Antlia","offers":[{"title":"1.25\" Mounted","offer_id":45077801632029,"sku":"ANT-OIII-4.5NM-1.25","price":263.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Unmounted","offer_id":45077801664797,"sku":"ANT-OIII-4.5NM-RD31","price":277.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Unmounted","offer_id":45077801697565,"sku":"ANT-OIII-4.5NM-RD36","price":320.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":45077801730333,"sku":"ANT-OIII-4.5NM-2","price":412.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Unmounted","offer_id":45077801763101,"sku":"ANT-OIII-4.5NM-RD50","price":497.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Antlia-4-5nm-OIII-Edge-Filter.jpg?v=1685809944"},{"product_id":"antlia-4-5nm-narrowband-sii-edge-filter","title":"Antlia 4.5nm Narrowband SII Edge Filter","description":"\u003c!-- more --\u003e\n\u003cp\u003eAntlia SII EDGE narrowband filter optimizes the FWHM (full width half maximum) to 4.5nm bandpass. The suppression of optical density (OD)5 on unwanted wavelengths and the excellent transmittance characteristics found in the Antlia 3nm Pro series has been incorporated into the 4.5nm EDGE narrowband filters. The result is that these filters deliver superior SNR(signal to noise ratio) and better contrast in your images.\u003c\/p\u003e\n\u003cp\u003eAntlia SII 4.5nm EGDE filters are designed to deliver high transmittance at the 671.6nm line that provides you with the maximum signal to reveal the faintest SII nebulae structures.\u003c\/p\u003e\n\u003cp\u003eConventional broader narrowband filters cause a heavy loss in transmission due to the strong Center Wavelength (CWL)-shift. We guarantee T\u0026gt;90% within 1nm range of the center bandwidth, which means that the SII 4.5nm EDGE narrowband filters can guarantee high transmittance for working with both long focal ratios and fast optical systems. Blue-shift data shows that Antlia 4.5nm EDGE filters can be used with nearly all systems as fast as f\/3 with minimal loss in emission signal and meets the requirements of fast optics.\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eApplication and Performance:\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003eHigh transmittance and narrow bandwidth to maximize contrast\u003c\/p\u003e\n\u003cp\u003eSteep spectral profile minimizes halos around bright stars\u003c\/p\u003e\n\u003cp\u003eA single substrate to eliminate internal reflections\u003c\/p\u003e\n\u003cp\u003eNarrowband Objects: SII Emission Nebulae, Planetary, Wolf-Rayet Nebulae and Supernova Remnants\u003c\/p\u003e\n\u003cp\u003eUse in light polluted areas and dark sites Extend imaging time when the moon is up\u003c\/p\u003e\n\u003cp\u003eAntlia narrowband EDGE filters can be used down to f\/3 systems with minimal loss of signal\u003c\/p\u003e\n\u003cp\u003eAll Antlia unmounted filters are edge blackened to eliminate internal reflections from stray light\u003c\/p\u003e\n\u003cp\u003eSuperior optical reliability reduces post image processing\u003c\/p\u003e\n\u003cp\u003eThis filter is only effective for deep sky objects that contain SII emissions\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eTechnical Specifications:\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003eBasic Substrate: Optical, Single \/ Non-glued substrate\u003c\/p\u003e\n\u003cp\u003eFilter Thickness: 2mm+\/-0.05mm for 1.25”\u003c\/p\u003e\n\u003cp\u003eFWHM (Full width at half maximum): 4.5nm\u003c\/p\u003e\n\u003cp\u003eCWL (Central Wavelength): 671.6nm\u003c\/p\u003e\n\u003cp\u003ePeak Transmission: ＞90%\u003c\/p\u003e\n\u003cp\u003eBlocking: \u0026gt; 5 OD(0.001% out of band blocking) @ 300-1000nm\u003c\/p\u003e\n\u003cp\u003eSurface Quality: S\/D (scratch\/dig)= 60\/40 (Refer to MIL-O-13830)\u003c\/p\u003e\n\u003cp\u003eTransmitted Wavefront: Lambda\/4 or better. Parallelism: less than 30 arcsec\u003c\/p\u003e","brand":"Antlia","offers":[{"title":"1.25\" Mounted","offer_id":45077809692957,"sku":"ANT-SII-4.5NM-1.25","price":263.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Unmounted","offer_id":45077809725725,"sku":"ANT-SII-4.5NM-RD31","price":277.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Unmounted","offer_id":45077809758493,"sku":"ANT-SII-4.5NM-RD36","price":320.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":45077809791261,"sku":"ANT-SII-4.5NM-2","price":412.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Unmounted","offer_id":45077809824029,"sku":"ANT-SII-4.5NM-RD50","price":497.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Antlia-4-5nm-SII-Edge-Filter.jpg?v=1685810048"},{"product_id":"antlia-alp-t-dualband-5nm-sii-hb-filter","title":"Antlia ALP-T Dualband 5nm SII\/Hb Filter","description":"\u003c!-- more --\u003e\n\u003cp\u003e\u003cspan\u003eThe ALP-T dual band 5nm SII\u0026amp;Hb \u003c\/span\u003e\u003cspan\u003ef\u003c\/span\u003e\u003cspan\u003eilter is a dual line-pass filter, which lets the deep red \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eSulfur-II\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e line and the blue \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eHydrogen-Beta\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e line through and is used with one-shot color (OSC) cameras such as DSLR's or astronomical OSC cameras. It is a significant addition to the popular Antlia ALP-T dual band 5nm Ha\u0026amp;OIII filter and enables false-color images and narrow-band nebula images using OSC. When capturing data with this filter, the nebulae are recorded with greater contrast against the background than without it.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe\u003c\/span\u003e\u003cspan\u003e combination of these two dual band filters allows extreme narrow-band images with OSC cameras by capturing the spectral data from 4 channels i.e. Ha\/OIII\/SII\/Hb. The spectrum of these four channels can be separated and recombined into various colour palettes in your post-processing. The resulting images can be used for luminance contrast enhancement of traditional RGB-balanced images or creation of images in various popular false-color palettes such as \u003c\/span\u003e\u003cspan\u003eH-O-Hb, \u003c\/span\u003e\u003cspan\u003eS\u003c\/span\u003e\u003cspan\u003e-\u003c\/span\u003e\u003cspan\u003eH\u003c\/span\u003e\u003cspan\u003e-\u003c\/span\u003e\u003cspan\u003eO\u003c\/span\u003e\u003cspan\u003e,\u003c\/span\u003e\u003cspan\u003e \u003c\/span\u003e\u003cspan\u003eH-S-OHb, H-O-O etc.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eWhy design SII\u0026amp;Hb band\u003c\/span\u003e\u003c\/strong\u003e\u003cstrong\u003e\u003cspan\u003es pass\u003c\/span\u003e\u003c\/strong\u003e\u003cstrong\u003e\u003cspan\u003e \u003c\/span\u003e\u003c\/strong\u003e\u003cstrong\u003e\u003cspan\u003einstead of \u003c\/span\u003e\u003c\/strong\u003e\u003cstrong\u003e\u003cspan\u003eOIII\u0026amp;SII bands?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe filter is dedicated to capture H-beta and SII emission lines. We know that SII is s\u003c\/span\u003e\u003cspan\u003eingly ionized sulfur that emits light in the deep red part of the spectrum, beyond H-alpha, \u003c\/span\u003e\u003cspan\u003ebut the \u003c\/span\u003e\u003cspan\u003econtribution of H-beta to emission lines in nebulae \u003c\/span\u003e\u003cspan\u003eis frequently overlooked, even though it is t\u003c\/span\u003e\u003cspan\u003ehe second most common Hydrogen emission after the H-alpha line. \u003c\/span\u003e\u003cspan\u003eC\u003c\/span\u003e\u003cspan\u003eapturing more OIII will boost the existing signal but does not give more information. However Hb has \u003c\/span\u003e\u003cspan\u003ethe \u003c\/span\u003e\u003cspan\u003epotential to reveal structures not seen using OIII.\u003c\/span\u003e\u003cspan\u003e \u003c\/span\u003e\u003cspan\u003eThe de\u003c\/span\u003e\u003cspan\u003esign\u003c\/span\u003e\u003cspan\u003e is to capture the H-beta emission line in the certain nebulas that contain some blue spectrum, this cannot be captured by \u003c\/span\u003e\u003cspan\u003eH-alpha, SII and OIII filters\u003c\/span\u003e\u003cspan\u003e. \u003c\/span\u003e\u003cspan\u003eGreater and richer details will be captured in many nebulae images to achieve results with a superior signal-to-noise ratio. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eIt is generally accepted that the OIII signal is a relatively weaker contributor to nebulae images. The OIII bandpass sensitivity is an important consideration for any nebulae filter.\u003c\/span\u003e\u003cspan\u003e \u003c\/span\u003e\u003cspan\u003eMost colour cameras (OSC) use a RGGB Bayer pattern. The allocation of twice as many green pixels as compared to either red or blue pixels, enables a much-improved capture of the OIII signal.\u003c\/span\u003e\u003cspan\u003e Furthermore, \u003c\/span\u003e\u003cspan\u003ehigher OIII signal can be achieved by additional exposure using the Antlia ALP-T Ha\u0026amp;O3 filter, then isolating the GB channels, followed by synthesis of an OIII channel to add into your stack.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eIn the situation where you may only want to add SII to your Ha\u0026amp;OIII data, then it may be preferable to buy one SII \u003c\/span\u003e\u003cspan\u003enarrowband\u003c\/span\u003e\u003cspan\u003e filter and \u003c\/span\u003e\u003cspan\u003eachieve a cleaner SII spectral emission. However, our new filter design (SII\u0026amp;Hb) includes the H-beta emission line which provides a distinct improvement in nebulae contrast and improved feature separation in Hb areas.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eAntlia ALP-T Dual Band 5nm Ha\u0026amp;OIII filter\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e: Dual band filter with a very narrow passband of 5nm in OIII and H-alpha to achieve a higher signal-to-noise ratio. The resulting contrast improvement for OSC is impressive.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eAntlia ALP-T Dual Band 5nm SII\u0026amp;Hb filter: \u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003eDual band filter with a very narrow pass band of 5nm H-beta and S-II. This filter is ideal for \u003c\/span\u003e\u003cspan\u003ei\u003c\/span\u003e\u003cspan\u003encreas\u003c\/span\u003e\u003cspan\u003eing\u003c\/span\u003e\u003cspan\u003e contrast of nebulae that \u003c\/span\u003e\u003cspan\u003eemit\u003c\/span\u003e\u003cspan\u003e in the sulfur\u003c\/span\u003e\u003cspan\u003e and \u003c\/span\u003e\u003cspan\u003eH-beta\u003c\/span\u003e\u003cspan\u003e \u003c\/span\u003e\u003cspan\u003erange using OSC\u003c\/span\u003e\u003cspan\u003e.\u003c\/span\u003e\u003cspan\u003e It provides additional feature separation and isolation in Hb areas.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe advanced multi-coatings on Antlia ALP-T dual band filters effectively isolates the red, Ha line, blue-green, OIII line, deep red SII and the blue H-beta lines from emission nebulae, with almost total suppression of optical density (OD)4.5 on unwanted wavelengths from light pollution, moonlight, and airglow. The result is that both\u003c\/span\u003e\u003cspan\u003e the\u003c\/span\u003e\u003cspan\u003e ALP-T dual band 5nm Ha\u0026amp;OIII and SII\u0026amp;Hb filter create\u003c\/span\u003e\u003cspan\u003es\u003c\/span\u003e\u003cspan\u003e a superior signal-to-noise ratio and better contrast in your OSC images.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eThe main features and app\u003c\/span\u003e\u003c\/strong\u003e\u003cstrong\u003e\u003cspan\u003eli\u003c\/span\u003e\u003c\/strong\u003e\u003cstrong\u003e\u003cspan\u003ecation\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003ePasses SII 672.4nm line and H-Beta 486.1nm line\u003c\/span\u003e\u003cspan\u003e;\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eEngineered specifically for use with DSLR, CMOS, and CCD color cameras\u003c\/span\u003e\u003cspan\u003e;\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eUltra \u003c\/span\u003e\u003cspan\u003eFWHM \u003c\/span\u003e\u003cspan\u003e5nm \u003c\/span\u003e\u003cspan\u003ea\u003c\/span\u003e\u003cspan\u003ellows for increasing in exposure time\u003c\/span\u003e\u003cspan\u003e;\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eRecommended to be used with ALP-T Dual Band 5nm Ha\u0026amp;OIII filter to \u003c\/span\u003e\u003cspan\u003ecreate images with better \u003c\/span\u003e\u003cspan\u003esignal\u003c\/span\u003e\u003cspan\u003e to noise and better \u003c\/span\u003e\u003cspan\u003eisolation\u003c\/span\u003e\u003cspan\u003e between the 4 channels\u003c\/span\u003e\u003cspan\u003e;\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eSuppression of optical density (OD)4.5 on unwanted wavelengths improves signal-to-noise\u003c\/span\u003e\u003cspan\u003e;\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eExtremely steep bandpass and blackened edges \u003c\/span\u003e\u003cspan\u003eof unmounted sizes \u003c\/span\u003e\u003cspan\u003eto minimize internal reflections\u003c\/span\u003e\u003cspan\u003e;\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eIdeal flat-top and moderate bandpass reducing spectrum down shifts\u003c\/span\u003e\u003cspan\u003e;\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eIon Gun Assisted Deposition coating technology on the double-sided polished substrate making it the most consistent and accurate light pollution suppression filter\u003c\/span\u003e\u003cspan\u003e;\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eDesigned to suppress artificial lighting from Bortle scale 1 to Bortle scale 8\u003c\/span\u003e\u003cspan\u003e;\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eIt can also be used as a narrowband filter for monochrome cameras to save imaging time\u003c\/span\u003e\u003cspan\u003e;\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eNear IR (NIR) is blocked up to 1100nm\u003c\/span\u003e\u003cspan\u003e.\u003c\/span\u003e\u003c\/p\u003e","brand":"Antlia","offers":[{"title":"2\" Mounted","offer_id":45077820997917,"sku":"ANT-ALP-T-SII-HB-2","price":497.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Antlia-ALP-T-Dualband-5nm-Filter.jpg?v=1685810699"},{"product_id":"antlia-alp-t-dualband-5nm-ha-oiii-highspeed-filter","title":"Antlia ALP-T Dualband 5nm Ha\/OIII Highspeed Filter","description":"\u003c!-- more --\u003e\n\u003cp\u003eALP-T Dual Band 5nm Highspeed Filters are further optimized to work with high-speed imaging systems by shifting slightly the passband and center wavelength. Using these highspeed filters between optics f\/2.2 and f\/3.6 shows much stronger and more contrasted in nebulae imaging compared to the standard version.\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eFor optics f-ratios slower than f\/3.6, the standard ALP-T Dual Band 5nm filter is highly recommended. Meanwhile, if you seek the best possible performance with any optics faster than f\/2.2, the highspeed version is the best choice.\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eBut keep in mind, the blue shift data by the computer simulation indicates narrowband filter shifts its bandwidth to shorter wavelengths with faster optics than f\/2, transmission at the emission wavelength may decrease perhaps 15%-20%. Although the Antlia ALP-T highspeed filter has similar transmission rates reduction in the H-a and OIII when the filter is used on fast optics, based on current standard version users’ data, it is evident that the filter still has the high performance of increase in emission nebula contrast and minimized halo.\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eThe highspeed version price is the same as the standard filters and double benefits for the high-speed optics users. Worth mentioning is that Antlia inspected and measured products piece by piece with one of Agilent Cary’s professional spectrophotometer, resolution\/slit width is up to 0.2nm, which make us provide highly reliable and consistent products to you.\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eThe Antlia ALP-T dual band 5nm series filter is a dual line-pass filter that was designed to be used primarily with one-shot color (OSC) cameras such as DSLR's and astronomical OSC cameras. It can also be used as a narrowband filter for monochrome cameras to save imaging time. The advanced multi-coatings on our ALP-T ultra dual band filter effectively isolate the red Ha and the blue-green OIII lines light from emission nebulae, with almost total suppression of optical density (OD)4.5 on unwanted wavelengths from light pollution, moonlight, and airglow. The result is that our ALP-T dual band 5nm filter creates a superior signal-to-noise ratio and better contrast in your images.\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eThe filter enables the capture of the two main emission nebulae bands at the same time, whilst suppressing unwanted light pollution. It enables you to capture cleaner data and reduces the post-processing efforts to isolate faint details from the background light pollution.\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eApplication and Performance: \u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eDesigned especially for fast astronomy optics, in particular f-ratios f\/2.2 to f\/3.6\u003c\/p\u003e\n\u003cp\u003eEngineered specifically for use with DSLR, CMOS, and CCD color cameras\u003c\/p\u003e\n\u003cp\u003eSuppression of optical density (OD)4.5 on unwanted wavelengths adds signal-to-noise\u003c\/p\u003e\n\u003cp\u003eExtremely steep bandpass edges minimize internal reflections\u003c\/p\u003e\n\u003cp\u003eIdeal flat-top and moderate bandpass reducing spectrum down shifts\u003c\/p\u003e\n\u003cp\u003eIon Gun Assisted Deposition coating technology on the double-sided polished substrate making it the most consistent and accurate light pollution suppression filter\u003c\/p\u003e\n\u003cp\u003eDesigned to suppress artificial lighting from Bortle scale 1 to Bortle scale 8\u003c\/p\u003e\n\u003cp\u003eNear IR (NIR) is blocked up to 1050nm\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eTechnical Specifications:\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003ctable border=\"1\" align=\"LEFT\" width=\"585px\" bordercolor=\"#000000\" _innercreatetable=\"true\" units=\"hasPercent\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd valign=\"top\" width=\"22.6%\" bordercolor=\"#000000\"\u003e\u003cbr\u003e\u003c\/td\u003e\n\u003ctd valign=\"top\" width=\"25.3%\" bordercolor=\"#000000\"\u003e\u003cspan\u003eHydrogen-alpha\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd valign=\"top\" width=\"24.7%\" bordercolor=\"#000000\"\u003e\u003cspan\u003eOxygen III\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd valign=\"top\" width=\"22.6%\" bordercolor=\"#000000\"\u003e\u003cspan\u003eFWHM\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd valign=\"top\" width=\"25.3%\" bordercolor=\"#000000\"\u003e\u003cspan\u003e5nm\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd valign=\"top\" width=\"24.7%\" bordercolor=\"#000000\"\u003e\u003cspan\u003e5nm\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd valign=\"top\" width=\"22.6%\" bordercolor=\"#000000\"\u003e\u003cspan\u003eCWL (Central Wavelength)\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd valign=\"top\" width=\"25.3%\" bordercolor=\"#000000\"\u003e\u003cspan\u003e657.8nm\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd valign=\"top\" width=\"24.7%\" bordercolor=\"#000000\"\u003e\u003cspan\u003e502.2nm\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd valign=\"top\" width=\"22.6%\" bordercolor=\"#000000\"\u003e\u003cspan\u003ePeak Transmission\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd valign=\"top\" width=\"25.3%\" bordercolor=\"#000000\"\u003e\u003cspan\u003e88%\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd valign=\"top\" width=\"24.7%\" bordercolor=\"#000000\"\u003e\u003cspan\u003e82%\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd valign=\"top\" width=\"22.6%\" bordercolor=\"#000000\"\u003e\u003cspan\u003eBlocking\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd colspan=\"2\" rowspan=\"1\" valign=\"top\" bordercolor=\"#000000\"\u003e\n\u003cspan\u003e≥\u003c\/span\u003e\u003cspan\u003eOD4.5 @ 300-1050nm\u003c\/span\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd valign=\"top\" width=\"22.6%\" bordercolor=\"#000000\"\u003e\u003cspan\u003eFilter Thickness\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd colspan=\"2\" valign=\"top\" bordercolor=\"#000000\"\u003e\u003cspan\u003e2mm+\/-0.05mm\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eFilter Ring: \u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e2'' (M48*0.75)\u003c\/p\u003e\n\u003cp\u003eUltra-thin filter cell to minimize vignetting by maximize possible clear aperture\u003c\/p\u003e\n\u003cp\u003eBlack Anodized Finish\u003c\/p\u003e\n\u003cp\u003eLaser Engraving No Fading\u003c\/p\u003e","brand":"Antlia","offers":[{"title":"2\" Mounted","offer_id":45077823815965,"sku":"ANT-ALP-T-HS-2","price":540.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Antlia-ALP-T-Dualband-5nm-Filter_fd3f123c-ea97-42a5-8c88-c5ee1d114943.jpg?v=1685810834"},{"product_id":"antlia-alp-t-dualband-5nm-ha-oiii-filter","title":"Antlia ALP-T Dualband 5nm Ha\/OIII Filter","description":"\u003c!-- more --\u003e\n\u003cp\u003e\u003cspan\u003eThe \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eAntlia ALP-T \u003c\/span\u003e\u003c\/strong\u003e\u003cstrong\u003e\u003cspan\u003edual band\u003c\/span\u003e\u003c\/strong\u003e\u003cstrong\u003e\u003cspan\u003e 5nm\u003c\/span\u003e\u003c\/strong\u003e\u003cstrong\u003e\u003cspan\u003e \u003c\/span\u003e\u003c\/strong\u003e\u003cstrong\u003e\u003cspan\u003eHa\u0026amp;OIII\u003c\/span\u003e\u003c\/strong\u003e\u003cstrong\u003e\u003cspan\u003e filter\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e is a dual line-pass filter which was designed to be used primarily with one-shot color (OSC) cameras such as DSLR's \u003c\/span\u003e\u003cspan\u003eand\u003c\/span\u003e\u003cspan\u003e astronomical OSC cameras. It can also be used as a narrowband filter for monochrome cameras to save imaging time. The advanced multi-coatings on \u003c\/span\u003e\u003cspan\u003eAntlia\u003c\/span\u003e\u003cspan\u003e ALP-T ultra dual band filter effectively isolates the red \u003c\/span\u003e\u003cspan\u003eHa\u003c\/span\u003e\u003cspan\u003e and the blue-green OIII lines light from emission nebulae, with almost total suppression of \u003c\/span\u003e\u003cspan\u003eo\u003c\/span\u003e\u003cspan\u003eptical \u003c\/span\u003e\u003cspan\u003ed\u003c\/span\u003e\u003cspan\u003eensity \u003c\/span\u003e\u003cspan\u003e(\u003c\/span\u003e\u003cspan\u003eOD\u003c\/span\u003e\u003cspan\u003e)\u003c\/span\u003e\u003cspan\u003e4.5 on unwanted wavelengths from light pollution, moonlight, and airglow. The result is that our ALP-T dual\u003c\/span\u003e\u003cspan\u003e \u003c\/span\u003e\u003cspan\u003eband 5nm filter creates a superior signal-to-noise ratio and better contrast in your images.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe filter enables the capture of the two main emission nebulae bands at the same time, whilst suppressing unwanted light pollution. It enables you to capture cleaner data and reduces the post processing efforts to isolate faint details from the background light pollution.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eApplication and Performance:\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eEngineered specifically for use with DSLR, CMOS, and CCD color cameras\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eSuppression of \u003c\/span\u003e\u003cspan\u003eoptical density (OD)\u003c\/span\u003e\u003cspan\u003e4.5 on unwanted wavelengths adds signal-to-noise\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eExtremely steep \u003c\/span\u003e\u003cspan\u003ebandpass\u003c\/span\u003e\u003cspan\u003e edges minimize internal reflections\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eIdeal flat-top and moderate bandpass reducing spectrum down shifts\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eIon Gun Assisted Deposition coating technology on the double-sided polished substrate\u003c\/span\u003e\u003cspan\u003e \u003c\/span\u003e\u003cspan\u003emaking it the most\u003c\/span\u003e\u003cspan\u003e \u003c\/span\u003e\u003cspan\u003econsistent and accurate light pollution suppression filter \u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eDesigned to suppress artificial lighting from \u003c\/span\u003e\u003cspan\u003eBortle scale\u003c\/span\u003e\u003cspan\u003e 1 to \u003c\/span\u003e\u003cspan\u003eBortle scale\u003c\/span\u003e\u003cspan\u003e 8\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eNear IR (NIR) is blocked up to 1100nm\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eTechnical Specifications:\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable cellspacing=\"0\" border=\"1\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd valign=\"top\" width=\"232\"\u003e\u003cbr\u003e\u003c\/td\u003e\n\u003ctd valign=\"top\" width=\"217\"\u003e\n\u003cp\u003e\u003cspan\u003eHydrogen-alpha\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd valign=\"top\" width=\"210\"\u003e\n\u003cp\u003e\u003cspan\u003eOxygen III\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd valign=\"top\" width=\"232\"\u003e\n\u003cp\u003e\u003cspan\u003eFWHM\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd valign=\"top\" width=\"217\"\u003e\n\u003cp\u003e\u003cspan\u003e5nm\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd valign=\"top\" width=\"210\"\u003e\n\u003cp\u003e\u003cspan\u003e5nm\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd valign=\"top\" width=\"232\"\u003e\n\u003cp\u003e\u003cspan\u003eCWL (Central Wavelength)\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd valign=\"top\" width=\"217\"\u003e\n\u003cp\u003e\u003cspan\u003e656.3nm\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd valign=\"top\" width=\"210\"\u003e\n\u003cp\u003e\u003cspan\u003e500.7nm\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd valign=\"top\" width=\"232\"\u003e\n\u003cp\u003e\u003cspan\u003ePeak Transmission\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd valign=\"top\" width=\"217\"\u003e\n\u003cp\u003e\u003cspan\u003e9\u003c\/span\u003e\u003cspan\u003e2\u003c\/span\u003e\u003cspan\u003e%\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd valign=\"top\" width=\"210\"\u003e\n\u003cp\u003e\u003cspan\u003e8\u003c\/span\u003e\u003cspan\u003e8\u003c\/span\u003e\u003cspan\u003e%\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd valign=\"top\" width=\"232\"\u003e\n\u003cp\u003e\u003cspan\u003eBlocking\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd colspan=\"2\" valign=\"top\" width=\"426\"\u003e\n\u003cp\u003e\u003cspan\u003e≥\u003c\/span\u003e\u003cspan\u003eOD4.5 @ 300-1100nm\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd valign=\"top\" width=\"232\"\u003e\n\u003cp\u003e\u003cspan\u003eFilter Thickness\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003ctd colspan=\"2\" valign=\"top\" width=\"426\"\u003e\n\u003cp\u003e\u003cspan\u003e2mm+\/-0.05mm\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e","brand":"Antlia","offers":[{"title":"2\" Mounted","offer_id":45077868478749,"sku":"ANT-ALP-T-2","price":540.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Antlia-ALP-T-Dualband-5nm-Filter_422c581a-decd-4477-8e9a-260245f0f792.jpg?v=1685811364"},{"product_id":"antlia-alp-t-filter-set","title":"Antlia ALP-T Dualband 5nm Ha\/OIII and SII\/Hb Filter Set - 2\"","description":"","brand":"Antlia","offers":[{"title":"Default Title","offer_id":45077902983453,"sku":"ANT-ALP-T-SET","price":980.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Antlia-ALP-T-Dualband-5nm-Filter-Set.jpg?v=1685811953"},{"product_id":"askar-6nm-color-magic-super-sii-oiii-d2-filter-2","title":"Askar 6nm Colour Magic Super SII\/OIII D2 Filter - 2\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDual-band filter passing OIII (6.5nm) and SII (8.5nm) wavelengths\u003c\/li\u003e\n\u003cli\u003ePeak transmittance of 85% for maximum signal capture\u003c\/li\u003e\n\u003cli\u003eDesigned for color cameras to complete the \"Hubble Palette\" (SHO)\u003c\/li\u003e\n\u003cli\u003eStandard 2\" mounted format\u003c\/li\u003e\n\u003cli\u003e1.85mm thickness for near-parfocal performance with other filters\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eAskar 6nm Colour Magic Super SII\/OIII D2 Filter - 2\"\u003c\/h2\u003e\n\u003cp\u003eThe Askar 6nm Colour Magic Super D2 Filter isolates the Sulfur-II and Oxygen-III emission lines, capturing the two signals often missing from standard color camera workflows. With a narrow 8.5nm bandpass for SII (672nm) and a 6.5nm bandpass for OIII (500.7nm), this filter achieves a peak transmittance of 85% to preserve faint nebula detail. Its ≥OD5 blocking across the 200-1100nm spectrum ensures high-contrast images by eliminating light pollution and stellar bloat, making it the essential second filter for creating full Hubble Palette images with a one-shot-color camera.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e6.5nm\/8.5nm Bandpasses with 85% Peak Transmittance\u003c\/h3\u003e\n\u003cp\u003eThe filter's dual-passband design is precisely engineered to isolate key emission lines. The 6.5nm FWHM centered on the 500.7nm OIII line and the slightly wider 8.5nm FWHM on the 672nm SII line provide an excellent balance between signal strength and contrast. This design allows the filter to deliver over 85% of the light from these specific wavelengths while aggressively rejecting city glow and other unwanted background signal.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eUnlocking Full SHO Imaging for Your Color Camera\u003c\/h3\u003e\n\u003cp\u003eFor imagers using color cameras, duo-narrowband filters that pass H-alpha and OIII are common, but they leave out the critical Sulfur-II data needed for the classic Hubble Palette (SHO). The Askar Super D2 filter is the missing link, designed specifically to be used in conjunction with an Hα\/OIII filter. By capturing SII and additional OIII data in a separate session, you can gather all three channels required to assemble a full SHO image without the complexity of a monochrome camera and filter wheel.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOptical Precision: OD5 Blocking and 30\" Parallelism\u003c\/h3\u003e\n\u003cp\u003eHigh-end imaging requires more than just narrow bandpasses. The Super D2 filter is built on a substrate with a parallelism of 30 arcseconds, preventing image degradation or focus shift when inserted into the optical train. With an optical density (OD) of 5 or greater, it blocks unwanted wavelengths from 200nm to 1100nm, effectively eliminating artifacts from UV, IR, and broadband light pollution for cleaner, higher-contrast results.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eAskar D2 Workflow: Adding the SII Channel to Your Data\u003c\/h3\u003e\n\u003cp\u003eIntegrating this filter into your imaging routine is straightforward. First, capture your primary data using a standard Hα\/OIII duo-band filter. Then, swap to the Askar Super D2 filter to capture the SII and OIII channels. In post-processing, you can combine the Hα from your first session with the SII from your second, and use the OIII data from whichever set is cleaner, giving you a complete H-S-O dataset. This two-filter approach is a powerful and cost-effective method for bringing monochrome-style palette flexibility to your color camera, and performs well even on fast optical systems.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I use the Askar 6nm D2 filter with my existing Hα\/OIII duo-band filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYou use them in two separate imaging sessions. First, capture data with your Hα\/OIII filter. Then, without changing your framing, swap to the Askar D2 filter and capture more data for a similar total integration time. In processing, you will extract the Hα channel from the first session's data and the SII channel from the second session's data. You can then use the OIII data from either or both sessions to create a final SHO color image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the advantage of the Askar D2 filter's 6.5nm OIII and 8.5nm SII bandpasses?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e6.5nm OIII bandpass\u003c\/strong\u003e is very restrictive, which dramatically increases contrast and rejects moonlight or light pollution around the critical Oxygen-III lines. The slightly wider \u003cstrong\u003e8.5nm SII bandpass\u003c\/strong\u003e allows for a stronger signal from the typically fainter Sulfur-II line, helping to balance the data capture between the two wavelengths for better color results.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Askar 6nm D2 filter for visual observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this filter is designed exclusively for astrophotography. Its bandpasses are extremely narrow (6.5nm and 8.5nm), and the human eye cannot gather enough light through such a restrictive filter to see anything. It requires long exposures with a camera to build up an image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Askar 6nm D2 filter work well with my f\/4 RASA or Hyperstar system?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. While not specifically designated as a \"high-speed\" filter, Askar has confirmed it performs well with fast optical systems. The filter's design minimizes the band-shifting effects that can occur with very fast focal ratios, ensuring you can still capture strong OIII and SII signals without significant transmission loss.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Askar D2 filter help me image targets like the Eagle Nebula (M16) in the Hubble Palette?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Eagle Nebula's \"Pillars of Creation\" are rich in all three narrowband gases. A standard duo-band filter captures the Hα and OIII, but misses the SII that traces the densest dust and ionization fronts. By using the Askar D2 filter, you capture that missing SII data, allowing you to assign Hα, SII, and OIII to the Red, Green, and Blue channels respectively in post-processing to create a vibrant, detailed SHO Hubble Palette image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the 1.85mm thickness of the Askar D2 filter make it parfocal with other brands?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e1.85 ± 0.05mm\u003c\/strong\u003e thickness is very close to the standard used by many filter manufacturers. This means it should be nearly parfocal, requiring minimal to no refocusing when swapping between filters of a similar thickness. This is a significant advantage when conducting the two-session imaging workflow required for SHO with a color camera.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eDual-Band Narrowband\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSize\u003c\/td\u003e\n\u003ctd\u003e2\" Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFWHM (OIII)\u003c\/td\u003e\n\u003ctd\u003e6.5nm ± 0.5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFWHM (SII)\u003c\/td\u003e\n\u003ctd\u003e8.5nm ± 0.5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCenter Wavelength (CWL)\u003c\/td\u003e\n\u003ctd\u003e500.7nm (OIII) \u0026amp; 672nm (SII)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePeak Transmittance\u003c\/td\u003e\n\u003ctd\u003e≥85%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Range\u003c\/td\u003e\n\u003ctd\u003e≥OD5 @ 200-1100nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Thickness\u003c\/td\u003e\n\u003ctd\u003e1.85mm ± 0.05mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Finish\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/www.sharpstar-optics.com\/download_list_1\/7.html\" target=\"_blank\"\u003e\u003csvg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 640 512\" class=\"DAV-img-box\"\u003e\u003cpath fill=\"#0047a7\" d=\"M128 32C92.7 32 64 60.7 64 96l0 256 64 0 0-256 384 0 0 256 64 0 0-256c0-35.3-28.7-64-64-64L128 32zM19.2 384C8.6 384 0 392.6 0 403.2C0 445.6 34.4 480 76.8 480l486.4 0c42.4 0 76.8-34.4 76.8-76.8c0-10.6-8.6-19.2-19.2-19.2L19.2 384z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e \n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eDownload Software \u0026amp; Drivers\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/askar-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eAskar 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Askar","offers":[{"title":"Default Title","offer_id":47078711591197,"sku":"ASK-ASK2DNSOD2","price":447.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Askar-Color-Magic-D2-Filter.jpg?v=1699985639"},{"product_id":"askar-colour-magic-sii-oiii-c2-filter-2","title":"Askar Colour Magic SII\/OIII C2 Filter - 2\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDual-band filter passing SⅡ (672nm) and OIII (500.7nm) emission lines\u003c\/li\u003e\n\u003cli\u003eDesigned for one-shot-color cameras to capture data often missed by Hα\/OIII filters\u003c\/li\u003e\n\u003cli\u003e15nm±3nm bandpass for the Sulfur-II (SⅡ) line\u003c\/li\u003e\n\u003cli\u003e35nm±5nm bandpass for the Oxygen-III (OIII) line\u003c\/li\u003e\n\u003cli\u003e90% peak transmittance for high signal-to-noise ratio\u003c\/li\u003e\n\u003cli\u003eOD3 blocking from 200-1000nm suppresses light pollution and unwanted signal\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eAskar Colour Magic SII\/OIII C2 Filter - 2\"\u003c\/h2\u003e\n\u003cp\u003eThe Askar Colour Magic C2 2\" filter isolates the Sulfur-II and Oxygen-III emission lines, capturing the \"missing\" SⅡ channel for one-shot-color camera users. With a tight 15nm±3nm bandpass at 672nm for SⅡ and a wider 35nm±5nm bandpass at 500.7nm for OIII, it achieves over 90% peak transmittance on these critical wavelengths. This design allows you to gather data for full SHO (Hubble Palette) style images without switching to a monochrome camera and filter wheel.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe \"Missing Channel\" Solution: Adding SⅡ Data to Color Images\u003c\/h3\u003e\n\u003cp\u003eMost duo-band filters for color cameras focus on Hydrogen-alpha and Oxygen-III, leaving out the crucial Sulfur-II signal that reveals unique structures in many emission nebulae. The Askar Colour Magic C2 filter is engineered specifically to fill this gap. By capturing SⅡ and OIII simultaneously, it provides the data needed to complement your existing Hα\/OIII images, unlocking the ability to create full tricolor narrowband composites with a single color camera.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eAsymmetrical Design: 15nm SⅡ and 35nm OIII Bandpasses\u003c\/h3\u003e\n\u003cp\u003eThe filter features two different bandpasses to optimize signal capture for each emission line. The tighter 15nm±3nm FWHM for the SⅡ line provides excellent contrast and aggressively rejects light pollution for this often-fainter signal. The broader 35nm±5nm FWHM for OIII allows for greater light collection on this typically stronger signal, which is beneficial for reducing exposure times while still offering a significant improvement over broadband filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e90% Peak Transmittance for Maximum Contrast\u003c\/h3\u003e\n\u003cp\u003eAchieving over 90% peak transmittance at the 672nm and 500.7nm center wavelengths ensures that the maximum amount of valuable nebula light reaches your sensor. Combined with strong out-of-band blocking rated at OD3 from 200-1000nm, the C2 filter darkens the sky background significantly, even under moderately light-polluted skies. This high transmission and strong blocking work together to dramatically increase image contrast, making faint details in targets like the Trifid Nebula (M20) or the Eagle Nebula (M16) stand out clearly.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy use the Askar C2 SⅡ\/OIII filter instead of a standard Hα\/OIII filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Askar C2 is not a replacement for an Hα\/OIII filter; it's a \u003cstrong\u003ecomplement\u003c\/strong\u003e. Standard duo-band filters capture Hα and OIII. The C2 filter captures SⅡ and OIII, providing the third channel of data necessary for creating Hubble Palette (SHO) images with a color camera. You use both filters to acquire all three datasets.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I combine data from the Askar C2 filter with my other images?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAfter capturing separate images with your Hα\/OIII filter and the Askar C2 SⅡ\/OIII filter, you would use image processing software like PixInsight or Photoshop. You can split the channels from each image to isolate the Hα, SⅡ, and OIII data, and then combine them into a single color image by assigning each signal to the Red, Green, and Blue channels as desired.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 35nm bandpass on the OIII channel of the Askar C2 filter wide enough for my light-polluted skies?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA 35nm bandpass provides a good balance between light pollution suppression and signal strength. While not as restrictive as a 3nm or 7nm filter, it is significantly better than a broadband filter and is effective in most suburban environments. The key benefit is shorter exposure times compared to ultra-narrowband filters, which can be an advantage for many imagers.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat types of celestial objects benefit most from the Askar C2 SⅡ\/OIII filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eEmission nebulae with distinct regions of Sulfur-II emission are ideal targets. Objects like the \u003cstrong\u003eEagle Nebula (M16)\u003c\/strong\u003e, the \u003cstrong\u003eTrifid Nebula (M20)\u003c\/strong\u003e, and the \u003cstrong\u003eRosette Nebula (NGC 2237)\u003c\/strong\u003e show dramatic structural differences when SⅡ data is included, allowing for the creation of vibrant and detailed Hubble Palette images.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Askar C2 SⅡ\/OIII filter with a monochrome camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile technically possible, it's not the intended use. With a monochrome camera, the sensor would capture both SⅡ and OIII light simultaneously, and you would not be able to separate them. For monochrome imaging, it is always better to use individual SⅡ and OIII single-bandpass filters to capture clean, isolated data for each channel.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy are the bandpasses different for SⅡ (15nm) and OIII (35nm) on the Askar C2 filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis is a deliberate design choice to optimize performance. The \u003cstrong\u003eSⅡ signal is often weaker\u003c\/strong\u003e, so a tighter 15nm bandpass is used to increase contrast and reject more background light. The \u003cstrong\u003eOIII signal is typically stronger\u003c\/strong\u003e, so a wider 35nm bandpass allows more of this signal to be collected, reducing exposure times without sacrificing too much contrast.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eDual-Band Narrowband\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSize\u003c\/td\u003e\n\u003ctd\u003e2\" Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCenter Wavelength (CWL)\u003c\/td\u003e\n\u003ctd\u003e500.7nm (OIII) \u0026amp; 672nm (SⅡ)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFull Width Half-Max (FWHM)\u003c\/td\u003e\n\u003ctd\u003eOIII: 35nm ±5nm \/ SⅡ: 15nm ±3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePeak Transmittance\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Range\u003c\/td\u003e\n\u003ctd\u003eOD3 (0.1%) @ 200-1000nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eGlass Thickness\u003c\/td\u003e\n\u003ctd\u003e2mm ± 0.05mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Finish\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eAskar Colour Magic C2 SII\/OIII Filter - 2\"\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eProtective Case\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/www.sharpstar-optics.com\/download_list_1\/7.html\" target=\"_blank\"\u003e\u003csvg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 640 512\" class=\"DAV-img-box\"\u003e\u003cpath fill=\"#0047a7\" d=\"M128 32C92.7 32 64 60.7 64 96l0 256 64 0 0-256 384 0 0 256 64 0 0-256c0-35.3-28.7-64-64-64L128 32zM19.2 384C8.6 384 0 392.6 0 403.2C0 445.6 34.4 480 76.8 480l486.4 0c42.4 0 76.8-34.4 76.8-76.8c0-10.6-8.6-19.2-19.2-19.2L19.2 384z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e \n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eDownload Drivers\/Software\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/askar-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eAskar 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Askar","offers":[{"title":"Default Title","offer_id":47429342691613,"sku":"ASK-ASKAR2DBC2","price":167.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/image.png?v=1705009186"},{"product_id":"askar-colour-magic-sii-oiii-c1-filter-2","title":"Askar Colour Magic Ha\/OIII C1 Filter - 2\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDual-bandpass filter for H-alpha (656.6nm) and Oxygen-III (500.7nm)\u003c\/li\u003e\n\u003cli\u003eAsymmetrical bandwidths: 15nm for H-alpha, 35nm for OIII\u003c\/li\u003e\n\u003cli\u003eGreater than 90% peak transmittance at primary emission lines\u003c\/li\u003e\n\u003cli\u003eOD3 (99.9%) blocking of light pollution from 200-1000nm\u003c\/li\u003e\n\u003cli\u003eStandard 2\" mounted format with 2mm thick substrate\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eAskar Colour Magic Ha\/OIII C1 Filter - 2\"\u003c\/h2\u003e\n\u003cp\u003eThe Askar Colour Magic Ha\/OIII C1 filter isolates the two most important emission lines for nebula imaging, Hydrogen-alpha at 656.6nm and Oxygen-III at 500.7nm, with over 90% peak transmittance. Its design uses asymmetrical bandwidths—a tight 15nm±3nm for H-alpha and a wider 35nm±5nm for OIII—to capture strong signal from both wavelengths with a one-shot-color camera. By implementing OD3 blocking across the 200-1000nm spectrum, the C1 filter darkens the sky background for maximum image contrast, even from light-polluted locations.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eIsolate Ha \u0026amp; OIII with 90% Peak Transmittance\u003c\/h3\u003e\n\u003cp\u003eThe Colour Magic C1 is engineered to pass only the light from ionized hydrogen (Hα at 656.6nm) and doubly ionized oxygen (OIII at 500.7nm). With a peak transmittance of over 90% at these critical wavelengths, your camera sensor collects maximum signal from emission nebulae like the North American Nebula (NGC 7000) or the Veil Nebula complex, while rejecting unwanted city lights and natural skyglow.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eAsymmetrical Bandwidths: 15nm Ha and 35nm OIII for Color Balance\u003c\/h3\u003e\n\u003cp\u003eUnlike filters with identical bandwidths, the Askar C1 uses a purpose-built asymmetrical design. The H-alpha line is restricted to a tight 15nm±3nm bandpass for high-contrast detail in hydrogen-rich regions. The OIII bandpass is set to a much wider 35nm±5nm, allowing more signal to reach the sensor. This approach helps balance the often-weaker OIII signal against the typically dominant H-alpha, producing a richer, more natural color result directly from your one-shot-color (OSC) camera with less processing effort.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOD3 Blocking for High-Contrast Images in Light Pollution\u003c\/h3\u003e\n\u003cp\u003eEffective imaging requires not just passing the desired signal, but aggressively blocking everything else. The C1 filter provides OD3 blocking, equivalent to rejecting 99.9% of incoming light, across a vast 200-1000nm range outside of its passbands. This comprehensive blocking eliminates interference from common sources of light pollution like sodium and mercury-vapor streetlights, as well as moonlight and general skyglow, producing a dark, neutral background and making nebula structures stand out with dramatic contrast.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eAskar C1 vs. Symmetrical Filters: A Design for OSC Imaging\u003c\/h3\u003e\n\u003cp\u003eMany popular dual-band filters use very narrow, symmetrical bandpasses (e.g., 7nm for both Ha and OIII). While those filters offer slightly higher contrast and produce smaller stars, the Askar C1's asymmetrical design presents a distinct advantage for OSC imagers.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompetitor Advantage:\u003c\/strong\u003e Symmetrical ultra-narrowband filters provide the highest possible contrast on individual emission lines and are ideal for monochrome imaging or advanced processing techniques where data from each line is handled separately.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAskar C1 Advantage:\u003c\/strong\u003e By widening the OIII band to 35nm, the C1 captures more OIII signal relative to Ha in the same exposure time. This helps prevent the final color image from being overwhelmingly red and yields a more balanced initial result, reducing the need for complex color calibration in post-processing.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy does the Askar Colour Magic C1 filter have different bandwidths for H-alpha and OIII?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe asymmetrical design is a deliberate choice to improve color balance for one-shot-color (OSC) cameras. The \u003cstrong\u003e15nm H-alpha band\u003c\/strong\u003e provides high contrast, while the wider \u003cstrong\u003e35nm OIII band\u003c\/strong\u003e allows more of the typically weaker OIII signal to be captured. This helps prevent images from being overwhelmingly red and produces a more natural color result with less processing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Askar C1 filter perform in Bortle 8\/9 skies?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Askar C1 filter is highly effective in heavily light-polluted skies. Its \u003cstrong\u003eOD3 blocking\u003c\/strong\u003e across the 200-1000nm spectrum aggressively rejects common sources of urban light pollution. By only passing the specific 656.6nm and 500.7nm wavelengths of nebulae, it dramatically darkens the sky background, allowing you to capture high-contrast images of emission nebulae even from the city.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Askar C1 filter for imaging the Andromeda Galaxy (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this is not the right filter for broadband targets like galaxies or star clusters. The Askar C1 is a dual-bandpass filter that blocks almost all light except for specific emission lines. Since galaxies like M31 shine primarily in continuous-spectrum starlight, this filter would block the vast majority of their light, resulting in a very faint and incomplete image. A broadband light pollution filter is a better choice for galaxies from the city.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of color balance can I expect from the Askar C1 filter on the Orion Nebula (M42)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eOn a target like the Orion Nebula (M42), which is rich in both hydrogen and oxygen, the Askar C1 filter is designed to deliver a well-balanced color image with an OSC camera. The tight 15nm band will capture fine details in the red H-alpha regions, while the broad 35nm OIII band will ensure the blue-green structures in the Trapezium core are bright and prominent, avoiding an overly red final image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Askar C1 filter suitable for monochrome cameras?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile it can be used, it's not ideal. A monochrome camera cannot separate the H-alpha and OIII signals captured simultaneously by the Askar C1 filter. For monochrome imaging, it is far more effective to use separate, dedicated H-alpha and OIII single-bandpass filters to capture data for each channel individually, allowing for full processing control and palette creation (like the Hubble Palette).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does the OD3 @ 200-1000nm rating on the Askar C1 filter mean?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eOD3\u003c\/strong\u003e stands for Optical Density 3, which means the filter blocks 99.9% of light outside its designated passbands. The \u003cstrong\u003e@ 200-1000nm\u003c\/strong\u003e specification indicates this high level of blocking is applied across the entire spectrum from deep ultraviolet to near-infrared. This ensures a very dark, high-contrast background free from light pollution and other unwanted signals.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eDual-Bandpass Narrowband\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWavelength 1 (CWL)\u003c\/td\u003e\n\u003ctd\u003e656.6nm (H-alpha)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWavelength 2 (CWL)\u003c\/td\u003e\n\u003ctd\u003e500.7nm (OIII)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandwidth (FWHM) H-alpha\u003c\/td\u003e\n\u003ctd\u003e15nm ± 3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandwidth (FWHM) OIII\u003c\/td\u003e\n\u003ctd\u003e35nm ± 5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePeak Transmittance\u003c\/td\u003e\n\u003ctd\u003e\u0026gt; 90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Efficiency\u003c\/td\u003e\n\u003ctd\u003eOD3 (99.9%)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Range\u003c\/td\u003e\n\u003ctd\u003e200nm - 1000nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Thickness\u003c\/td\u003e\n\u003ctd\u003e2mm ± 0.05mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Finish\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eAskar Colour Magic Ha\/OIII C1 Filter - 2\"\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eProtective Case\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/www.sharpstar-optics.com\/download_list_1\/7.html\" target=\"_blank\"\u003e\u003csvg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 640 512\" class=\"DAV-img-box\"\u003e\u003cpath fill=\"#0047a7\" d=\"M128 32C92.7 32 64 60.7 64 96l0 256 64 0 0-256 384 0 0 256 64 0 0-256c0-35.3-28.7-64-64-64L128 32zM19.2 384C8.6 384 0 392.6 0 403.2C0 445.6 34.4 480 76.8 480l486.4 0c42.4 0 76.8-34.4 76.8-76.8c0-10.6-8.6-19.2-19.2-19.2L19.2 384z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eDownload Software \u0026amp; Drivers\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/askar-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eAskar 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Askar","offers":[{"title":"Default Title","offer_id":47429347672349,"sku":"ASK-ASKAR2DBC1","price":167.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/image_8378cc30-ba51-4d4c-bfe1-c9fbd4710ebc.png?v=1705009394"},{"product_id":"askar-color-magic-ha-oiii-sii-oiii-c1-c2-filter-package","title":"Askar Colour Magic Ha\/OIII \u0026 SII\/OIII (C1+C2) Filter Package","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eComplete 2-Filter Narrowband Solution for Color Cameras\u003c\/li\u003e\n\u003cli\u003eCaptures H-alpha, Oxygen-III, and Sulfur-II Wavelengths\u003c\/li\u003e\n\u003cli\u003eFilter 1 (C1): Hα + OIII Duo-Band\u003c\/li\u003e\n\u003cli\u003eFilter 2 (C2): SII + OIII Duo-Band\u003c\/li\u003e\n\u003cli\u003eEnables Hubble Palette (SHO) Imaging with One-Shot-Color Cameras\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eAskar Colour Magic Ha\/OIII \u0026amp; SII\/OIII (C1+C2) Filter Package\u003c\/h2\u003e\n\u003cp\u003eThe Askar Colour Magic C1+C2 Filter Package is a unique 2-filter system that enables imagers using one-shot-color cameras to capture all three key emission nebula wavelengths—H-alpha, Oxygen-III, and Sulfur-II. This package combines the C1 (Hα+OIII) and C2 (SII+OIII) duo-band filters, providing a direct and efficient path to creating full Hubble palette-style images, even from heavily light-polluted locations.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eA 2-Filter Solution for Color Camera Narrowband Imaging\u003c\/h3\u003e\n\u003cp\u003eThis filter set fundamentally simplifies the process of tri-band narrowband imaging. Instead of requiring a monochrome camera, a filter wheel, and three separate filters (Ha, SII, OIII), the Colour Magic package allows you to achieve a similar result with your existing color camera and just two filters, drastically reducing complexity and cost.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe C1 (Hα+OIII) Filter: Your Primary Nebula Workhorse\u003c\/h3\u003e\n\u003cp\u003eThe first filter in the set, the C1, is a duo-band filter that isolates the two most prominent wavelengths in most emission and planetary nebulae: Hydrogen-alpha and Oxygen-III. For many targets, this filter alone will produce dramatic, high-contrast images by rejecting broadband light pollution from city skies, revealing faint nebulosity that would otherwise be lost.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe C2 (SII+OIII) Filter: Adding Critical Sulfur-II Data\u003c\/h3\u003e\n\u003cp\u003eThe C2 filter is the key to creating full SHO images. It captures the Sulfur-II line, which provides the rich reds and oranges in the Hubble palette, while also capturing more Oxygen-III signal. By capturing OIII data with both filters, you increase the total signal-to-noise ratio on this often-faint wavelength and create a common data layer that simplifies image registration and processing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eColour Magic vs. Mono Imaging: A Streamlined Path to SHO\u003c\/h3\u003e\n\u003cp\u003eA traditional monochrome setup offers maximum control over data acquisition. You can use ultra-narrow filters and precisely control exposure time for each channel, which remains the standard for advanced scientific imaging.\u003c\/p\u003e\n\u003cp\u003eThe Askar Colour Magic system's advantage is workflow efficiency. It makes SHO imaging accessible to anyone with a color astronomy camera, eliminating the need for a filter wheel and the complexities of managing three separate data sets. While data from a duo-band filter is not as pure as from a dedicated mono filter, this package provides an innovative and highly effective way to produce stunning, colorful nebula portraits with far less equipment and acquisition time.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I use the Askar Colour Magic filters to create an SHO image?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYou capture two sets of exposures, one with the \u003cstrong\u003eC1 (Hα+OIII) filter\u003c\/strong\u003e and another with the \u003cstrong\u003eC2 (SII+OIII) filter\u003c\/strong\u003e. In post-processing, you will split the color channels from both data sets. The Red channel from the C1 data becomes your H-alpha, the Red channel from the C2 data becomes your Sulfur-II, and the combined Green\/Blue channels from both sets become your Oxygen-III. These three new monochrome images can then be assigned to the R, G, and B channels to create a Hubble palette image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy does the Askar C2 filter include OIII data along with SII?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eCapturing Oxygen-III data with both filters serves two purposes. First, it increases the total integration time and signal-to-noise ratio on the OIII signal, which is often the weakest of the three. Second, it provides a common structural element (the OIII nebulosity) in both of your master images, which makes aligning and registering the Hα and SII data much easier during processing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use just the Askar C1 (Hα+OIII) filter by itself?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. The C1 filter is an excellent standalone duo-band filter for imaging most emission nebulae like the Orion Nebula (M42) or Lagoon Nebula (M8). It will produce high-contrast color images with natural-looking red and blue-green hues directly from your color camera.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Askar Colour Magic filters work with my 8\" f\/10 SCT on the Orion Nebula (M42)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this filter set is well-suited for an f\/10 SCT. For the Orion Nebula (M42), you could use just the C1 (Hα+OIII) filter to capture its extensive hydrogen and oxygen structures with excellent contrast. Since M42 has very little Sulfur-II signal, using the C2 filter is not typically necessary for this specific target.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does this Askar filter set perform under my Bortle 7 city skies on the Pelican Nebula (IC 5070)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis is an ideal scenario for the Colour Magic filters. From Bortle 7 skies, these filters will aggressively reject broadband light pollution, allowing your color camera to capture clean narrowband data. The Pelican Nebula (IC 5070) is rich in all three wavelengths (Ha, OIII, and SII), making it a perfect target to use both the C1 and C2 filters to create a detailed SHO Hubble palette image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo these Askar filters replace the need for a monochrome camera for narrowband?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFor many amateur astrophotographers, yes. They provide a much simpler and more affordable way to get into tri-band narrowband imaging without investing in a full monochrome setup. While a mono camera offers more control and can use narrower bandpass filters for the absolute highest contrast, this Askar set closes the gap significantly and makes SHO imaging accessible to a much wider audience.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/www.sharpstar-optics.com\/download_list_1\/7.html\" target=\"_blank\"\u003e\u003csvg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 640 512\" class=\"DAV-img-box\"\u003e\u003cpath fill=\"#0047a7\" d=\"M128 32C92.7 32 64 60.7 64 96l0 256 64 0 0-256 384 0 0 256 64 0 0-256c0-35.3-28.7-64-64-64L128 32zM19.2 384C8.6 384 0 392.6 0 403.2C0 445.6 34.4 480 76.8 480l486.4 0c42.4 0 76.8-34.4 76.8-76.8c0-10.6-8.6-19.2-19.2-19.2L19.2 384z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e \n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eDownload Software \u0026amp; Drivers\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/davidastro.com\/pages\/askar-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eAskar 1-Year Warranty\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Askar","offers":[{"title":"Default Title","offer_id":48554702995741,"sku":"ASK-CM-C1C2","price":315.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Askar-Color-Magic-Filter-Pack.png?v=1717083872"}],"url":"https:\/\/davidastro.com\/collections\/narrowband-filters.oembed?page=5","provider":"David Astro","version":"1.0","type":"link"}