{"title":"Imaging Filters","description":"\u003cdiv\u003e\n  \u003cp\u003e\n    Not every imaging filter is narrowband or LRGB. Ultraviolet and infrared cut filters, luminance filters, methane band filters for planetary work and dedicated infrared pass filters each solve a specific problem, and several of them are more useful than their obscurity suggests. David Astro carries imaging filters in Canada, in Canadian inventory and shipped domestically.\n  \u003c\/p\u003e\n  \u003cp\u003e\n    These filters address particular situations rather than general imaging. Tell us what problem you are seeing and we will say whether one of them fixes it.\n  \u003c\/p\u003e\n\u003c\/div\u003e\n\u003c!-- more --\u003e\n\u003cdiv\u003e\n  \u003ch2\u003eSpecialist Imaging Filters\u003c\/h2\u003e\n  \u003cp\u003e\n    Each of these targets a specific defect or a specific wavelength range that general-purpose filters do not address.\n  \u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eUV and IR cut filters:\u003c\/strong\u003e Essential with refractors, which do not focus infrared at the same point as visible light. Without one, stars are bloated and soft in a way that looks like poor optics.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eLuminance filters:\u003c\/strong\u003e A broad visible-range filter with UV and IR blocking, used as the detail-carrying channel in LRGB imaging.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eInfrared pass filters:\u003c\/strong\u003e Pass only infrared, which cuts through atmospheric turbulence better than visible light and can sharpen planetary detail in poor seeing.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eMethane band filters:\u003c\/strong\u003e Very narrow filters at 889 nm revealing atmospheric structure on Jupiter, Saturn and the ice giants that is invisible in visible light.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eContinuum filters:\u003c\/strong\u003e Narrow green-band filters used for lunar and planetary imaging, reducing the effect of atmospheric dispersion.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAnti-halation and reflection considerations:\u003c\/strong\u003e Coating quality matters here too, since a filter close to the sensor can produce reflection artifacts around bright objects.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n  \u003ch2\u003eWhy Choose David Astro for Imaging Filters\u003c\/h2\u003e\n  \u003cp\u003e\n    These are problem-specific purchases, and the first question is whether you have the problem.\n  \u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eDiagnosis before recommendation:\u003c\/strong\u003e Send us a sample image and we will tell you whether bloated stars are an infrared problem, a spacing problem or a focus problem.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eRefractor advice:\u003c\/strong\u003e If you image with a doublet and have no UV\/IR cut filter, that is very often the cause of soft bright stars, and it is the cheapest fix in imaging.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSeeing-based advice:\u003c\/strong\u003e We will explain when an infrared pass filter genuinely helps planetary work and when it simply costs you resolution.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAuthorized dealer:\u003c\/strong\u003e Genuine filters with verified coatings and manufacturer warranty, in Canadian stock.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eShips from Canada:\u003c\/strong\u003e No duties or brokerage fees for Canadian buyers.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n  \u003ch2\u003eImaging Filters in Canada — Frequently Asked Questions\u003c\/h2\u003e\n  \u003cdl\u003e\n    \u003cdt\u003e\u003cstrong\u003eDo I need a UV\/IR cut filter?\u003c\/strong\u003e\u003c\/dt\u003e\n    \u003cdd\u003eWith any refractor, yes. ED doublets and even triplets do not bring infrared to the same focus as visible light, and an unfiltered sensor records that as bloated, soft stars.\u003c\/dd\u003e\n    \u003cdt\u003e\u003cstrong\u003eDoes an infrared filter help with bad seeing?\u003c\/strong\u003e\u003c\/dt\u003e\n    \u003cdd\u003eFor planetary imaging, often yes. Longer wavelengths are less affected by atmospheric turbulence, so an IR pass filter can produce sharper results on a poor night, at the cost of some resolution.\u003c\/dd\u003e\n    \u003cdt\u003e\u003cstrong\u003eWhat is a methane band filter for?\u003c\/strong\u003e\u003c\/dt\u003e\n    \u003cdd\u003eIt isolates a methane absorption band at 889 nm, revealing cloud structure on the gas giants that is invisible in visible light. It is a specialist filter needing substantial aperture and long exposures.\u003c\/dd\u003e\n    \u003cdt\u003e\u003cstrong\u003eWhy are my bright stars bloated?\u003c\/strong\u003e\u003c\/dt\u003e\n    \u003cdd\u003eMost commonly unblocked infrared in a refractor, sometimes filter reflections, sometimes back-focus error. Send us a crop and we will tell you which.\u003c\/dd\u003e\n  \u003c\/dl\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n  \u003ch2\u003eDiagnosing an imaging problem?\u003c\/h2\u003e\n  \u003cp\u003eSend us a sample crop and we will tell you what will actually fix it. Held in Canada, shipped fast.\u003c\/p\u003e\n\u003c\/div\u003e","products":[{"product_id":"celestron-uhc-lpr-filter-1-25","title":"Celestron UHC\/LPR Filter - 1.25\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eSelectively blocks mercury vapor, sodium vapor, and natural sky glow\u003c\/li\u003e\n\u003cli\u003eAchieves over 97% transmission of critical nebula emission lines\u003c\/li\u003e\n\u003cli\u003eFeatures a moderate 60nm passband for natural views with high contrast\u003c\/li\u003e\n\u003cli\u003eEfficient H-Alpha passband at 656nm for astrophotography\u003c\/li\u003e\n\u003cli\u003eSized for standard 1.25\" eyepieces and accessories\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\u003eCelestron UHC\/LPR Filter - 1.25\"\u003c\/h2\u003e\n\u003cp\u003eThe Celestron UHC\/LPR Filter for 1.25\" eyepieces delivers a dramatic increase in contrast by achieving over 97% transmission of key nebula wavelengths while suppressing common light pollution. Its 60nm passband provides a significant boost for telescopes in the 4\" to 11\" aperture range, darkening the sky without eliminating background star fields. This filter also includes an efficient H-Alpha passband at 656nm, making it a valuable tool for both visual observers and imagers.\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\u003eBlocking Unwanted Light with \u0026gt;97% Transmission\u003c\/h3\u003e\n\u003cp\u003eThis Ultra High Contrast (UHC) filter is engineered to isolate and reject specific wavelengths associated with urban skyglow—primarily from mercury and sodium-vapor streetlights—and the neutral oxygen that causes natural sky glow. While aggressively blocking these sources, the advanced multi-layer dielectric coatings allow more than 97% of the light from emission nebulae to pass through. The result is a significantly darker background sky, making faint structures in objects like the Orion Nebula (M42) or Lagoon Nebula (M8) pop into 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\u003eIonbeam-Hardened Durability for 1.25\" Barrels\u003c\/h3\u003e\n\u003cp\u003eCelestron employs plasma-assisted, Ionbeam-hardened coatings on the UHC\/LPR filter, creating an optical surface that is highly resistant to scratching and degradation from cleaning and environmental exposure. This modern coating technology ensures the filter's high transmission and sharp cutoffs are maintained for years of use. The precisely machined 1.25\" aluminum cell threads smoothly onto standard eyepieces, diagonals, and camera nosepieces without binding.\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 60nm Passband Optimized for Nebulae\u003c\/h3\u003e\n\u003cp\u003eThe filter's 60nm passband strikes a critical balance, offering a major contrast enhancement while maintaining a more natural-feeling view compared to ultra-narrowband filters. This moderate bandwidth allows enough of the stellar continuum through to keep star fields rich, which is especially appreciated by users of 4\" to 11\" telescopes. For imagers, the inclusion of the critical 656nm H-Alpha line means you can capture vital hydrogen-alpha data without needing a separate, dedicated filter.\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 Celestron UHC\/LPR 1.25\" filter improve my view of the Orion Nebula (M42) from the city?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFrom a light-polluted location, the Celestron UHC\/LPR filter will dramatically darken the greyish background sky, increasing the contrast between the nebula and its surroundings. This allows you to see fainter, extended structures in M42's outer wings and resolve more detail within the bright core of the Trapezium that would otherwise be washed out by city lights.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs this 1.25\" filter a good choice for my 8\" Schmidt-Cassegrain telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. Telescopes in the 4\" to 11\" range benefit significantly from this filter. On an 8\" SCT, the UHC\/LPR filter will provide a substantial contrast boost on emission and planetary nebulae without making the image too dim, preserving the brightness advantage of your telescope's aperture.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the difference between this Celestron UHC\/LPR filter and a broadband filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA UHC (Ultra High Contrast) filter like this one has a narrower passband (around 60nm) than a typical broadband or \"minus-violet\" filter. It more aggressively targets specific light pollution lines, resulting in a darker sky background and noticeably higher contrast on emission nebulae. Broadband filters offer a more subtle effect with a more natural color balance.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Celestron UHC\/LPR filter for astrophotography?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this filter is designed for both visual and imaging use. Its key advantage for imagers is the inclusion of an efficient H-Alpha passband at 656nm, allowing you to capture crucial red nebulosity with a color camera in a single shot, which many LPR filters block.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill this filter help me see galaxies better?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this filter is not recommended for galaxies. Galaxies are broadband objects, meaning they emit light across the entire visible spectrum. A UHC\/LPR filter works by blocking parts of that spectrum, which will dim the view of the galaxy as much as it dims the light pollution. It is designed specifically for emission nebulae.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat specific types of artificial light does the UHC\/LPR filter block?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe filter is designed to combat the most common sources of urban light pollution. This includes \u003cstrong\u003emercury vapor lights\u003c\/strong\u003e, \u003cstrong\u003ehigh-pressure sodium vapor lights\u003c\/strong\u003e, and \u003cstrong\u003elow-pressure sodium vapor lights\u003c\/strong\u003e. It also reduces the effects of natural \u003cstrong\u003esky glow\u003c\/strong\u003e caused by neutral oxygen emission.\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\u003eUHC\/LPR (Ultra High Contrast \/ Light Pollution Reduction)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBarrel Size\u003c\/td\u003e\n\u003ctd\u003e1.25\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePeak Transmission\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;97%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePassband\u003c\/td\u003e\n\u003ctd\u003e60nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-Alpha Passband\u003c\/td\u003e\n\u003ctd\u003e656nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoatings\u003c\/td\u003e\n\u003ctd\u003eMulti-layer dielectric, plasma assisted, Ionbeam hardened\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRecommended Aperture\u003c\/td\u003e\n\u003ctd\u003e4\" - 11\" (102mm - 280mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWarranty\u003c\/td\u003e\n\u003ctd\u003e2-Year Warranty\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=\"Celestron UHC\/LPR Filter - 1.25\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/F7424-A_uhc_lpr_filter_125_1.jpg?v=1680126759\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eUHC\/LPR Filter - 1.25\"\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\u003cimg class=\"DAV-img-box\" alt=\"Protective case for 1.25-inch filter\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/zwo-1-25-inch-filter-case.jpg?v=1782035905\"\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\u003ca href=\"https:\/\/davidastro.com\/pages\/celestron-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eCelestron 2-Year Limited Warranty\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Celestron","offers":[{"title":"Default Title","offer_id":44967149404445,"sku":"CEL-94123","price":132.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Celestron-UHC-LPR-Filter-1-25-in-94123-1__39582.1594230266.1280.1280.jpg?v=1684337240"},{"product_id":"celestron-uhc-lpr-filter-2","title":"Celestron UHC\/LPR Filter - 2\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eSelectively blocks light pollution from mercury and sodium vapor lights\u003c\/li\u003e\n\u003cli\u003eAchieves over 97% light transmission for maximum brightness\u003c\/li\u003e\n\u003cli\u003e60nm bandpass enhances nebula contrast while maintaining natural star fields\u003c\/li\u003e\n\u003cli\u003eOptimized for 2\" focusers and accessories\u003c\/li\u003e\n\u003cli\u003eIonbeam-hardened coatings for scratch resistance and 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\u003eCelestron UHC\/LPR Filter - 2\"\u003c\/h2\u003e\n\u003cp\u003eThe Celestron UHC\/LPR Filter for 2\" eyepieces dramatically increases contrast by selectively blocking artificial light pollution and natural sky glow, achieving over 97% transmission of critical nebula wavelengths within its 60nm passband. Optimized for telescopes from 4\" to 11\" in aperture, it darkens the sky background and includes a specific passband for the 656nm H-Alpha line, making faint emission structures visible from the city or deep-sky 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\u003eBlocking Key Light Pollution Lines in 4\" to 11\" Telescopes\u003c\/h3\u003e\n\u003cp\u003eThis Ultra High Contrast (UHC) filter is engineered to reject the specific wavelengths produced by mercury vapor, high and low-pressure sodium vapor lights, and the neutral oxygen emission that causes natural sky glow. By eliminating this unwanted light, the background sky appears significantly darker, allowing the faint light from emission nebulae to stand out. This targeted rejection is effective in telescopes from 4\" to 11\" in aperture, where maximizing every photon is critical.\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 60nm Passband Delivering \u0026gt;97% Peak Transmission\u003c\/h3\u003e\n\u003cp\u003eThe filter's design centers on a moderately wide 60nm passband, which allows it to boost nebula contrast without sacrificing a natural-looking star field. Within this window, advanced multi-layer dielectric coatings achieve a peak transmission of over 97%. This high efficiency ensures that views remain bright and detailed, preventing the dimming effect that can occur with less advanced filters and making it an ideal choice for smaller telescopes.\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\u003eHardened Coatings and a 656nm H-Alpha Passband for Imagers\u003c\/h3\u003e\n\u003cp\u003eCelestron utilizes plasma-assisted and Ionbeam-hardened coatings, creating a durable, scratch-resistant surface that withstands regular use and cleaning. For astrophotographers, the filter's design is especially valuable as it includes an efficient passband for the critical H-Alpha emission line at 656nm. This allows DSLR and color camera users to capture the deep reds of hydrogen-rich nebulae that are often lost in city light.\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\u003eUHC\/LPR vs. Standard Broadband Filters: A Clear Contrast Advantage\u003c\/h3\u003e\n\u003cp\u003eCompared to a typical broadband Light Pollution Reduction (LPR) filter, the Celestron UHC\/LPR provides a noticeable improvement in contrast on emission and planetary nebulae. While a broadband filter offers a more general reduction of light pollution, the UHC design more aggressively targets specific nuisance wavelengths.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSky Background:\u003c\/strong\u003e The sky view through the UHC\/LPR is significantly darker, making it easier to detect the faint, extended structures of objects like the Veil Nebula (NGC 6960).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNebula Detail:\u003c\/strong\u003e Emission nebulae appear more defined and \"pop\" from the background, revealing subtle shadings and structures that are washed out with a less selective filter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNatural View:\u003c\/strong\u003e The 60nm passband is wide enough to maintain relatively natural star colors, avoiding the heavy color cast associated with extremely narrow \"line\" filters.\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 difference between this Celestron UHC\/LPR and a standard broadband filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Celestron \u003cstrong\u003eUHC\/LPR (Ultra High Contrast\/Light Pollution Reduction)\u003c\/strong\u003e filter has a narrower passband (around 60nm) that more aggressively isolates the key wavelengths from emission nebulae while strongly rejecting light pollution. A standard broadband filter has a wider passband, resulting in a brighter but lower-contrast image. The UHC design produces a darker sky background and makes nebulae stand out more distinctly.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Celestron UHC\/LPR filter only for viewing nebulae?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile its primary purpose is to enhance emission, planetary, and reflection nebulae, it is not strictly limited to them. The filter can help darken the sky background and improve contrast on any deep-sky object, though the effect will be most dramatic on nebulae. It is not recommended for viewing galaxies or star clusters, as it will dim these objects without providing a significant contrast benefit.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill this filter help me see the Orion Nebula (M42) from my suburban backyard with an 8\" SCT?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. An 8\" SCT is an excellent instrument for this filter. The Celestron UHC\/LPR will significantly darken the washed-out suburban sky, dramatically improving the contrast of the Orion Nebula (M42). You will be able to see more of the faint, extended nebulosity and potentially resolve more detail within the Trapezium region.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eI have a 6\" Newtonian at a dark sky site. Is the Celestron UHC\/LPR filter still useful?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, even at a dark sky site, this filter is very effective. It works by blocking natural sky glow in addition to artificial light pollution. By using the filter on objects like the Lagoon Nebula (M8) or the Swan Nebula (M17), you will see a noticeable increase in contrast, making the nebulosity appear more detailed and defined against the blackness of space.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Celestron 2\" UHC\/LPR filter suitable for astrophotography?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, it is well-suited for imaging with color cameras like DSLRs or dedicated astronomy cameras. The filter's broader 60nm bandpass retains good star color, and its efficient transmission of the H-Alpha wavelength at 656nm is crucial for capturing the red emission regions in many popular deep-sky targets.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I attach and use the 2\" UHC\/LPR filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Celestron 2\" UHC\/LPR filter has standard 2\" filter threads (M48x0.75). It can be threaded directly onto the barrel of any 2\" eyepiece or onto a 2\" nosepiece for a camera. Simply screw it on until it is finger-tight and insert the eyepiece or camera into your telescope's focuser as usual.\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 Size\u003c\/td\u003e\n\u003ctd\u003e2\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eUHC\/LPR (Ultra High Contrast \/ Light Pollution Reduction)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePeak Transmission\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;97%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePassband\u003c\/td\u003e\n\u003ctd\u003e60nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-Alpha Passband\u003c\/td\u003e\n\u003ctd\u003e656nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoatings\u003c\/td\u003e\n\u003ctd\u003eMulti-layer dielectric, Ionbeam hardened\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRecommended Telescopes\u003c\/td\u003e\n\u003ctd\u003e4\" - 11\" aperture\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=\"Celestron UHC\/LPR Filter - 2\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/celestron-uhc-lpr-filter-2.jpg?v=1782200231\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eUHC\/LPR 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\u003cimg class=\"DAV-img-box\" alt=\"Protective Plastic Case for 2-inch Filter\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/2-inch-filter-case.jpg?v=1782200231\"\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.celestron.com\/pages\/drivers-and-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 Celestron 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\u003cp\u003eThis product is covered by Celestron's 2-Year Limited Warranty. For more details, please visit the \u003ca href=\"https:\/\/davidastro.com\/pages\/celestron-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eCelestron Warranty Policy\u003c\/a\u003e page.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Celestron","offers":[{"title":"Default Title","offer_id":44967149437213,"sku":"CEL-94124","price":174.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Celestron-UHC-LPR-Filter-2-in-94124-1__66083.1594230267.1280.1280.jpg?v=1684337242"},{"product_id":"explore-scientific-nebula-filter-cls-1-25","title":"Explore Scientific Nebula Filter CLS - 1.25\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eCity Light Suppression (CLS) Filter\u003c\/li\u003e\n\u003cli\u003eEnhances Contrast for Deep-Sky Objects\u003c\/li\u003e\n\u003cli\u003eAvailable in 1.25\" and 2\" Sizes\u003c\/li\u003e\n\u003cli\u003eIdeal for Viewing Nebulae and Galaxies\u003c\/li\u003e\n\u003cli\u003eThreads Directly into Standard Eyepieces\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\u003eExplore Scientific Nebula Filter CLS - 1.25\" \u0026amp; 2\"\u003c\/h2\u003e\n\u003cp\u003eThe Explore Scientific Nebula Filter CLS, available in standard 1.25\" and 2\" formats, is a general-purpose light pollution filter engineered to darken the sky background and significantly increase contrast on a wide range of deep-sky objects.\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\u003eBroadband Contrast Enhancement for Urban Skies\u003c\/h3\u003e\n\u003cp\u003eThis City Light Suppression (CLS) filter works by selectively blocking common wavelengths of artificial lighting, such as sodium and mercury vapor streetlights, which are the primary cause of urban skyglow. By rejecting this unwanted light while transmitting the key wavelengths emitted by deep-sky objects, the filter provides a dramatically darker sky background. This isolates faint nebulae and galaxies from the washed-out backdrop, making them easier to detect and observe.\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 General-Purpose Filter for Nebulae and Galaxies\u003c\/h3\u003e\n\u003cp\u003eUnlike narrowband filters that target specific emission lines, the CLS is a broadband filter designed for versatility. It improves the view of all types of deep-sky objects, including emission nebulae like the Orion Nebula (M42), reflection nebulae, and even broadband targets like the Andromeda Galaxy (M31). This makes the Explore Scientific CLS an excellent first filter for an observer looking for a single, effective tool to combat light pollution across the celestial catalog.\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 Explore Scientific CLS filter improve views from a suburban backyard?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Explore Scientific CLS filter darkens the sky background by blocking the most common wavelengths of light pollution from streetlights. This increases the contrast between your target object and the sky, making faint details in nebulae and galaxies more visible, even from moderately light-polluted areas.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the difference between the Explore Scientific CLS and a UHC filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA \u003cstrong\u003eCLS (City Light Suppression)\u003c\/strong\u003e filter is a broadband filter, meaning it passes a wider range of light, making it effective on galaxies and star clusters in addition to nebulae. A \u003cstrong\u003eUHC (Ultra High Contrast)\u003c\/strong\u003e filter is a narrowband filter that passes a much smaller range of light, primarily the OIII and H-beta lines from emission nebulae. A UHC provides higher contrast on those specific targets but is less effective for broadband sources like galaxies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Explore Scientific CLS filter for astrophotography?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the CLS filter is a popular choice for beginner to intermediate astrophotographers using color cameras (DSLR, Mirrorless, or One-Shot-Color astro cameras). It helps capture better data from light-polluted locations by reducing skyglow, leading to improved contrast and color balance in the final image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Explore Scientific CLS filter help me see the Orion Nebula (M42) with my 8\" Dobsonian?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. The Orion Nebula (M42) is a bright emission nebula that responds extremely well to a CLS filter. With an 8\" telescope, the filter will darken the surrounding sky significantly, making the faint, extended wings of the nebula pop into view and revealing more structure within the bright core.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Explore Scientific CLS filter affect views of the Andromeda Galaxy (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Andromeda Galaxy (M31) is a broadband target, meaning it emits light across the entire visible spectrum. The Explore Scientific CLS filter will help by dimming the skyglow around the galaxy, which can make its faint outer arms easier to trace. While it will slightly dim the galaxy itself, the contrast enhancement often results in a more detailed overall view, especially of the dust lanes near the core.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the Explore Scientific CLS filter thread into all standard 1.25\" and 2\" eyepieces?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. Both the 1.25\" and 2\" versions of the Explore Scientific CLS filter feature standard filter threads. They are designed to screw directly into the barrel of any corresponding 1.25\" or 2\" eyepiece or accessory, such as a filter wheel or camera nosepiece.\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\u003eGTIN\u003c\/td\u003e\n\u003ctd\u003e812257017195\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\", 2\"\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\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/explore-scientific-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eExplore Scientific Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Explore Scientific","offers":[{"title":"1.25\"","offer_id":44967202554141,"sku":"ES-310225","price":153.99,"currency_code":"CAD","in_stock":true},{"title":"2\"","offer_id":44967202586909,"sku":"ES-310220-1","price":168.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Explore-Scientific-Nebula-Filter-CLS-1-25-inch-310225-1__83920.1594240362.1280.1280.jpg?v=1684338886"},{"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":"william-optics-stc-ultra-layer-astro-multispectra-filter-48mm","title":"William Optics STC Ultra Layer Astro Multispectra Filter - 48mm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e48mm (M48) Filter Size\u003c\/li\u003e\n\u003cli\u003eMulti-Bandpass Light Pollution Suppression\u003c\/li\u003e\n\u003cli\u003ePasses H-α, H-β, and OIII Emission Lines\u003c\/li\u003e\n\u003cli\u003eSchott B270 Optical Glass Substrate\u003c\/li\u003e\n\u003cli\u003eSTC Ultra-Layer IBAD 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\u003eWilliam Optics STC Ultra Layer Astro Multispectra Filter - 48mm\u003c\/h2\u003e\n\u003cp\u003eThe 48mm William Optics STC Ultra Layer Astro Multispectra Filter is engineered to restore natural color and contrast to astrophotography by suppressing common mercury, sodium, and LED light pollution while transmitting crucial H-alpha, H-beta, and OIII nebula lines through its coated Schott B270 optical glass.\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\u003eRestoring Natural Color from Light-Polluted Skies\u003c\/h3\u003e\n\u003cp\u003eThis filter is designed as a direct response to the challenge of urban and suburban imaging. It isolates and blocks the most common sources of artificial skyglow—specifically mercury vapor, high-pressure sodium, and certain disruptive LED frequencies—that wash out faint deep-sky objects.\u003c\/p\u003e\n\u003cp\u003eBy removing the offending wavelengths, the STC Astro Multispectra filter darkens the sky background significantly. This allows you to use longer exposures from compromised locations, revealing faint nebulosity and galactic structure while preserving a natural color balance in stars and surrounding fields.\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 Imaging of H-α, H-β, and OIII Targets\u003c\/h3\u003e\n\u003cp\u003eWhile aggressively filtering light pollution, the STC Astro Multispectra preserves the most important wavelengths for astrophotography. The filter's bandpass is tailored to transmit the deep red of Hydrogen-alpha, the teal of Oxygen-III, and the blue-green of Hydrogen-beta with high efficiency.\u003c\/p\u003e\n\u003cp\u003eThis selective transmission dramatically increases the contrast between emission nebulae and the background sky. Objects like the North American Nebula (NGC 7000) or the Orion Nebula (M42) stand out with enhanced structure and saturation, producing images with greater depth and clarity even from a backyard observatory.\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\u003eSchott B270 Glass and Ion Beam Assisted Coatings\u003c\/h3\u003e\n\u003cp\u003eThe filter's optical foundation is premium Schott B270 glass, known for its clarity and homogeneity. This ensures that the filter imparts no degradation to your imaging system's resolution. Each surface is treated with STC’s proprietary Ultra Layer coatings applied via Ion Beam Assisted Deposition (IBAD).\u003c\/p\u003e\n\u003cp\u003eThis advanced coating process results in an exceptionally hard, durable, and environmentally stable surface that resists moisture and is easier to clean. The multi-layer coatings are also optimized to minimize reflections and prevent the halos around bright stars that can plague inferior filters, ensuring maximum light transmission of the desired wavelengths.\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 kind of light pollution does the WO STC Astro Multispectra filter block?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe filter is designed to suppress the most common sources of urban light pollution, including \u003cstrong\u003emercury vapor lamps\u003c\/strong\u003e, \u003cstrong\u003ehigh and low-pressure sodium vapor lamps\u003c\/strong\u003e, and certain wavelengths of \u003cstrong\u003eLED lighting\u003c\/strong\u003e that cause skyglow.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 48mm STC Astro Multispectra filter good for imaging galaxies like Andromeda (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, it is very effective for broadband targets like galaxies. By reducing skyglow, the filter increases the contrast between the galaxy's faint outer arms and the night sky. Unlike narrowband filters, it preserves the natural star colors in the galaxy's halo and core, making it an excellent choice for imaging M31 from suburban locations.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the STC Astro Multispectra filter affect star color compared to a UHC filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe STC Astro Multispectra is designed to produce more \u003cstrong\u003enatural star colors\u003c\/strong\u003e. While a traditional UHC (Ultra High Contrast) filter creates very high contrast on nebulae, it often does so at the cost of a strong blue-green color cast. This filter uses a multi-bandpass approach to let more of the stellar continuum through, resulting in a more balanced and photographically neutral image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the STC Astro Multispectra 48mm filter with a full-frame camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the \u003cstrong\u003e48mm (or 2-inch) filter size\u003c\/strong\u003e is ideal for use with full-frame DSLR or dedicated astronomy cameras. The large format prevents vignetting, ensuring the sensor is evenly illuminated from corner to corner, which is critical for wide-field astrophotography and Milky Way landscapes.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat makes the IBAD coatings on this filter special?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eIon Beam Assisted Deposition (IBAD)\u003c\/strong\u003e is an advanced coating process that creates extremely dense and durable layers on the optical surface. This makes the filter's coatings highly resistant to scratching from routine cleaning and degradation from environmental factors like humidity. It also yields superior anti-reflection performance, preventing halos and internal reflections.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs this filter suitable for imaging large targets like the North American Nebula (NGC 7000)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. This filter is perfect for large, emission-rich targets like the North American Nebula (NGC 7000) or the Veil Nebula complex. It allows the critical \u003cstrong\u003eH-alpha and OIII\u003c\/strong\u003e light from the nebula to pass through while blocking skyglow, making it ideal for capturing these objects with wide-field refractors or camera lenses.\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\u003eAstro Multispectra Light Pollution\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSize\u003c\/td\u003e\n\u003ctd\u003e48mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eThread\u003c\/td\u003e\n\u003ctd\u003eM48\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eGlass Substrate\u003c\/td\u003e\n\u003ctd\u003eSchott B270\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating Technology\u003c\/td\u003e\n\u003ctd\u003eSTC Ultra Layer IBAD\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\"\u003eWilliam Optics STC Ultra Layer Astro Multispectra Filter - 48mm\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\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":44967226573085,"sku":"WO-YF-STC-M48","price":328.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/William-Optics-STC-Ultra-Layer-Astro-Multispectra-Filter-48mm-YF-STC-M48-1__78203.1596133266.1280.1280.jpg?v=1684339482"},{"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. 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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. 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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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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. 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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. 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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. 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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. 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. 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":44967245807901,"sku":"CT-27008-1.25M","price":385.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967245840669,"sku":"CT-27008-31D","price":385.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967245873437,"sku":"CT-27008-36D","price":497.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967245906205,"sku":"CT-27008-2M","price":1162.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967245938973,"sku":"CT-27008-50D","price":1092.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967245971741,"sku":"CT-27008-50X50","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-OIII-8nm-Filter__01564.1596071516.1280.1280.jpg?v=1684339515"},{"product_id":"chroma-luminance-filter","title":"Chroma Luminance Filter","description":"\u003c!-- more --\u003e\u003cp\u003eLuminance filter for enhancing color rendering with RGB set\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":44967246070045,"sku":"CT-27040-1.25M","price":210.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967246102813,"sku":"CT-27040-31D","price":210.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967246135581,"sku":"CT-27040-36D","price":315.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967246168349,"sku":"CT-27040-2M","price":700.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967246201117,"sku":"CT-27040-50D","price":630.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967246233885,"sku":"CT-27040-50X50","price":665.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-Luminance-Filter__08679.1596071517.1280.1280.jpg?v=1684339517"},{"product_id":"chroma-red-filter","title":"Chroma Red Filter","description":"\u003c!-- more --\u003e\u003cp\u003eRed filter for color rendering with RGB set\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":44967247708445,"sku":"CT-27041-1.25M","price":210.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967247741213,"sku":"CT-27041-31D","price":210.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967247773981,"sku":"CT-27041-36D","price":315.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967247806749,"sku":"CT-27041-2M","price":700.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967247839517,"sku":"CT-27041-50D","price":630.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967247872285,"sku":"CT-27041-50X50","price":665.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-Red-Filter__89625.1596071518.1280.1280.jpg?v=1684339717"},{"product_id":"chroma-green-filter","title":"Chroma Green Filter","description":"\u003c!-- more --\u003e\u003cp\u003eGreen filter for color rendering with RGB set\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":44967247905053,"sku":"CT-27042-1.25M","price":210.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967247937821,"sku":"CT-27042-31D","price":210.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967247970589,"sku":"CT-27042-36D","price":315.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967248003357,"sku":"CT-27042-2M","price":700.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967248068893,"sku":"CT-27042-50D","price":630.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967248101661,"sku":"CT-27042-50X50","price":665.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-Green-Filter__89486.1596071518.1280.1280.jpg?v=1684339719"},{"product_id":"chroma-blue-filter","title":"Chroma Blue Filter","description":"\u003c!-- more --\u003e\u003cp\u003eBlue filter for color rendering with RGB set\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":44967248134429,"sku":"CT-27043-1.25M","price":210.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967248167197,"sku":"CT-27043-31D","price":210.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967248199965,"sku":"CT-27043-36D","price":315.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967248232733,"sku":"CT-27043-2M","price":700.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967248265501,"sku":"CT-27043-50D","price":630.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967248298269,"sku":"CT-27043-50X50","price":665.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-Blue-Filter__36624.1596071519.1280.1280.jpg?v=1684339721"},{"product_id":"chroma-loglow-filter","title":"Chroma LoGlow Filter","description":"\u003c!-- more --\u003e\u003cp\u003eBlocks common spectral lines from lighting sources. This filter provides balanced color for the visible spectrum while blocking most emission from metal-halide and vapor lamp sources which together contribute to sky glow.\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\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":44967248593181,"sku":"CT-27030-1.25M","price":385.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967248625949,"sku":"CT-27030-31D","price":385.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967248658717,"sku":"CT-27030-36D","price":497.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967248691485,"sku":"CT-27030-2M","price":707.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967248724253,"sku":"CT-27030-50D","price":637.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967248757021,"sku":"CT-27030-50X50","price":770.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-LoGlow-Filter__74050.1596071521.1280.1280.jpg?v=1684339519"},{"product_id":"chroma-clear-filter","title":"Chroma Clear Filter","description":"\u003c!-- more --\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":44967248822557,"sku":"CT-27044-1.25M","price":182.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967248855325,"sku":"CT-27044-31D","price":182.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967248888093,"sku":"CT-27044-36D","price":210.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967248920861,"sku":"CT-27044-2M","price":525.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967248953629,"sku":"CT-27044-50D","price":455.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967248986397,"sku":"CT-27044-50X50","price":490.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-Clear-Filter__90054.1596071523.1280.1280.jpg?v=1684339522"},{"product_id":"chroma-u-bessel-filter","title":"Chroma U-Bessel Filter","description":"\u003c!-- more --\u003e\u003cp\u003eUV photometric filter in UVBRI series\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":44967249051933,"sku":"CT-27050-1.25M","price":385.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967249084701,"sku":"CT-27050-31D","price":385.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967249117469,"sku":"CT-27050-36D","price":483.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967249150237,"sku":"CT-27050-2M","price":980.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967249183005,"sku":"CT-27050-50D","price":910.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967249215773,"sku":"CT-27050-50X50","price":1015.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-U-Bessel-Filter__84625.1596071523.1280.1280.jpg?v=1684339524"},{"product_id":"chroma-v-bessel-filter","title":"Chroma V-Bessel Filter","description":"\u003c!-- more --\u003e\u003cp\u003eGreen (Visible) photometric filter in UVBRI series\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":44967249281309,"sku":"CT-27051-1.25M","price":385.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967249314077,"sku":"CT-27051-31D","price":385.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967249346845,"sku":"CT-27051-36D","price":483.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967249379613,"sku":"CT-27051-2M","price":980.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967249412381,"sku":"CT-27051-50D","price":910.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967249445149,"sku":"CT-27051-50X50","price":1015.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-V-Bessel-Filter__56381.1596071524.1280.1280.jpg?v=1684339526"},{"product_id":"chroma-b-bessel-filter","title":"Chroma B-Bessel Filter","description":"\u003c!-- more --\u003e\u003cp\u003eBlue photometric filter in UVBRI series\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":44967249510685,"sku":"CT-27052-1.25M","price":385.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967249543453,"sku":"CT-27052-31D","price":385.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967249576221,"sku":"CT-27052-36D","price":483.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967249608989,"sku":"CT-27052-2M","price":980.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967249641757,"sku":"CT-27052-50D","price":910.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967249674525,"sku":"CT-27052-50X50","price":1015.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-B-Bessel-Filter__40887.1596071525.1280.1280.jpg?v=1684339528"},{"product_id":"chroma-r-bessel-filter","title":"Chroma R-Bessel Filter","description":"\u003c!-- more --\u003e\u003cp\u003eRed photometric filter in UVBRI series\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":44967249740061,"sku":"CT-27053-1.25M","price":385.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967249772829,"sku":"CT-27053-31D","price":385.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967249805597,"sku":"CT-27053-36D","price":483.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967249838365,"sku":"CT-27053-2M","price":980.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967249871133,"sku":"CT-27053-50D","price":910.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967249903901,"sku":"CT-27053-50X50","price":1015.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-R-Bessel-Filter__30129.1596071526.1280.1280.jpg?v=1684339726"},{"product_id":"chroma-i-bessel-filter","title":"Chroma I-Bessel Filter","description":"\u003c!-- more --\u003e\u003cp\u003eNIR photometric filter in UVBRI series\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":44967250034973,"sku":"CT-27054-1.25M","price":385.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967250067741,"sku":"CT-27054-31D","price":385.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967250100509,"sku":"CT-27054-36D","price":483.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967250133277,"sku":"CT-27054-2M","price":980.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967250166045,"sku":"CT-27054-50D","price":910.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967250198813,"sku":"CT-27054-50X50","price":1015.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-I-Bessel-Filter__54362.1596071527.1280.1280.jpg?v=1684339728"},{"product_id":"chroma-ubvri-filter-set","title":"Chroma UBVRI Filter Set","description":"\u003c!-- more --\u003e\u003cp\u003eUBVRI filter set for photometric imaging\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":44967250264349,"sku":"CT-27103-1.25M","price":1645.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967250297117,"sku":"CT-27103-31D","price":2275.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967250329885,"sku":"CT-27103-36D","price":2415.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967250362653,"sku":"CT-27103-2M","price":4620.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967250395421,"sku":"CT-27103-50D","price":4270.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967250428189,"sku":"CT-27103-50X50","price":4795.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-Bessel-UBVRI-Filters__13320.1596071528.1280.1280.jpg?v=1684339731"},{"product_id":"chroma-lrgb-filter-set","title":"Chroma LRGB Filter Set","description":"\u003c!-- more --\u003e\u003cp\u003eLuminance, Red, Green, and Blue astronomy filter set\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":44967250460957,"sku":"CT-27101-1.25M","price":735.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967250493725,"sku":"CT-27101-31D","price":735.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967250526493,"sku":"CT-27101-36D","price":1155.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967250559261,"sku":"CT-27101-2M","price":2695.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967250592029,"sku":"CT-27101-50D","price":2415.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967250624797,"sku":"CT-27101-50X50","price":2555.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-LRGB-Filters__96415.1596071530.1280.1280.jpg?v=1684339733"},{"product_id":"chroma-halrgb-filter-set","title":"Chroma HaLRGB Filter Set","description":"\u003c!-- more --\u003e\u003cp\u003e8nm H-alpha, Luminance, Red, Green, and Blue astronomy filter set\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 \/ 8nm","offer_id":44967250723101,"sku":"CT-27102-1.25M","price":1085.0,"currency_code":"CAD","in_stock":true},{"title":"1.25\" Round Mounted \/ 5nm","offer_id":44967250755869,"sku":"CT-HA5LRGB-1.25M","price":1344.0,"currency_code":"CAD","in_stock":true},{"title":"1.25\" Round Mounted \/ 3nm","offer_id":44967250788637,"sku":"CT-HA3LRGB-1.25M","price":1505.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted \/ 8nm","offer_id":44967250821405,"sku":"CT-27102-31D","price":1085.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted \/ 5nm","offer_id":44967250854173,"sku":"CT-HA5LRGB-31D","price":1344.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted \/ 3nm","offer_id":44967250886941,"sku":"CT-HA3LRGB-31D","price":1505.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted \/ 8nm","offer_id":44967250919709,"sku":"CT-27102-36D","price":1617.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted \/ 5nm","offer_id":44967250952477,"sku":"CT-HA5LRGB-36D","price":1988.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted \/ 3nm","offer_id":44967250985245,"sku":"CT-HA3LRGB-36D","price":2205.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted \/ 8nm","offer_id":44967251018013,"sku":"CT-27102-2M","price":3822.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted \/ 5nm","offer_id":44967251050781,"sku":"CT-HA5LRGB-2M","price":4025.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted \/ 3nm","offer_id":44967251083549,"sku":"CT-HA3LRGB-2M","price":4480.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted \/ 8nm","offer_id":44967251116317,"sku":"CT-27102-50D","price":3472.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted \/ 5nm","offer_id":44967251149085,"sku":"CT-HA5LRGB-50D","price":3675.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted \/ 3nm","offer_id":44967251181853,"sku":"CT-HA3LRGB-50D","price":4130.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted \/ 8nm","offer_id":44967251214621,"sku":"CT-27102-50X50","price":3626.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted \/ 5nm","offer_id":44967251247389,"sku":"CT-HA5LRGB-50X50","price":4452.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted \/ 3nm","offer_id":44967251280157,"sku":"CT-HA3LRGB-50X50","price":4690.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Transmission-Curve-of-Chroma-HaLRGB-Filters__04231.1596071532.1280.1280.jpg?v=1684339530"},{"product_id":"chroma-h-alpha-filter-optimized-for-f-3-3nm","title":"Chroma H-alpha Filter Optimized for f\/3 - 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\/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":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. They also can provide larger sizes and unique passbands upon request.\u003c\/p\u003e","brand":"Chroma","offers":[{"title":"1.25\" Round Mounted","offer_id":44967252754717,"sku":"CT-27006F3-1.25M","price":805.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967252820253,"sku":"CT-27006F3-31D","price":805.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967252853021,"sku":"CT-27006F3-36D","price":1085.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967252885789,"sku":"CT-27006F3-2M","price":1820.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967252918557,"sku":"CT-27006F3-50D","price":1750.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967252951325,"sku":"CT-27006F3-50X50","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__18267.1596071539.1280.1280.jpg?v=1684339747"},{"product_id":"baader-acf-dslr-astro-conversion-filter-for-canon-eos-300","title":"Baader ACF DSLR Astro Conversion Filter - for Canon EOS 300","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDesigned for Canon EOS 300 DSLR Astro-Conversion\u003c\/li\u003e\n\u003cli\u003eDramatically Improved Spectral Transmission for Astrophotography\u003c\/li\u003e\n\u003cli\u003eUnlocks Critical Hydrogen-Alpha (Hα) Wavelengths\u003c\/li\u003e\n\u003cli\u003ePlane-Optically Polished for Maximum Image Fidelity\u003c\/li\u003e\n\u003cli\u003eReplaces the Camera's Stock Internal Filter\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 ACF DSLR Astro Conversion Filter - for Canon EOS 300\u003c\/h2\u003e\n      \u003cp\u003eThe Baader ACF 1 Astro Conversion Filter is engineered specifically for the Canon EOS 300, replacing the stock internal filter to dramatically improve spectral transmission for astrophotography. This plane-optically polished filter is the key to unlocking the deep-red hydrogen-alpha wavelengths essential for capturing the true structure and extent of emission nebulae.\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\u003eUnlocking H-alpha: The Purpose of the Baader ACF Filter\u003c\/h3\u003e\n      \u003cp\u003eA standard DSLR camera's internal filter is designed to block infrared light and a significant portion of the deep-red spectrum to produce pleasing daytime images. This same filter, however, aggressively cuts off the 656nm Hydrogen-alpha line, which is the dominant wavelength emitted by the vast majority of nebulae. The Baader ACF filter corrects this by replacing the stock filter with one that has an \"astro-tuned\" transmission curve, allowing this vital wavelength to reach your camera's sensor.\u003c\/p\u003e\n      \u003cp\u003eWith this filter installed, your Canon EOS 300 can capture the faint, glowing hydrogen gas in objects like the North American Nebula (NGC 7000) or the Rosette Nebula (NGC 2244), revealing details and structures that are simply invisible to an unmodified camera.\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\u003ePlane Optical Polishing: Maintaining Image Sharpness\u003c\/h3\u003e\n      \u003cp\u003eInserting any filter into an optical path risks degrading the image, but the Baader ACF filter is manufactured to prevent this. It is plane-optically polished to a high standard, ensuring it does not introduce astigmatism, blur, or other aberrations into your images. This preserves the sharpness and resolution delivered by your telescope or camera lens.\u003c\/p\u003e\n      \u003cp\u003eThis level of optical quality means your stars remain tight, round points from edge to edge. The filter's only job is to alter the spectral transmission, not the geometric accuracy of the light cone, ensuring your final images are as sharp as your optics can deliver.\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\u003eStock vs. Astro-Modified: What the ACF Filter Changes for Your Canon EOS 300\u003c\/h3\u003e\n      \u003cp\u003eModifying your Canon EOS 300 with the Baader ACF filter fundamentally changes its behavior, turning it into a specialized instrument for astronomy. A stock camera will produce weak, muted reds when aimed at emission nebulae, often requiring extreme processing to show even a hint of structure. After modification, the H-alpha signal is dramatically stronger, making nebulae stand out with far less exposure time and noise.\u003c\/p\u003e\n      \u003cp\u003eThe primary trade-off is in daytime photography. The increased red sensitivity will shift the camera's color balance, requiring a custom white balance profile to produce natural-looking terrestrial images. For many, this modification dedicates the camera body to astrophotography, where its newfound sensitivity can be fully exploited.\u003c\/p\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\"\u003eWhat is the main benefit of installing the Baader ACF Filter in my Canon EOS 300?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe primary benefit is a massive increase in sensitivity to the \u003cstrong\u003eHydrogen-alpha (Hα) wavelength\u003c\/strong\u003e at 656nm. This allows your Canon EOS 300 to capture the faint, red light from emission nebulae, which is almost completely blocked by the camera's original factory filter.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Baader ACF Filter change my images of the Orion Nebula (M42) with my Canon EOS 300?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eWith an unmodified Canon EOS 300, the extensive outer loops of hydrogen gas in the Orion Nebula (M42) will appear faint and lack detail. After installing the Baader ACF filter, these structures will be significantly brighter and more defined in your exposures, revealing the full extent of the nebula with much greater contrast and color depth.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eCan I still use my Canon EOS 300 for normal daytime photography after installing the Baader ACF filter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, but with a critical adjustment. The increased red sensitivity will give daytime images a strong red cast. To correct this, you must create a \u003cstrong\u003ecustom white balance\u003c\/strong\u003e profile using a grey card. While usable, many astrophotographers choose to dedicate the modified camera body to astronomical use.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is \"plane optical polishing\" important for the Baader ACF conversion filter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003ePlane optical polishing ensures the filter is perfectly flat and free of optical defects. This is crucial because a low-quality filter can distort the light path, leading to \u003cstrong\u003eblurred stars and loss of detail\u003c\/strong\u003e. Baader's polishing maintains the high-resolution performance of your telescope and lenses.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eI use my Canon EOS 300 with an 80mm refractor. Will the Baader ACF filter introduce any optical problems?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo. Because the Baader ACF filter is plane-optically polished, it will not introduce any new aberrations like astigmatism or coma. It is designed to be optically transparent in terms of image geometry, so the sharp, high-contrast views from your 80mm refractor will be preserved.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs installing the Baader ACF filter a simple process?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eInstalling a DSLR conversion filter is a delicate and complex procedure that involves disassembling the camera body in a dust-free environment. It carries a risk of damaging the sensor or camera electronics. We strongly recommend having the \u003cstrong\u003einstallation performed by an experienced professional\u003c\/strong\u003e.\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 size\u003c\/td\u003e\n\u003ctd\u003eother\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter shape\u003c\/td\u003e\n\u003ctd\u003erectangular\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\u003eUnmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eColor Correction, H-alpha, IR-Cut, UV-Cut\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission Range\u003c\/td\u003e\n\u003ctd\u003e400 – 700 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003edielectrically coated, planeoptically polished\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    \n  \u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\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":"Default Title","offer_id":44967355842845,"sku":"BAA-2459211","price":124.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Baader-ACF-DSLR-Astro-Conversion-Filter-for-Canon-EOS-300-1__99449.1597110898.1280.1280.jpg?v=1684340980"},{"product_id":"baader-acf-dslr-astro-conversion-filter-for-canon-eos-350d-10d-20d-30d","title":"Baader ACF DSLR Astro Conversion Filter - for Canon EOS 350D\/10D\/20D\/30D","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDesigned for Canon EOS 350D, 10D, 20D, and 30D DSLRs\u003c\/li\u003e\n\u003cli\u003eImproves Spectral Transmission for Astrophotography\u003c\/li\u003e\n\u003cli\u003eUnlocks Sensitivity to Hydrogen-Alpha (Hα) Nebulae\u003c\/li\u003e\n\u003cli\u003ePlane-Optically Polished to Maintain Image Sharpness\u003c\/li\u003e\n\u003cli\u003eReplaces the Camera's Stock Internal Low-Pass Filter\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 ACF DSLR Astro Conversion Filter - for Canon EOS 350D\/10D\/20D\/30D\u003c\/h2\u003e\n\u003cp\u003eThe Baader ACF DSLR Astro Conversion Filter is a direct replacement for the stock low-pass filter in Canon EOS 350D, 10D, 20D, and 30D cameras. This plane-optically polished filter unlocks your DSLR's true deep-sky potential by providing improved spectral transmission, especially in the critical Hydrogen-alpha wavelength, turning a standard camera into a dedicated astronomical imaging tool.\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 H-Alpha for Deep-Sky Astrophotography\u003c\/h3\u003e\n\u003cp\u003eStandard DSLR cameras include an internal filter that aggressively blocks infrared light to ensure correct color balance for daytime photography. A side effect is that this filter also cuts off the vital 656nm Hydrogen-alpha line, the wavelength in which most emission nebulae shine brightest. The Baader ACF filter is engineered to replace the stock filter, providing a spectral window that allows this deep red light to reach your camera's sensor.\u003c\/p\u003e\n\u003cp\u003eBy installing this filter, you convert your camera into a powerful instrument for capturing faint, red nebulosity. Objects like the North American Nebula (NGC 7000) and the Rosette Nebula (NGC 2237), which are nearly invisible to an unmodified camera, will register with rich detail and contrast, revealing the vast hydrogen clouds that populate our galaxy.\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\u003ePlane-Polished Glass for Maintained Sharpness\u003c\/h3\u003e\n\u003cp\u003ePlacing any new optical element in a camera's light path carries the risk of degrading image resolution if not manufactured to high standards. Baader addresses this by ensuring the ACF filter is plane-optically polished. This process results in surfaces that are exceptionally flat and parallel, preventing any distortion of the focal plane.\u003c\/p\u003e\n\u003cp\u003eThis attention to optical quality means your stars remain pinpoint and fine details are preserved across the entire frame. The filter's purpose is to improve spectral response without compromising the sharpness your telescope and camera sensor are capable of delivering, ensuring your final images are both sensitive and sharp.\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 purpose of the Baader ACF Astro Conversion Filter for my Canon 20D?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis filter replaces your Canon 20D's original internal filter, which blocks most of the red light from deep-sky nebulae. The Baader ACF filter allows this critical \u003cstrong\u003eHydrogen-alpha light\u003c\/strong\u003e to pass through, dramatically increasing your camera's sensitivity for astrophotography of emission nebulae.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill installing the Baader ACF filter change how my Canon 350D works for daytime photography?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. After this modification, your camera's color balance will be strongly shifted toward red. While it's possible to correct this with a \u003cstrong\u003ecustom white balance\u003c\/strong\u003e, the camera is best considered a dedicated astronomy tool post-conversion. Autofocus with standard camera lenses may also be affected.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is this Baader filter better than just removing the stock filter from my Canon 10D?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eSimply removing the stock filter alters the camera's required back focus distance, making it impossible to reach infinity focus with many lenses and telescopes. The Baader ACF filter is a \u003cstrong\u003eplane-parallel replacement\u003c\/strong\u003e that maintains the correct optical path length, ensuring sharp focus while also protecting the exposed CMOS sensor from dust.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat objects will I image better with a Canon 30D modified with the Baader ACF filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYou will see the most significant improvement on \u003cstrong\u003eemission nebulae\u003c\/strong\u003e rich in Hydrogen-alpha. Expect stunning results on targets such as:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eThe Orion Nebula (M42)\u003c\/li\u003e\n\u003cli\u003eThe Lagoon Nebula (M8)\u003c\/li\u003e\n\u003cli\u003eThe North American Nebula (NGC 7000)\u003c\/li\u003e\n\u003cli\u003eThe California Nebula (NGC 1499)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the installation of the Baader ACF DSLR Astro Conversion Filter reversible?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe modification requires careful disassembly of your DSLR. While it is technically possible to reverse the process if you save the original filter, it is a delicate and complex procedure that carries a significant risk of damaging the camera. For this reason, it is generally considered a \u003cstrong\u003epermanent modification\u003c\/strong\u003e.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does \"plane optically polished\" mean for the Baader ACF filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt means the filter's surfaces are manufactured to be extremely flat and perfectly parallel to each other. This is a critical quality feature that \u003cstrong\u003eprevents image degradation\u003c\/strong\u003e. It ensures the filter will not introduce any distortions or blur, preserving the full sharpness and resolution of your optical system.\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\u003eDSLR Astro Conversion Filter (ACF)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatible Cameras\u003c\/td\u003e\n\u003ctd\u003eCanon EOS 350D, 10D, 20D, 30D\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Purpose\u003c\/td\u003e\n\u003ctd\u003eIncreases Hydrogen-Alpha (Hα) Sensitivity\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical Quality\u003c\/td\u003e\n\u003ctd\u003ePlane-Optically Polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter size\u003c\/td\u003e\n\u003ctd\u003eother\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter shape\u003c\/td\u003e\n\u003ctd\u003erectangular\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\u003eUnmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eColor Correction, H-alpha, IR-Cut, UV-Cut\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission Range\u003c\/td\u003e\n\u003ctd\u003e400 – 700 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003edielectrically coated, planeoptically polished\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 ACF DSLR Astro Conversion 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:\/\/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\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":"Default Title","offer_id":44967355908381,"sku":"BAA-2459212","price":139.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Baader-ACF-DSLR-Astro-Conversion-Filter-for-Canon-EOS-350D-10D-20D-30D-1__90920.1597110899.1280.1280.jpg?v=1684340982"},{"product_id":"baader-bcf-dslr-astro-conversion-filter-for-canon-eos","title":"Baader BCF DSLR Astro Conversion Filter - for Canon EOS","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eReplaces stock DSLR filter to dramatically increase H-alpha sensitivity\u003c\/li\u003e\n\u003cli\u003eEnables detailed imaging of emission nebulae\u003c\/li\u003e\n\u003cli\u003eDesigned for a wide range of Canon EOS APS-C cameras\u003c\/li\u003e\n\u003cli\u003eMaintains correct focus with standard camera lenses\u003c\/li\u003e\n\u003cli\u003eA permanent modification for dedicated astrophotography use\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 BCF DSLR Astro Conversion Filter - for Canon EOS\u003c\/h2\u003e\n\u003cp\u003eThe Baader BCF DSLR Astro Conversion Filter replaces the stock IR-cut filter in Canon EOS models like the 7D, 40D, and 50D, dramatically increasing their sensitivity to the critical Hydrogen-alpha wavelength. This modification is essential for capturing the faint, red structures in emission nebulae like the North American Nebula (NGC 7000) that a standard DSLR sensor cannot record. It transforms compatible cameras, including the 60D, 600D, and 1100D, into capable deep-sky imaging instruments.\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 Hydrogen-Alpha for Deep-Sky Imaging\u003c\/h3\u003e\n\u003cp\u003eA standard DSLR camera is engineered for daytime photography, which requires filtering out the infrared and ultraviolet light that human eyes don't see. Unfortunately, this stock filter also blocks most of the deep-red Hydrogen-alpha light that is the primary emission from the most iconic nebulae. The Baader BCF is specifically designed to replace this restrictive filter, opening a new window for your camera's sensor.\u003c\/p\u003e\n\u003cp\u003eBy installing the BCF, you allow this crucial wavelength to reach the sensor, revealing the intricate details, faint extensions, and true color of targets like the Orion Nebula (M42) and the Lagoon Nebula (M8). This is not a subtle change; it is the fundamental step in converting a consumer camera into a serious astrophotography tool.\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\u003eCompatibility for Canon EOS 7D, 40D, 50D, 60D, and More\u003c\/h3\u003e\n\u003cp\u003eThis Baader BCF filter is engineered for a precise fit within the sensor assemblies of a wide range of popular Canon EOS DSLR bodies. It is a direct replacement for the original filter, ensuring that autofocus and infinity focus with standard camera lenses are maintained after the conversion.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSupported Models:\u003c\/strong\u003e Canon EOS 7D, 40D, 50D, 60D, 400D, 450D, 500D, 550D, 600D, 650D, 1000D, and 1100D.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstallation Note:\u003c\/strong\u003e Replacing the internal filter is a delicate, irreversible process that requires disassembling the camera body. This modification should only be undertaken if you are comfortable with intricate electronics work or by a professional service.\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\u003eThe Astro-Conversion Advantage: Baader BCF vs. a Stock DSLR Filter\u003c\/h3\u003e\n\u003cp\u003eThe difference between an image taken with a stock DSLR and one with a Baader BCF-modified camera is night and day, especially on emission nebulae. A stock camera will struggle to record anything more than the brightest core of a nebula, often with weak, muddy colors. The modified camera captures the full extent of the object's glowing hydrogen gas.\u003c\/p\u003e\n\u003cp\u003eWhile a dedicated astronomy camera offers cooling and monochrome capabilities, a modified DSLR is a powerful and cost-effective entry into serious deep-sky imaging. The Baader BCF provides the most critical part of that conversion: enhanced red sensitivity. After modification, your camera will still function for daytime use, but will require a custom white balance to correct the color cast.\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 benefit of installing the Baader BCF in my Canon EOS camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary benefit is a massive increase in sensitivity to the \u003cstrong\u003eHydrogen-alpha wavelength\u003c\/strong\u003e. This allows your Canon DSLR to capture the faint, red light from emission nebulae, which is almost completely blocked by the camera's stock filter, transforming it into a powerful tool for deep-sky astrophotography.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Baader BCF filter allow my Canon 60D to photograph the Orion Nebula (M42) better?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. The Orion Nebula (M42) is rich in Hydrogen-alpha emissions. A standard Canon 60D will only capture the bright, central Trapezium region well, while the extensive outer loops of gas will appear faint and lack detail. With the Baader BCF installed, your 60D will record the full, vibrant red structure of the entire nebula complex.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eAfter installing the Baader BCF filter, can I still use my Canon 450D for normal daytime photography?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, but with a critical adjustment. After the conversion, daytime images will have a strong red color cast. To correct this, you must shoot using a \u003cstrong\u003ecustom white balance\u003c\/strong\u003e setting. By taking a reference photo of a neutral gray or white card, you can create a white balance profile that produces natural-looking colors for terrestrial subjects.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Baader BCF filter installation reversible?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile technically possible, the process is not considered easily reversible. It involves delicate disassembly of the camera and sensor assembly. It is best to consider this a \u003cstrong\u003epermanent modification\u003c\/strong\u003e dedicated to converting the camera for astrophotography.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhich Canon EOS models is the Baader BCF filter compatible with?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Baader BCF is designed for a range of Canon APS-C sensor DSLRs. Compatible models include the \u003cstrong\u003eCanon EOS 7D, 40D, 50D, 60D, 400D, 450D, 500D, 550D, 600D, 650D, 1000D, and 1100D\u003c\/strong\u003e.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does a Baader BCF-modified Canon 7D compare to a dedicated astronomy camera for imaging the Heart Nebula (IC 1805)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA Baader BCF-modified Canon 7D will dramatically outperform a stock DSLR on the Heart Nebula (IC 1805), capturing its extensive H-alpha structures. However, a dedicated astronomy camera typically offers sensor cooling to reduce thermal noise during long exposures, which will result in a cleaner final image with better signal-to-noise ratio. The modified DSLR is a fantastic, cost-effective step up, while a cooled astro camera is the next level for ultimate image quality.\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 size\u003c\/td\u003e\n\u003ctd\u003eother\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter shape\u003c\/td\u003e\n\u003ctd\u003erectangular\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\u003eUnmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eColor Correction, H-alpha, IR-Cut, UV-Cut\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission Range\u003c\/td\u003e\n\u003ctd\u003e400 – 700 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003edielectrically coated, planeoptically polished\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\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":"Default Title","offer_id":44967355941149,"sku":"BAA-2459213","price":114.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Baader-BCF-DSLR-Astro-Conversion-Filter-for-Canon-EOS-7D-40D-50D-60D-400D-450D-500D-550D-600D-650D-1000D-1100D-1__19322.1597110900.1280.1280.jpg?v=1684340985"},{"product_id":"baader-clear-focusing-filter","title":"Baader Clear Focusing Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eEnables precise focusing for dim narrowband filters\u003c\/li\u003e\n\u003cli\u003ePerfectly parfocal with other Baader Planetarium filters\u003c\/li\u003e\n\u003cli\u003eOptically polished to ensure no image degradation\u003c\/li\u003e\n\u003cli\u003eAvailable in multiple formats from 1.25\" mounted to 65x65mm square\u003c\/li\u003e\n\u003cli\u003eLPFC (Low Profile Filter Cell) on mounted versions for maximum compatibility\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 Clear Focusing Filter\u003c\/h2\u003e\n\u003cp\u003eThe Baader Clear Focusing Filter, available in multiple formats including 1.25\" and 2\" mounted cells and unmounted sizes up to 65x65mm, solves the most critical challenge of narrowband imaging: achieving perfect focus on a dim target. It is designed to be perfectly parfocal with Baader's line of imaging filters, allowing you to use a bright, full-spectrum star to achieve sharp focus before swapping to a restrictive line filter without any change in the focal point.\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 Parfocal Solution for Dim Narrowband Filters\u003c\/h3\u003e\n\u003cp\u003eNarrowband filters transmit such a tiny fraction of the visual spectrum that focusing can be an exercise in frustration. Stars become too faint for autofocus routines or to produce clear spikes on a Bahtinov mask. The Baader Clear Focusing Filter eliminates this problem by providing a bright, full-spectrum view for focusing.\u003c\/p\u003e\n\u003cp\u003eBecause this clear filter is manufactured to the exact same optical thickness as Baader's narrowband, LRGB, and other imaging filters, the focal plane does not shift when you switch between them. You can achieve critical focus once with the clear filter and be confident that every subsequent narrowband exposure is perfectly sharp, saving valuable time and eliminating wasted sub-exposures.\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\u003eOptically Polished Glass for Pinpoint Focus Accuracy\u003c\/h3\u003e\n\u003cp\u003eThis is not simply a blank piece of glass; it is a high-quality optical window. Each Baader Clear Focusing Filter is optically polished to maintain the integrity of your light path, ensuring that the focus you achieve is true and not compromised by optical imperfections. This prevents any degradation of your final image resolution.\u003c\/p\u003e\n\u003cp\u003eThe 1.25\" and 2\" mounted versions feature Baader's Low Profile Filter Cell (LPFC), designed to prevent vignetting and fit easily into any standard filter wheel or drawer. For users with specific needs, the filter is also available in a wide range of unmounted sizes, from 31mm round to 65x65mm square, to accommodate nearly any imaging setup.\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 do I need a Baader Clear Focusing Filter for narrowband imaging?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNarrowband filters, like H-alpha or OIII, block almost all light, making stars extremely dim and difficult to focus on. The \u003cstrong\u003eBaader Clear Focusing Filter\u003c\/strong\u003e is parfocal (maintains the same focus point) with these filters. This allows you to focus on a bright star with a full-spectrum view, then swap to your narrowband filter without needing to refocus, ensuring perfect sharpness.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Baader Clear Focusing Filter just an empty filter cell or blank glass?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo. It is a high-quality optical window that has been \u003cstrong\u003eoptically polished\u003c\/strong\u003e to a high standard. This ensures it does not introduce any distortion or aberrations into your optical train. Using a non-polished piece of glass would compromise the critical focus you are trying to achieve.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Baader Clear Focusing Filter be parfocal with filters from other brands?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNot necessarily. Parfocality depends on the precise mechanical thickness of the filter substrate. The \u003cstrong\u003eBaader Clear Focusing Filter\u003c\/strong\u003e is specifically designed to match the thickness of other Baader Planetarium filters. While it may be close with other brands, perfect parfocality is only guaranteed within the Baader system.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIf I'm imaging the Pelican Nebula (IC 5070) in SII, how does the Baader Clear Focusing Filter help?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eImaging the faint sulfur emissions of the Pelican Nebula requires long exposures through a very dim filter. Instead of struggling to focus on a faint star through the SII filter, you would use the \u003cstrong\u003eBaader Clear Focusing Filter\u003c\/strong\u003e to focus on a nearby bright star like Deneb. Once your focus is locked, you can swap to the SII filter in your filter wheel, slew to the nebula, and begin imaging, confident that your focus is perfect.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eI use a filter drawer with a fast f\/4 Newtonian. Is the Baader Clear Focusing Filter still effective?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, it is especially effective with fast systems. Fast optics have a very critical focus zone, making precise focus even more important. The \u003cstrong\u003eBaader Clear Focusing Filter\u003c\/strong\u003e allows you to use all available light to nail that critical focus point, which is extremely difficult to do with a dim narrowband filter at f\/4. The parfocal design ensures that focus is maintained when you insert your imaging filter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhich size of the Baader Clear Focusing Filter do I need?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe correct size depends on your filter wheel, filter drawer, or camera setup. The \u003cstrong\u003eBaader Clear Focusing Filter\u003c\/strong\u003e is available in several standard sizes:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25\" and 2\" Mounted:\u003c\/strong\u003e For standard filter wheels and focusers that accept threaded filters.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e31mm and 36mm Round Unmounted:\u003c\/strong\u003e Common sizes for 1.25\" filter wheels.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e50.4mm Round, 50x50mm Square, and 65x65mm Square Unmounted:\u003c\/strong\u003e For larger filter wheels designed for full-frame and medium-format sensors.\u003c\/li\u003e\n\u003c\/ul\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\u003eType\u003c\/td\u003e\n\u003ctd\u003eClear Focusing Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical Quality\u003c\/td\u003e\n\u003ctd\u003eOptically Polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Use\u003c\/td\u003e\n\u003ctd\u003eAchieving parfocal focus with narrowband and LRGB filters\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\u003eMounted Filter Cell\u003c\/td\u003e\n\u003ctd\u003eLow Profile Filter Cell (LPFC) on 1.25\" and 2\" versions\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 Usage\u003c\/td\u003e\n\u003ctd\u003eFocusing\/dust protection\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\u003eTransmission Range\u003c\/td\u003e\n\u003ctd\u003efull Spectrum\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003edielectrically coated, planeoptically polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType of Filter\u003c\/td\u003e\n\u003ctd\u003eClearglass (31mm Round Unmounted 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\"\u003eBaader Clear Focusing Filter (select 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_Anti-Reflective_LRGBC_Filters_Product_Information.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 Anti-Reflective LRGBC Filters Product Information\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":44967356039453,"sku":"BAA-2458415","price":63.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967356072221,"sku":"BAA-2458416","price":105.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted Filter","offer_id":44967356104989,"sku":"BAA-2458414","price":78.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted Filter","offer_id":44967356137757,"sku":"BAA-2459423","price":70.0,"currency_code":"CAD","in_stock":true},{"title":"50.4mm Round Unmounted Filter","offer_id":44967356170525,"sku":"BAA-2458420","price":121.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Filter","offer_id":44967356203293,"sku":"BAA-2458421","price":140.0,"currency_code":"CAD","in_stock":true},{"title":"65x65mm Square Filter","offer_id":44967356236061,"sku":"BAA-2459405","price":152.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader-Clear-Focusing-Filter-1__69249.1597110902.1280.1280.jpg?v=1684340987"},{"product_id":"baader-h-alpha-ccd-filter-35nm","title":"Baader H-Alpha CCD Filter -35nm","description":"\u003c!-- more --\u003e\u003cul\u003e\n\u003cli\u003ePremium grade H-alpha interline chip CCD-filter for fast optical systems f\/10 to f\/2.8\u003c\/li\u003e\n\u003cli\u003eIR-blocked\u003c\/li\u003e\n\u003cli\u003eNO halos, NO reflections, NO ghosting\u003c\/li\u003e\n\u003cli\u003eNon-aging sealed coating edges\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eBaader's new H-Alpha passfilter enables high-contrast deep sky images of H-II regions (such as the N. 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-ir-pass-filter-685nm","title":"Baader IR-Pass Filter 685nm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e685nm Infrared (IR) Pass Filter\u003c\/li\u003e\n\u003cli\u003eTransmits deep-red light starting from 670nm\u003c\/li\u003e\n\u003cli\u003eDramatically reduces the image-blurring effects of atmospheric seeing\u003c\/li\u003e\n\u003cli\u003eIdeal for high-resolution planetary, lunar, and solar imaging\u003c\/li\u003e\n\u003cli\u003eServes as a superior Luminance (L) filter for LRGB composites\u003c\/li\u003e\n\u003cli\u003eFeatures reflex-free anti-reflection coatings on an optically 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\u003eBaader IR-Pass Filter 685nm\u003c\/h2\u003e\n\u003cp\u003eThe Baader IR-Pass Filter 685nm isolates the deep-red and near-infrared spectrum, transmitting light that starts from 670nm. By blocking the shorter wavelengths of the conventional 400-700nm visual spectrum, this filter bypasses the worst of atmospheric turbulence, allowing planetary imagers to capture significantly sharper details that would otherwise be blurred by poor seeing.\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\u003eDefeating Atmospheric Turbulence with Light Beyond 685nm\u003c\/h3\u003e\n\u003cp\u003eAtmospheric seeing, the shimmering effect caused by air turbulence, is the primary obstacle to high-resolution imaging. Longer wavelengths of light are less susceptible to this distortion. The Baader 685nm IR-Pass filter exploits this physical principle by creating an image using only light from the most stable part of the spectrum, rendering dark structures on Mars, Jupiter, the Moon, and the Sun with much higher contrast and sharpness.\u003c\/p\u003e\n\u003cp\u003eBecause the filter's transmission begins at 670nm, it sits just at the edge of the visual range. This allows you to achieve focus with a sensitive camera before capturing the final, stabilized image in the near-infrared—a crucial advantage over deeper IR filters that are completely opaque to the human eye.\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\u003eLRGB Imaging: Creating a Superior Luminance Channel with the 685nm Filter\u003c\/h3\u003e\n\u003cp\u003eFor imagers using the LRGB (Luminance, Red, Green, Blue) method, the Baader 685nm IR-Pass serves as an exceptional luminance filter. On nights of unsteady seeing, capturing the 'L' channel through this filter ensures your image's foundational detail layer is as sharp as possible. This high-resolution monochrome data can then be combined with standard RGB data to produce a final color image that possesses far greater detail than one shot with a traditional broadband luminance filter.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptically Polished Substrate:\u003c\/strong\u003e Ensures the filter does not introduce any degradation to the optical path, preserving the performance of your telescope.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnti-Reflection Coatings:\u003c\/strong\u003e Both sides of the filter are treated with reflex-free anti-reflection coatings to maximize light transmission and prevent internal reflections from causing halos or ghosting on bright targets.\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 use the Baader 685nm IR-Pass filter instead of a regular Luminance filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA regular Luminance filter passes the entire visible spectrum (roughly 400-700nm), making it susceptible to atmospheric turbulence (seeing). The \u003cstrong\u003eBaader 685nm IR-Pass filter\u003c\/strong\u003e rejects these shorter, more easily scattered wavelengths, producing a much sharper, higher-contrast image that serves as a superior detail layer in an LRGB composite, especially on nights with poor seeing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I see through the Baader 685nm IR-Pass filter to focus?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eBarely. The filter begins transmitting at 670nm, which is at the very edge of human vision in the deep red. While you won't see much detail, a bright star or planet may be visible enough to aid in focusing, especially on a sensitive monochrome camera's live view. It is significantly easier to focus with than deeper IR-pass filters (like 742nm or 850nm) which are completely opaque.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of camera works best with the Baader 685nm IR-Pass filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA \u003cstrong\u003emonochrome CMOS or CCD camera\u003c\/strong\u003e is highly recommended. These cameras typically have much higher quantum efficiency in the near-infrared spectrum compared to one-shot color cameras, allowing for shorter exposures and better signal-to-noise ratio when using the Baader 685nm IR-Pass filter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Baader 685nm IR-Pass filter improve my images of Jupiter with an 8\" SCT?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAn 8\" SCT has enough aperture to resolve fine detail on Jupiter, but this is often limited by seeing. The \u003cstrong\u003eBaader 685nm IR-Pass filter\u003c\/strong\u003e will help stabilize the image, allowing you to capture sharper details in the cloud bands, the Great Red Spot, and smaller storms. By using it as your luminance channel, your final LRGB image of Jupiter will appear much more detailed than what you could capture with a standard UV\/IR cut filter alone.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Baader 685nm IR-Pass filter useful for solar imaging of sunspots?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. When used with a proper, full-aperture solar film or glass filter, the \u003cstrong\u003eBaader 685nm IR-Pass filter\u003c\/strong\u003e acts as a powerful seeing-reduction tool for white-light solar imaging. It will increase the contrast and sharpness of sunspot umbra\/penumbra details and solar granulation by minimizing atmospheric blurring.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo I still need RGB filters if I use the Baader 685nm IR-Pass filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The image from the Baader 685nm IR-Pass filter is monochrome and only captures detail, not color. To create a full-color image, you must capture separate data using Red, Green, and Blue filters and then combine them with the high-resolution data from the IR-Pass filter in post-processing software.\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\u003eInfrared (IR) Pass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCenter Wavelength\u003c\/td\u003e\n\u003ctd\u003e685nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCut-on Wavelength\u003c\/td\u003e\n\u003ctd\u003eStarts transmitting at ~670nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Use\u003c\/td\u003e\n\u003ctd\u003eHigh-Resolution Planetary, Lunar, Solar Imaging\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoatings\u003c\/td\u003e\n\u003ctd\u003eReflex-free anti-reflective\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eOptically Polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" and 2\" Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.01\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter shape\u003c\/td\u003e\n\u003ctd\u003eround\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)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eContrast Enhancement, IR-Pass, Planetary\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thickness (without cell)\u003c\/td\u003e\n\u003ctd\u003e2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003edielectrically coated, planeoptically polished\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 IR-Pass Filter 685nm (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\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003ePlastic Filter 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:\/\/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\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":44967357645085,"sku":"BAA-2458385","price":132.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967357677853,"sku":"BAA-2458386","price":209.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Baader-IR-Pass-Filter-685nm-1__95154.1597110927.1280.1280.jpg?v=1684341019"},{"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":"baader-photometric-ubvri-filter-set","title":"Baader Photometric UBVRI Filter Set","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eStandardized UBVRI Bessel passbands for scientific photometry\u003c\/li\u003e\n\u003cli\u003eEnables measurement of variable stars, asteroids, and exoplanet transits\u003c\/li\u003e\n\u003cli\u003ePrecision polished substrates for wavefront integrity\u003c\/li\u003e\n\u003cli\u003eAdvanced anti-reflection coatings to maximize signal\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\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 Photometric UBVRI Filter Set\u003c\/h2\u003e\n      \u003cp\u003eThe Baader Photometric UBVRI Filter Set provides the 5 essential passbands required for serious scientific photometry. This set is engineered to conform to the Johnson-Cousins-Bessel standard, ensuring your measurements of variable stars, asteroids, or exoplanet transits are consistent and comparable with data from professional observatories worldwide. By isolating specific regions of the spectrum—from the near-ultraviolet (U) to the near-infrared (I)—this 5-filter set transforms your imaging rig into a scientific instrument capable of producing publishable data.\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\u003eThe 5-Filter UBVRI Bessel System for Scientific Measurement\u003c\/h3\u003e\n      \u003cp\u003eUnlike filters designed for aesthetic deep-sky imaging, this set is built for quantitative analysis. The U (Ultraviolet), B (Blue), V (Visual), R (Red), and I (Infrared) filters are designed with specific passbands defined by the Bessel system, the modern standard for stellar photometry. This standardization is critical; it allows your observations to be reliably transformed and compared against global databases like that of the American Association ofVariable Star Observers (AAVSO).\u003c\/p\u003e\n      \u003cp\u003eUsing these filters, you can precisely measure the brightness changes of celestial objects over time. This is the foundation for creating light curves that reveal the physical nature of eclipsing binary stars, the rotation period of an asteroid, or the dimming caused by a transiting exoplanet.\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\u003eSubstrate and Coating Integrity for Repeatable Data\u003c\/h3\u003e\n      \u003cp\u003eIn photometry, any variation in the filter can introduce errors into the data. Baader Planetarium filters are manufactured using optically flat, homofocal substrates, ensuring that refocusing is minimized when switching between the five filters. This maintains a consistent optical path and reduces a major source of potential systematic error during an observation run.\u003c\/p\u003e\n      \u003cp\u003eEach filter is treated with advanced anti-reflection coatings to suppress halos and maximize light transmission within its designated passband. This results in a higher signal-to-noise ratio, allowing for more precise measurements of faint targets or subtle brightness variations, which is the difference between a noisy light curve and a clean detection.\u003c\/p\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\"\u003eWhat is the Baader Photometric UBVRI Filter Set primarily used for?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThis filter set is a specialized tool for \u003cstrong\u003escientific photometry\u003c\/strong\u003e, not for creating color images. Its purpose is to accurately measure the brightness of celestial objects through standardized passbands. This allows amateur and professional astronomers to study variable stars, measure asteroid rotation periods, detect exoplanet transits, and contribute data to scientific organizations like the AAVSO.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does the \"Bessel\" standard mean for these Baader UBVRI filters?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe \u003cstrong\u003eJohnson-Cousins-Bessel system\u003c\/strong\u003e is a set of standard photometric passbands used by astronomers globally. By adhering to the Bessel standard, the Baader UBVRI filters ensure that the data you collect is consistent and comparable with measurements made by other observers around the world. This is crucial for collaborative research and for submitting your observations to scientific databases.\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 for my Baader Photometric Filter Set?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe correct size depends entirely on your filter wheel and camera setup.\n      \u003c\/p\u003e\n\u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003e1.25\" and 31mm:\u003c\/strong\u003e Common for smaller sensors and filter wheels where vignetting is not a concern.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003e36mm:\u003c\/strong\u003e A popular size for many dedicated astronomy cameras with APS-C or smaller sensors, offering a good balance of size and illumination.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003e2\" and 50mm (Round\/Square):\u003c\/strong\u003e Necessary for cameras with full-frame (35mm) or larger sensors to prevent the filter from blocking light at the corners of the field.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003e65x65mm and 100x100mm:\u003c\/strong\u003e Reserved for professional-grade systems with very large format CCD or CMOS sensors.\u003c\/li\u003e\n      \u003c\/ul\u003e\n    Check your filter wheel's documentation to confirm the required filter size and whether it accepts mounted or unmounted filters.\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Baader UBVRI filters for visual observing or standard LRGB imaging?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo, these filters are not suitable for those purposes. Visually, the U, B, and I filters will produce very dim or unusual views. For imaging, they are not a substitute for LRGB (Luminance, Red, Green, Blue) filters, which are designed with significant overlap to produce natural-looking color images. UBVRI filters have distinctly separate passbands designed for measurement, not aesthetic color reproduction.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow would I use the Baader Photometric UBVRI set to measure the light curve of a star like Algol (Beta Persei)?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eTo measure the light curve of an eclipsing binary like \u003cstrong\u003eAlgol (Beta Persei)\u003c\/strong\u003e, you would typically use the V (Visual) filter, as most historical and comparative data is in this band. You would take a series of timed exposures of Algol before, during, and after its minimum brightness. Using photometry software, you would measure Algol's brightness relative to nearby, non-variable comparison stars in each frame. Plotting this measured brightness against time reveals the precise shape and timing of the eclipse, which is valuable scientific data.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eAre these Baader filters suitable for exoplanet transit photometry with an 11\" SCT?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, absolutely. An 11\" SCT is an excellent instrument for exoplanet transit work, and this Baader filter set is ideal for it. For exoplanet transits, the \u003cstrong\u003eR (Red) or I (Infrared) filters\u003c\/strong\u003e are often preferred. These longer wavelengths are less affected by atmospheric scintillation, leading to more stable and precise measurements of the tiny dip in starlight as a planet passes in front of its host star.\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\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, 31mm Unmounted, 36mm Unmounted, 50mm Unmounted, 50x50mm Square, 65x65mm Square, 100x100mm Square\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.03 (1.25\" Round Mounted)\u003cbr\u003e0.06 (2\" Round Mounted)\u003cbr\u003e0.02 (31mm Round Unmounted, 36mm Round Unmounted)\u003cbr\u003e0.07 (50mm Round Unmounted)\u003cbr\u003e0.10 (50x50mm Square Filter)\u003cbr\u003e0.16 (65x65mm Square Filter)\u003cbr\u003e0.39 (100x100mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter size\u003c\/td\u003e\n\u003ctd\u003e1.25 inch (1.25\" Round Mounted)\u003cbr\u003e2 inch (2\" Round Mounted)\u003cbr\u003e31 mm (31mm Round Unmounted)\u003cbr\u003e36 mm (36mm Round Unmounted)\u003cbr\u003e50.4 mm (50mm Round Unmounted)\u003cbr\u003e50 x 50 mm (50x50mm Square Filter)\u003cbr\u003e65 x 65 mm (65x65mm Square Filter)\u003cbr\u003e100 x 100 mm (100x100mm 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, 36mm Round Unmounted, 50mm Round Unmounted)\u003cbr\u003esquare (50x50mm Square Filter, 65x65mm Square Filter, 100x100mm 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, 36mm Round Unmounted, 50mm Round Unmounted, 50x50mm Square Filter, 65x65mm Square Filter, 100x100mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eCMOS, CCD, UBVRI\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType of Filter\u003c\/td\u003e\n\u003ctd\u003eBandpass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpecial Features\u003c\/td\u003e\n\u003ctd\u003eLife-Coat™ Warranty\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, 36mm Round Unmounted)\u003cbr\u003e3 mm (50mm Round Unmounted, 50x50mm Square Filter, 65x65mm Square Filter, 100x100mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCWL (Central Wavelength)\u003c\/td\u003e\n\u003ctd\u003eBessel-UBVRI\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission Range\u003c\/td\u003e\n\u003ctd\u003eTransmission according to Bessel\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\/15 to f\/1.8\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  \u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\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":44967358333213,"sku":"BAA-2961750","price":1018.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967358365981,"sku":"BAA-2961753","price":1515.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967358398749,"sku":"BAA-2961751","price":1114.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967358431517,"sku":"BAA-2961752","price":1231.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967358464285,"sku":"BAA-2961754","price":1667.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Filter","offer_id":44967358497053,"sku":"BAA-2961755","price":1784.0,"currency_code":"CAD","in_stock":true},{"title":"65x65mm Square Filter","offer_id":44967358529821,"sku":"BAA-2961756","price":2126.0,"currency_code":"CAD","in_stock":true},{"title":"100x100mm Square Filter","offer_id":44967358562589,"sku":"BAA-2961757","price":4776.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Baader-UBVRI-Filter-Set__28982.1635877141.1280.1280.jpg?v=1684341344"},{"product_id":"baader-photometric-ubvri-u-individual-filter","title":"Baader Photometric UBVRI-U Individual Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eConforms to the Johnson-Cousins\/Bessel U-Band Photometric Standard\u003c\/li\u003e\n\u003cli\u003eDesigned for Scientific Photometry of Variable Stars and Stellar Classification\u003c\/li\u003e\n\u003cli\u003ePlaneoptically Polished Substrate for Zero Image Degradation\u003c\/li\u003e\n\u003cli\u003eLife-Coat™ Hard Coatings for Durability and Resistance to Aging\u003c\/li\u003e\n\u003cli\u003eAvailable in Multiple Formats from 1.25\" Mounted to 100x100mm Unmounted\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 Photometric UBVRI-U Individual Filter\u003c\/h2\u003e\n\u003cp\u003eThe Baader Photometric UBVRI-U Filter provides scientifically rigorous ultraviolet data by adhering to the Bessel U-band standard, available in research-ready formats from 1.25\" mounted to 100x100mm unmounted for consistent stellar classification and variable star observation. This is not an imaging filter for creating color composites; it is a scientific instrument for collecting precise, repeatable measurements of stellar brightness in the near-ultraviolet spectrum.\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 U-Bessel Standard: Precision Ultraviolet Photometry\u003c\/h3\u003e\n\u003cp\u003eThis filter is designed to strictly conform to the U-band passband of the standardized Johnson-Cousins\/Bessel UBVRI system. This system is the bedrock of modern photometry, allowing astronomers worldwide to produce comparable data. The U-filter isolates a specific slice of the near-ultraviolet spectrum, critical for analyzing the hottest, most energetic stars and phenomena.\u003c\/p\u003e\n\u003cp\u003eBy using the Baader U-Filter, your measurements of O- and B-type stars, cataclysmic variables, or active galactic nuclei can be directly compared to professional datasets. It transforms your imaging setup into a tool for genuine scientific inquiry, enabling you to contribute to pro-am collaborations and long-term monitoring projects.\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\u003eResearch-Grade Optical Integrity for Data Stability\u003c\/h3\u003e\n\u003cp\u003eA filter's photometric accuracy depends on more than just its transmission curve; the physical substrate must be flawless. Each Baader Photometric Filter is made from a planeoptically polished substrate, ensuring it does not introduce any wavefront error to the optical path. The glass is perfectly homogeneous, guaranteeing consistent transmission across the entire field of view.\u003c\/p\u003e\n\u003cp\u003eTo ensure your data is valid for years to come, Baader employs advanced hard-coating techniques (Life-Coat™) that are dielectrically sealed at the edges. This process makes the coatings impervious to moisture and aging, preventing the bandpass from shifting over time—a critical requirement for any long-term variable star research.\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\u003ePhotometric U-Filter vs. Standard UV\/IR Cut Filters: A Scientific Instrument\u003c\/h3\u003e\n\u003cp\u003eIt's crucial to understand the distinction between this photometric filter and a standard UV\/IR cut (Luminance) filter used for deep-sky imaging. A UV\/IR cut filter is designed for broadband transmission of the entire visible spectrum while blocking the unfocused ends. Its goal is to maximize signal for aesthetically pleasing images.\u003c\/p\u003e\n\u003cp\u003eThe Baader U-Filter does the opposite: it aggressively blocks all visible and infrared light to isolate only the scientifically valuable U-band. Using this for general imaging would result in a very dim, monochromatic image with low signal. Its purpose is not visual appeal but quantitative measurement, making it an essential tool for the serious amateur astronomer focused on data collection.\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 Baader Photometric U-Filter primarily used for?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Baader Photometric U-Filter is a scientific instrument used for \u003cstrong\u003ephotometry\u003c\/strong\u003e—the precise measurement of starlight. Its primary applications include observing variable stars, classifying stars based on their color temperature (especially hot, blue O- and B-type stars), and studying energetic astronomical objects that are bright in ultraviolet light.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow is the Baader U-Bessel filter different from a standard UV\/IR cut filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA standard \u003cstrong\u003eUV\/IR cut filter\u003c\/strong\u003e is designed to pass the entire visible spectrum while blocking ultraviolet and infrared light, maximizing signal for color imaging. The \u003cstrong\u003eBaader U-Bessel filter\u003c\/strong\u003e does the opposite: it is designed to block all visible and IR light, passing only a very specific, standardized band of near-ultraviolet light for scientific measurement.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Baader Photometric U-Filter for visual observing or general astrophotography?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this filter is not suitable for visual use or for creating typical color astrophotos. Your eye is not sensitive to the ultraviolet wavelengths it passes, so everything would look dark. For imaging, it isolates such a narrow band of UV light that the resulting signal would be very low and not useful for creating a standard LRGB or narrowband image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is it important that the Baader U-Filter is \"photometric\"?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\"Photometric\" means the filter's transmission curve strictly adheres to the established scientific U-Bessel standard. This ensures that brightness measurements you take can be accurately compared to data from other observers and professional observatories around the world. It guarantees your data is consistent, repeatable, and scientifically valid.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow would I use the Baader Photometric U-Filter to study a variable star like Algol (Beta Persei)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYou would take a series of timed exposures of Algol using the Baader U-Filter with a monochrome camera. By measuring Algol's brightness relative to nearby, non-variable comparison stars in each frame, you can plot its light curve. The U-band is particularly useful for eclipsing binaries with hot stars like Algol, as it reveals temperature changes with high contrast.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eI want to classify hot stars in the Orion Nebula (M42) with my 11\" SCT. Is the Baader U-Filter the right choice?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, it is the ideal choice. The hot, young O- and B-type stars of the Trapezium Cluster within M42 are extremely bright in ultraviolet light. By measuring their brightness through U, B, and V filters, you can calculate their color indices (e.g., U-B) and determine their spectral type and temperature with high accuracy, even from a backyard setup.\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\u003ePhotometric Johnson-Cousins\/Bessel U-Band\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, 50mm Round Unmounted, 50x50mm Square Unmounted, 65x65mm Square Unmounted, 100x100mm Square Unmounted\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, 50mm Round Unmounted)\u003cbr\u003e0.02 (50x50mm Square Unmounted)\u003cbr\u003e0.03 (65x65mm Square Unmounted)\u003cbr\u003e0.08 (100x100mm Square Unmounted)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter size\u003c\/td\u003e\n\u003ctd\u003e1.25 inch (1.25\" Round Mounted)\u003cbr\u003e2 inch (2\" Round Mounted)\u003cbr\u003e31 mm (31mm Round Unmounted)\u003cbr\u003e36 mm (36mm Round Unmounted)\u003cbr\u003e50.4 mm (50mm Round Unmounted)\u003cbr\u003e50 x 50 mm (50x50mm Square Unmounted)\u003cbr\u003e65 x 65 mm (65x65mm Square Unmounted)\u003cbr\u003e100 x 100 mm (100x100mm Square Unmounted)\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, 36mm Round Unmounted, 50mm Round Unmounted)\u003cbr\u003esquare (50x50mm Square Unmounted, 65x65mm Square Unmounted, 100x100mm Square Unmounted)\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, 36mm Round Unmounted, 50mm Round Unmounted, 50x50mm Square Unmounted, 65x65mm Square Unmounted, 100x100mm Square Unmounted)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eCMOS, CCD, UBVRI\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpecial Features\u003c\/td\u003e\n\u003ctd\u003eLife-Coat™ Warranty\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, 36mm Round Unmounted)\u003cbr\u003e3 mm (50mm Round Unmounted, 50x50mm Square Unmounted, 65x65mm Square Unmounted, 100x100mm Square Unmounted)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCWL (Central Wavelength)\u003c\/td\u003e\n\u003ctd\u003eUBVRI-U\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission Range\u003c\/td\u003e\n\u003ctd\u003eTransmission according to Bessel\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\/15 to f\/1.8\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_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\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":44967358693661,"sku":"BAA-2961750U","price":231.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967358726429,"sku":"BAA-2961753U","price":372.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted","offer_id":44967358759197,"sku":"BAA-2961751U","price":255.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967358791965,"sku":"BAA-2961752U","price":271.0,"currency_code":"CAD","in_stock":true},{"title":"50mm Round Unmounted","offer_id":44967358824733,"sku":"BAA-2961754U","price":401.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Unmounted","offer_id":44967358857501,"sku":"BAA-2961755U","price":415.0,"currency_code":"CAD","in_stock":true},{"title":"65x65mm Square Unmounted","offer_id":44967358890269,"sku":"BAA-2961756U","price":488.0,"currency_code":"CAD","in_stock":true},{"title":"100x100mm Square Unmounted","offer_id":44967358923037,"sku":"BAA-2961757U","price":1056.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Baader-UBVRI-Filter-Set-Bandpass__47153.1635878681.1280.1280.jpg?v=1684341348"},{"product_id":"baader-fringe-killer-filter","title":"Baader Fringe-Killer Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eReduces violet\/blue color fringing in achromatic refractors\u003c\/li\u003e\n\u003cli\u003eBlocks unfocused near-infrared (NIR) light for sharper digital images\u003c\/li\u003e\n\u003cli\u003eMaintains a natural, balanced color profile\u003c\/li\u003e\n\u003cli\u003eConstructed with planeoptically polished glass to preserve image sharpness\u003c\/li\u003e\n\u003cli\u003eAvailable in standard 1.25\" and 2\" mounted 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\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 Fringe-Killer Filter\u003c\/h2\u003e\n      \u003cp\u003eThe Baader Fringe-Killer Filter, offered in standard 1.25\" and 2\" sizes, provides a powerful correction for the chromatic aberration common to achromatic refractors. By selectively blocking both unfocused blue-violet light and infrared wavelengths, this filter delivers a significant boost in contrast for planetary and lunar observing through any 1.25\" or 2\" eyepiece.\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\u003eCorrecting False Color in 1.25\" and 2\" Format\u003c\/h3\u003e\n      \u003cp\u003eAchromatic refractors, while offering excellent value, struggle to bring all colors to a single sharp focus, resulting in a distracting violet halo around bright objects. The Baader Fringe-Killer Filter targets this \"purple fringe\" by suppressing the unfocused blue-violet light, producing tighter star points and revealing subtle surface details that were previously washed out.\u003c\/p\u003e\n      \u003cp\u003eThe filter also incorporates a sharp cutoff in the near-infrared, a critical feature for digital imaging. Since CCD and CMOS sensors are sensitive to IR light that the human eye cannot see, this blocking action prevents stellar bloat and enhances overall image sharpness on planets and the Moon.\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\u003eAdvanced Coatings for a Bright, Color-Balanced Image\u003c\/h3\u003e\n      \u003cp\u003eUnlike simple color filters that produce a heavy color cast, the Fringe-Killer uses dozens of modern, plasma-assisted dielectric coatings to achieve its filtering effect. This complex construction allows it to be highly selective, reducing the offensive fringe while passing other wavelengths with maximum transmission, resulting in the brightest possible view.\u003c\/p\u003e\n      \u003cp\u003eEach filter is built on a planeoptically polished substrate. This ensures that the filter itself does not introduce any optical errors, preserving the sharpness of your telescope's optics. You can even place it well ahead of the focal plane, such as in front of a binoviewer, without degrading image definition.\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 Fringe-Killer vs. Simple Minus-Violet Filters\u003c\/h3\u003e\n      \u003cp\u003eA basic Minus-Violet (MV) filter offers a blunt solution, aggressively cutting blue light and often leaving the image with an unnatural yellow-green tint. The Baader Fringe-Killer is a more sophisticated tool designed for discerning observers.\u003c\/p\u003e\n      \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eColor Fidelity:\u003c\/strong\u003e The Fringe-Killer's primary advantage is its ability to maintain a much more neutral color balance. While reducing the violet fringe, it preserves the subtle blues, whites, and tans on objects like Jupiter and Saturn.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eTransmission:\u003c\/strong\u003e By being more selective, the Fringe-Killer passes more light across the visible spectrum, leading to a brighter image than many MV filters. This is especially important when observing at high magnification or with smaller aperture telescopes.\u003c\/li\u003e\n      \u003c\/ul\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\u003eUpgrading Achromats for High-Contrast Planetary Viewing\u003c\/h3\u003e\n      \u003cp\u003eThe practical effect of the Fringe-Killer is to elevate the performance of an affordable achromat to a level approaching a far more expensive instrument. The reduction in false color significantly improves contrast, allowing you to resolve finer details on celestial bodies.\u003c\/p\u003e\n      \u003cp\u003eWith the filter in place, you can push the magnification on your achromat to see delicate cloud bands on Jupiter, the Cassini Division in Saturn's rings, and the subtle textures within lunar craters. It is an essential upgrade that unlocks the true potential of your refractor for high-resolution observing.\u003c\/p\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\"\u003eHow does the Baader Fringe-Killer differ from a standard Minus-Violet filter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe Baader Fringe-Killer uses more advanced, selective coatings than a simple Minus-Violet filter. This allows it to reduce the distracting purple fringe while maintaining a much more \u003cstrong\u003enatural color balance\u003c\/strong\u003e and delivering a \u003cstrong\u003ebrighter image\u003c\/strong\u003e. A standard MV filter often creates a strong yellow or green cast over the entire view.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Baader Fringe-Killer make my telescope's view yellow?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo. While any filter that reduces violet light will cause a very slight color shift, the Fringe-Killer is specifically designed to provide excellent color balance. The view remains remarkably neutral, preserving the subtle, natural colors of planetary surfaces and stars, unlike harsher filters which impart a strong yellow-green tint.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Baader Fringe-Killer for astrophotography?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, the Fringe-Killer is excellent for imaging with a color camera and an achromatic refractor. In addition to controlling the visible violet fringe, it also blocks near-infrared (NIR) light. This is crucial because digital sensors are sensitive to NIR, which can cause bloated stars and reduced sharpness. The Fringe-Killer provides both corrections in a single filter.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat improvement can I expect from the Baader Fringe-Killer on Jupiter with my 4\" f\/8 refractor?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eWith a 4\" achromat, the Baader Fringe-Killer will provide a significant improvement on Jupiter. The purple halo around the planet will be greatly diminished, increasing contrast across the disk. This will make it easier to see the main equatorial belts, distinguish their coloration, and potentially spot finer details like festoons or ovals that were previously lost in the glare.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Baader Fringe-Killer useful on apochromatic (APO) refractors or reflectors?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eGenerally, no. The Fringe-Killer is designed specifically to correct the chromatic aberration inherent in \u003cstrong\u003eachromatic refractors\u003c\/strong\u003e. Apochromatic (APO) refractors and reflector telescopes (like Newtonians or SCTs) are already highly corrected for false color, so this filter would provide little to no benefit and would slightly dim the image unnecessarily.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhere should I place the Baader Fringe-Killer in my optical train for viewing the Moon?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eFor visual use, the Baader Fringe-Killer should be threaded directly onto the barrel of your \u003cstrong\u003e1.25\" or 2\" eyepiece\u003c\/strong\u003e. Because it is made with planeoptically polished glass, its placement is not critical, and it will not degrade image sharpness. When viewing the bright lunar limb, it will eliminate the purple fringe, making the view much more comfortable and revealing fine details right up to the edge.\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\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" and 2\" Round Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Use\u003c\/td\u003e\n\u003ctd\u003eChromatic Aberration Reduction\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoatings\u003c\/td\u003e\n\u003ctd\u003eMulti-layer Dielectric\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003ePlaneoptically Polished Glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.01\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)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eColor Correction, IR-Cut\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType of Filter\u003c\/td\u003e\n\u003ctd\u003eBandpass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thickness (without cell)\u003c\/td\u003e\n\u003ctd\u003e2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission Range\u003c\/td\u003e\n\u003ctd\u003emultiple bands (see spectral image)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003ePhantom Coating® Group, planeoptically polished\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\"\u003eBaader Fringe-Killer Filter (in 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    \u003cli class=\"DAV-grid-item\"\u003e\n      \u003cdiv\u003e\n        \u003cp class=\"DAV-item-title\"\u003eProtective Filter 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\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\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 Policy\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"1.25\" Round Mounted","offer_id":44967362101533,"sku":"BAA-2458370","price":134.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967362134301,"sku":"BAA-2458375","price":194.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Baader-Fringe-Killer-Filter-1__75286.1597110982.1280.1280.jpg?v=1684341115"},{"product_id":"baader-semi-apo-filter","title":"Baader Semi-APO Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eReduces chromatic aberration in achromatic refractors\u003c\/li\u003e\n\u003cli\u003eEnhances contrast on the Moon, planets, and bright stars\u003c\/li\u003e\n\u003cli\u003eImproves star sharpness by tightening blue\/violet focus\u003c\/li\u003e\n\u003cli\u003eMaintains a more natural color balance than stronger \"minus-violet\" filters\u003c\/li\u003e\n\u003cli\u003eAvailable in standard 1.25\" and 2\" mounted 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 Semi-APO Filter\u003c\/h2\u003e\n\u003cp\u003eThe Baader Semi-APO Filter is an optical upgrade for any standard achromatic refractor, available in both 1.25\" and 2\" formats. By selectively filtering unfocused violet and blue light, this filter effectively eliminates the distracting purple halos (chromatic aberration) that plague achromatic designs, delivering views with significantly improved sharpness and contrast—approaching the color fidelity of a much more expensive apochromatic (APO) 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\u003eUpgrading Achromat Optics: Reducing Chromatic Aberration\u003c\/h3\u003e\n\u003cp\u003eAchromatic refractors, while offering excellent value, struggle to bring all colors of light to the same focal point. The Baader Semi-APO filter corrects this fundamental limitation by gently attenuating the violet and blue wavelengths that cause the most prominent color fringing. This creates a cleaner, more focused image without the strong color cast introduced by more aggressive \"minus-violet\" filters, preserving a more natural 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 Visual Result: Tighter Stars and Sharper Planetary Detail\u003c\/h3\u003e\n\u003cp\u003eWith the purple halo removed, the improvement in image definition is immediately obvious. Bright stars like Vega or Sirius resolve into tight, crisp points instead of bloated disks, and the blackness of space appears darker right up to the star's edge. On the Moon and planets, this translates to higher contrast; you can more easily discern fine crater details along the lunar terminator and subtle cloud bands on Jupiter that were previously washed out by the violet glow.\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 Semi-APO vs. Minus-Violet Filters: A More Natural Color Balance\u003c\/h3\u003e\n\u003cp\u003eWhile a standard minus-violet filter can also reduce color fringing, it often does so at the cost of imparting a strong yellow or greenish tint to the image. The Baader Semi-APO filter uses a more sophisticated coating design that produces a far more neutral color balance.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMinus-Violet Filter Trade-off:\u003c\/strong\u003e Stronger violet suppression often leads to an unnatural, yellow-tinted view, which can be distracting on objects like the Moon or Jupiter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBaader Semi-APO Advantage:\u003c\/strong\u003e Its milder, more targeted filtering provides a significant reduction in chromatic aberration while keeping the visual field looking natural and balanced. It's a refinement filter, not just a color blocker.\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\"\u003eHow does the Baader Semi-APO Filter improve views of Jupiter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eJupiter is a bright target that shows significant purple fringing in achromatic refractors. The \u003cstrong\u003eBaader Semi-APO Filter\u003c\/strong\u003e eliminates this fringe, increasing the contrast between the planet's cloud belts and zones. This makes it easier to spot subtle details like festoons and the Great Red Spot, which are often obscured by the unfocused violet light.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Baader Semi-APO Filter make my view of the Moon sharper?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The Moon's bright limb is a classic test for chromatic aberration. The \u003cstrong\u003eBaader Semi-APO Filter\u003c\/strong\u003e removes the soft violet halo along the edge, making the entire disk appear sharper and more defined. This increased contrast is especially noticeable when observing fine details like rilles and small craterlets along the terminator.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Baader Semi-APO Filter useful on an apochromatic (APO) or ED refractor?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this filter is not necessary for high-end APO or ED refractors. Those telescopes are already designed to correct for chromatic aberration internally. The Semi-APO filter is specifically engineered to improve the optical shortcomings of standard two-element achromatic refractors.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Baader Semi-APO Filter for astrophotography?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile designed for visual use, the \u003cstrong\u003eBaader Semi-APO Filter\u003c\/strong\u003e can be beneficial for imaging with a color camera and an achromatic refractor. It helps to reduce star bloat caused by unfocused blue and violet light, resulting in tighter stars and better overall image quality. It functions similarly to a UV\/IR cut filter but with a more targeted effect on the visible violet spectrum.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat's the difference between the Baader Semi-APO and a Fringe-Killer filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Baader Fringe-Killer filter is a more aggressive filter that blocks a larger portion of the blue\/violet spectrum. It offers stronger correction but introduces a more noticeable yellow color cast. The \u003cstrong\u003eSemi-APO Filter\u003c\/strong\u003e is a more refined version that provides excellent correction while maintaining a much more neutral and pleasing color balance.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Baader Semi-APO filter work on my Dobsonian or SCT?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this filter is not designed for reflector or catadioptric telescopes like Dobsonians, Newtonians, SCTs, or Maksutovs. These designs do not suffer from chromatic aberration, so the filter would provide no benefit and would only slightly dim the image.\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 Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Round Mounted, 2\" Round Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.01\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)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eCCD, Color Correction, IR-Cut\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType of Filter\u003c\/td\u003e\n\u003ctd\u003eBandpass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thickness (without cell)\u003c\/td\u003e\n\u003ctd\u003e1 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission Range\u003c\/td\u003e\n\u003ctd\u003emultiple bands (see spectral image)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003ePhantom Coating® Group, planeoptically polished\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\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":44967364624669,"sku":"BAA-2458398","price":132.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967364657437,"sku":"BAA-2458399","price":238.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Baader-Semi-APO-Filter-1__73856.1597110994.1280.1280.jpg?v=1684341176"},{"product_id":"baader-uhc-s-l-booster-filter","title":"Baader UHC-S\/L-Booster Filter - CMOS-Optimized","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eTargets modern LED and broadband light pollution\u003c\/li\u003e\n\u003cli\u003eOptimized blue transmission to reject artificial skyglow\u003c\/li\u003e\n\u003cli\u003eServes as a \"pre-filter\" for finding objects before using narrowband\u003c\/li\u003e\n\u003cli\u003eHigh-transmission coatings for bright, high-contrast views\u003c\/li\u003e\n\u003cli\u003eCMOS-optimized to suppress reflections and halos\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 UHC-S\/L-Booster Filter - CMOS-Optimized\u003c\/h2\u003e\n\u003cp\u003eThe Baader UHC-S\/L-Booster Filter is engineered to combat modern light pollution, specifically targeting the broad-spectrum blueish skyglow produced by LED streetlights. By isolating the critical H-beta and OIII emission lines of nebulae while rejecting artificial light, this filter dramatically darkens the sky background for deep-sky observers. Its CMOS-optimized design ensures high transmission and suppresses internal reflections, making it an essential tool for both visual astronomy and digital imaging from the city or suburbs.\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 Modern LED Skyglow\u003c\/h3\u003e\n\u003cp\u003eMany older \"light pollution\" filters were designed to block the narrow emission lines of sodium and mercury-vapor streetlights. The widespread adoption of white LED lighting has rendered these designs less effective. The Baader UHC-S\/L-Booster filter features a transmission curve specifically shaped to reject the broad blue-white spectrum of LEDs, restoring the deep-sky contrast that modern light sources wash 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\u003eThe Ideal Visual Partner for OIII Filters\u003c\/h3\u003e\n\u003cp\u003eWhile a narrowband OIII filter delivers maximum contrast on planetary nebulae, its extremely restricted view can make initially locating a faint target difficult. The UHC-S\/L-Booster acts as the perfect complement, offering a wider, brighter field of view that still provides significant contrast enhancement. You can use the UHC-S\/L to find your target and study its broader context before switching to a narrowband filter for fine detail.\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 High Transmission and Reflection Control\u003c\/h3\u003e\n\u003cp\u003eModern CMOS sensors are notoriously reflective, often creating halos and other artifacts around bright stars when used with standard filters. The \"CMOS-Optimized\" designation means this filter incorporates advanced anti-reflection coatings and precise dielectric layers. This design maintains high light transmission on critical nebula lines while minimizing the internal reflections that can ruin an astrophoto.\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\u003eUHC-S\/L-Booster vs. Traditional Broadband Filters\u003c\/h3\u003e\n\u003cp\u003eMany entry-level \"sky-glow\" filters offer a very modest reduction in light pollution and can introduce unwanted color casts. They provide a slight improvement over no filter at all.\u003c\/p\u003e\n\u003cp\u003eThe Baader UHC-S\/L-Booster is a more specialized tool. Its primary advantage is its targeted rejection of the specific light spectrum produced by modern LEDs, making it far more effective in contemporary urban and suburban settings. While a generic filter might offer a slight dimming of the background, the UHC-S\/L-Booster is engineered to surgically remove the most problematic wavelengths of artificial light.\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 Baader UHC-S\/L-Booster over a standard UHC filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary advantage is its optimization for \u003cstrong\u003emodern light pollution\u003c\/strong\u003e. While traditional UHC filters are excellent at blocking older sodium and mercury vapor lamp emissions, the Baader UHC-S\/L-Booster is specifically designed to also block the broad-spectrum blueish glow from LED streetlights, resulting in a darker sky background in most urban and suburban areas today.\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 UHC-S\/L-Booster filter?\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 the filter's advanced anti-reflection coatings and construction. These features are designed to prevent halos, reflections, and other artifacts that can occur when imaging with highly reflective modern CMOS sensors. This ensures cleaner, higher-quality images, especially around bright stars.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Baader UHC-S\/L-Booster for both visual observing and astrophotography?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, it is designed for both. For \u003cstrong\u003evisual use\u003c\/strong\u003e, it dramatically increases the contrast of emission nebulae against a light-polluted sky. For \u003cstrong\u003eastrophotography\u003c\/strong\u003e, it serves as an excellent L-Booster (luminance booster), isolating key nebula emission lines while its CMOS-optimized design ensures clean, artifact-free data.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow would the Baader UHC-S\/L-Booster improve my view of the Orion Nebula (M42) from the suburbs?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFrom a suburban location, the skyglow from LED lights can wash out the faint, extended nebulosity of M42. The Baader UHC-S\/L-Booster will selectively block this artificial light, making the sky background appear much darker. This increases the contrast and allows the faint outer loops and intricate details of the Orion Nebula to become visible where they were previously lost in the glare.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWith my 8\" SCT, why use the Baader UHC-S\/L-Booster for planetary nebulae instead of just an OIII filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile an OIII filter provides the highest contrast on a planetary nebula like the Ring Nebula (M57), its narrow bandpass and dim view can make finding the object challenging in a long focal-length telescope like an SCT. The Baader UHC-S\/L-Booster provides a brighter, wider field, making it much easier to locate the nebula first. It also passes both OIII and H-Beta lines, offering a more complete initial view before you switch to the OIII filter for detailed study.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhen should I choose the Baader UHC-S\/L-Booster instead of a true narrowband filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eChoose the Baader UHC-S\/L-Booster when your goal is general deep-sky observing from a light-polluted area, especially for objects that emit strongly in both H-Beta and OIII (like M42 or the Lagoon Nebula, M8). It is also the superior choice for locating objects before switching to a more restrictive narrowband filter. A true narrowband filter is better when you need to isolate a single emission line for maximum contrast or for specific imaging palettes (like the Hubble Palette).\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\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)\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)\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)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eCMOS, Contrast Enhancement, Light Pollution Reduction, Luminance (1.25\" Round Mounted, 2\" Round Mounted, 31mm Round Unmounted Filter, 36mm Round Unmounted Filter)\u003cbr\u003eContrast Enhancement, Light Pollution Reduction, Luminance (50.4mm Round Unmounted Filter, 50x50mm Square Filter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType of Filter\u003c\/td\u003e\n\u003ctd\u003eBandpass\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)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission Range\u003c\/td\u003e\n\u003ctd\u003emultiple bands (see spectral image)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003eReflex-Blocker™ hard coated, dielectrically coated, planeoptically polished\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 UHC-S\/L-Booster 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\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eProtective Filter 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:\/\/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\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":44967365017885,"sku":"BAA-2961560","price":143.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967365050653,"sku":"BAA-2961563","price":247.0,"currency_code":"CAD","in_stock":true},{"title":"31mm Round Unmounted Filter","offer_id":49144651645213,"sku":"BAA-2961561","price":166.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted Filter","offer_id":44967364919581,"sku":"BAA-2961562","price":201.0,"currency_code":"CAD","in_stock":true},{"title":"50.4mm Round Unmounted Filter","offer_id":44967364952349,"sku":"BAA-2961564","price":255.0,"currency_code":"CAD","in_stock":true},{"title":"50x50mm Square Filter","offer_id":44967364985117,"sku":"BAA-2961565","price":401.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader-UHC-S-L-Booster-Filter-1__73722.1597110998.1280.1280.jpg?v=1684341377"},{"product_id":"baader-uv-ir-cut-l-filter-cmos-optimized","title":"Baader UV\/IR-CUT \/ L-Filter CMOS Optimized","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eBlocks unwanted UV and IR wavelengths for sharper stars\u003c\/li\u003e\n\u003cli\u003eOptimized for modern CMOS sensors to prevent star bloat\u003c\/li\u003e\n\u003cli\u003eServes as a high-transmission Luminance (L) filter for LRGB imaging\u003c\/li\u003e\n\u003cli\u003eAdvanced anti-reflection coatings minimize halos and internal reflections\u003c\/li\u003e\n\u003cli\u003eAvailable in standard 1.25\" and 2\" mounted 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 UV\/IR-CUT \/ L-Filter CMOS Optimized\u003c\/h2\u003e\n\u003cp\u003eThe Baader UV\/IR-CUT \/ L-Filter CMOS Optimized is engineered to solve the specific challenges of modern astrophotography sensors. By providing a sharp cutoff of infrared wavelengths that cause star bloat in highly red-sensitive CMOS chips, this filter ensures your luminance data produces tight, focused stars. It combines the function of a standard UV\/IR cut filter with coatings and transmission characteristics tailored to deliver maximum signal and contrast, serving as the ideal L-filter in any LRGB imaging 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\u003eEngineered for Modern Sensors: Taming IR Bloat and Halos\u003c\/h3\u003e\n\u003cp\u003eStandard UV\/IR cut filters often have a gradual cutoff in the near-infrared, allowing unwanted IR light to reach the sensor. Because modern CMOS sensors have high sensitivity in this region, this leakage results in bloated, soft stars, obscuring fine detail. The Baader CMOS Optimized filter provides a much sharper cutoff, effectively blocking this problematic IR light to keep stars pinpoint sharp.\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 High-Transmission Window for Visible Light\u003c\/h3\u003e\n\u003cp\u003eAs a luminance filter, its primary job is to collect the maximum amount of detail-rich signal across the visible spectrum. Baader's advanced coatings ensure high transmission from blue to red, capturing faint galaxy arms and nebular structures without introducing a color cast. This unfiltered, broadband signal forms the high-resolution backbone of your final LRGB color 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\u003eBaader Anti-Reflection and Coating Technology\u003c\/h3\u003e\n\u003cp\u003eImaging with filters placed close to the sensor, as in many filter wheels and drawers, increases the risk of halos from internal reflections. The Baader CMOS Optimized L-Filter features carefully designed anti-reflection coatings to suppress these artifacts. This ensures that bright stars like Vega or Sirius don't produce distracting rings or ghost images, preserving the clean, dark background of 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\u003eBaader CMOS L-Filter vs. Standard UV\/IR Cut Filters\u003c\/h3\u003e\n\u003cp\u003eWhile both filters block UV and IR, a standard UV\/IR cut filter is often just a protective element, while the Baader CMOS-optimized version is a precision imaging tool. The key differences lie in the steepness of the IR cutoff and the quality of the anti-reflection coatings.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard UV\/IR Cut Filter:\u003c\/strong\u003e Often has a slow, gradual IR cutoff, leading to star bloat with sensitive CMOS cameras. May lack the advanced anti-reflection coatings needed to prevent halos in modern imaging trains.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBaader CMOS Optimized L-Filter:\u003c\/strong\u003e Features a very sharp IR cutoff specifically to keep stars tight on CMOS sensors. Incorporates superior anti-reflection coatings to eliminate halos caused by reflections between the filter and sensor cover glass.\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 do I need the Baader \"CMOS Optimized\" L-Filter for my camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eModern CMOS sensors are highly sensitive to near-infrared light, which is not focused at the same point as visible light by most telescopes. A standard L-filter can leak this IR light, causing stars to appear bloated and soft. The \u003cstrong\u003eBaader CMOS Optimized L-Filter\u003c\/strong\u003e has a much sharper cutoff, blocking this IR light to produce significantly tighter, sharper stars.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Baader UV\/IR-CUT \/ L-Filter help with my refractor's chromatic aberration?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, it is essential for refractors, especially achromatic and apochromatic doublets. These telescopes are not designed to bring ultraviolet and infrared light to a sharp focus. By blocking these wavelengths, the \u003cstrong\u003eBaader UV\/IR-CUT \/ L-Filter\u003c\/strong\u003e prevents a soft, unfocused halo from forming around stars and improves overall image contrast, even in high-end triplet APOs.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Baader L-Filter for visual observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile designed for imaging, it can be beneficial for visual use, particularly with refractors or reflector telescopes that have corrector lenses. By cutting out-of-focus UV and IR light, it can subtly improve the snap and contrast of the view, though the effect is much more dramatic in photography.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Baader L-Filter improve my images of the Andromeda Galaxy (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFor a broadband target like the Andromeda Galaxy (M31), the Baader L-Filter allows you to capture the maximum amount of light from the core, dust lanes, and faint outer arms. By ensuring stars remain sharp pinpoints instead of bloated orbs, it allows the fine details and faint structures of the galaxy to stand out with greater clarity and resolution.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs this Baader filter parfocal with other Baader filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eBaader Planetarium designs its filter sets to be parfocal, meaning you should not have to significantly refocus when switching between them. This is a critical feature for automated imaging, saving time and preventing lost frames due to focus shift between your L, R, G, B, and narrowband filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Baader L-Filter work in my fast f\/2 RASA or Hyperstar system?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. Baader's CMOS-optimized filters are designed to work well in fast optical systems without significant band-shifting. The high-quality anti-reflection coatings are also crucial in these setups, where the filter is placed very close to the sensor, making it effective at preventing internal reflections and halos around bright stars.\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 Options\u003c\/td\u003e\n\u003ctd\u003e2\" Round Mounted, 1.25\" Round Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.01\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)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eCMOS, CCD, IR-Cut, Luminance, UV-Cut\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType of Filter\u003c\/td\u003e\n\u003ctd\u003eBandpass\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\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCWL (Central Wavelength)\u003c\/td\u003e\n\u003ctd\u003eUV\/IR-Cut\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission Range\u003c\/td\u003e\n\u003ctd\u003e420 – 685 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\/15 to f\/1.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eThis product is a filter only. No other accessories are included.\u003c\/p\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\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":"2\" Round Mounted","offer_id":44967365935389,"sku":"BAA-2961573","price":158.0,"currency_code":"CAD","in_stock":true},{"title":"1.25\" Round Mounted","offer_id":50170696204573,"sku":"BAA-2961570","price":95.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader-UV-IR-CUT-L-Filter-1__54067.1597111001.1280.1280.jpg?v=1684341393"},{"product_id":"zwo-ir-850nm-pass-filter-1-25","title":"ZWO IR 850nm Pass Filter – 1.25\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003ePasses Infrared Light \u0026gt; 850nm\u003c\/li\u003e\n\u003cli\u003eDramatically Steadies Planetary Views in Poor Seeing\u003c\/li\u003e\n\u003cli\u003eEnables Daylight Planetary and Lunar Imaging\u003c\/li\u003e\n\u003cli\u003eStandard 1.25\" (31.75mm) Threaded Filter Cell\u003c\/li\u003e\n\u003cli\u003eIncludes Protective Plastic Case\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 850nm IR Pass Filter - 1.25\"\u003c\/h2\u003e\n\u003cp\u003eThe ZWO 850nm IR Pass Filter isolates a specific slice of the near-infrared spectrum, transmitting only wavelengths longer than 850nm. Housed in a standard 1.25\" (31.75mm) threaded cell, this filter is a specialized tool for high-resolution planetary and lunar imaging, effectively bypassing the atmospheric turbulence that blurs details in the visible spectrum.\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\u003eCut Through Bad Seeing at 850nm\u003c\/h3\u003e\n\u003cp\u003eAtmospheric turbulence, or \"seeing,\" is the primary obstacle to sharp planetary detail. Because longer wavelengths of light are less scattered by air currents, imaging at 850nm and beyond dramatically stabilizes the image. This allows you to resolve finer details in Jupiter's cloud bands, the Cassini Division in Saturn's rings, and subtle craterlets on the Moon, even when seeing conditions are poor or your target is low on the horizon.\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\u003eDaylight Planetary Imaging Beyond 850nm\u003c\/h3\u003e\n\u003cp\u003eBy aggressively blocking all visible light below 850nm, this filter renders the daytime sky nearly black to an IR-sensitive camera. This unique capability opens up the possibility of imaging bright planets like Venus and Jupiter during daylight hours. The result is a high-contrast image of the planet against a dark background, free from the glare of the blue sky.\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 850nm vs. 685nm IR Pass: Which to Choose?\u003c\/h3\u003e\n\u003cp\u003eZWO offers multiple IR Pass filters, and the choice depends on your conditions and camera. The 850nm filter is the more specialized of the two most common options.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eZWO 685nm IR Pass:\u003c\/strong\u003e This filter allows more light to reach the sensor, resulting in a brighter image and shorter exposure times. It is a great all-around choice for improving detail in average-to-poor seeing and works well with a broader range of monochrome cameras.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eZWO 850nm IR Pass:\u003c\/strong\u003e This filter is the ultimate seeing-killer. When conditions are exceptionally turbulent, the 850nm passband delivers the steadiest possible image. The trade-off is a significantly dimmer signal, which requires a camera with high IR sensitivity and potentially higher gain settings to achieve focus and capture data.\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\u003eDesigned for IR-Sensitive Cameras in a 1.25\" Cell\u003c\/h3\u003e\n\u003cp\u003eThis filter is designed for astro-imaging with an IR-sensitive monochrome or color camera; the human eye is not sensitive to 850nm light, so it cannot be used for visual observation. Its performance is directly tied to the quantum efficiency of your camera in the near-infrared. For best results, pair the ZWO 850nm IR Pass filter with a mono camera known for strong IR response. The industry-standard 1.25\" (31.75mm) threaded cell fits any standard 1.25\" filter wheel or nosepiece.\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 ZWO 850nm filter improve imaging of Jupiter on a turbulent night?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eOn nights with poor seeing, the Earth's atmosphere blurs the fine details of planets like Jupiter. The ZWO 850nm filter blocks the shorter, more easily scattered visible wavelengths and only lets the steadier, longer-wavelength infrared light through. This results in a much more stable image on your sensor, allowing you to capture sharper details in the Great Red Spot and equatorial cloud bands that would otherwise be a shimmering mess.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the ZWO 850nm IR Pass filter with my color astronomy camera to image the Moon?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, if the camera has good near-infrared sensitivity. Beyond 850nm the red, green and blue pixels of a color sensor respond almost equally, so ZWO notes that a color camera such as the ASI224MC or ASI185MC can be used like a mono camera with this filter (keep white balance at 50). The signal is dim, so a camera with strong IR response, mono or color, gives the best results.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the ZWO 850nm filter suitable for visual observation?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo. The human eye cannot see light at a wavelength of 850nm. Looking through an eyepiece with this filter attached will result in a completely black field of view. It is a specialized tool designed exclusively for use with an infrared-sensitive astronomy camera.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main difference between the ZWO 850nm and a 685nm IR Pass filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary difference is how aggressively they cut off visible light.\n\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eA \u003cstrong\u003e685nm filter\u003c\/strong\u003e is a good general-purpose choice, offering a significant improvement in seeing with a relatively bright signal.\u003c\/li\u003e\n\u003cli\u003eThe \u003cstrong\u003e850nm filter\u003c\/strong\u003e provides maximum seeing stabilization for the most turbulent conditions but passes much less light, requiring a very IR-sensitive camera and longer exposures or higher gain.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy would I want to image planets during the day with the ZWO 850nm filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eImaging during the day allows you to capture planets when they are at their highest point in the sky, where atmospheric distortion is at a minimum. The ZWO 850nm filter makes this possible by blocking the visible light that makes the sky appear blue, effectively creating a dark background for your camera and allowing bright planets like Venus or Jupiter to be imaged in high contrast.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the ZWO 850nm filter require a filter wheel?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, a filter wheel is not required. The filter's 1.25\" cell is threaded to screw directly onto any standard 1.25\" camera nosepiece or accessory. However, using it in a filter wheel makes it easy to switch between the 850nm filter and other filters (like LRGB) without disassembling your imaging train.\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-850IR1.25\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eIR Pass \/ Luminance\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\u003eFormat\u003c\/td\u003e\n\u003ctd\u003eThreaded, Round\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePassband\u003c\/td\u003e\n\u003ctd\u003e\u0026gt; 850nm\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 850nm IR Pass Filter in 1.25\" Cell\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\"\u003ePlastic Filter 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\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":"Default Title","offer_id":44967439859997,"sku":"ZWO-850IR1-25","price":40.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/ZWO-IR-850nm-Pass-Filter-1-25-inch-1__82864.1596910056.1280.1280.jpg?v=1684341991"},{"product_id":"zwo-lrgb-optimized-filters","title":"ZWO LRGB Optimized Filters","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e1.25\" (31.75mm) Threaded Filter Set\u003c\/li\u003e\n\u003cli\u003eGreater than 92% Transmission at Passband\u003c\/li\u003e\n\u003cli\u003eBalanced 1:1:1 RGB Exposure Weighting\u003c\/li\u003e\n\u003cli\u003e1\/4 Wavefront Polished Optical Glass\u003c\/li\u003e\n\u003cli\u003e700-1100nm Infrared Wavelength Cut-Off\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 LRGB 1.25\" Premium Filter Set\u003c\/h2\u003e\n\u003cp\u003eThe ZWO LRGB 1.25\" Premium Filter Set delivers exceptional color fidelity and high-contrast data by ensuring over 92% light transmission across the critical passbands. Each filter is fine-optically polished to 1\/4 wavefront accuracy to preserve the sharpness of your telescope's optics. The set's precise 700-1100nm infrared cut-off and approximately 1:1:1 RGB color weighting simplify both image capture and processing, yielding brilliant results with modern CMOS cameras.\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\u003eOver 92% Transmission \u0026amp; 1:1:1 Color Balance\u003c\/h3\u003e\n\u003cp\u003eThis filter set captures faint signal efficiently, with each filter transmitting more than 92% of the light in its target wavelength. This high throughput reduces necessary exposure times, improving your overall signal-to-noise ratio. The coatings are engineered for an approximate 1:1:1 RGB color balance, allowing you to use similar exposure durations for each color channel and spend less time correcting color gradients in 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\u003e1\/4 Wavefront Accuracy for Maximum Sharpness\u003c\/h3\u003e\n\u003cp\u003eA filter is part of your telescope's optical train, and low-quality glass can degrade an otherwise sharp image. ZWO polishes these filters to a 1\/4 wavefront standard, ensuring they do not introduce aberrations or soften star images. Paired with multiple layers of anti-reflection coatings, this optical precision maintains high contrast and protects fine details in planetary and deep-sky targets.\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\u003ePrecision Off-Band Blocking Down to 700nm\u003c\/h3\u003e\n\u003cp\u003eModern monochrome CMOS sensors are highly sensitive to infrared light, which can cause star bloat and wash out color data if not properly blocked. This LRGB set features a sharp IR cut-off at 700nm, eliminating this issue entirely. The filters also incorporate a small spectral gap between the transmission bands, which helps to reject common sources of urban light pollution and further darken the sky background.\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 Premium vs. Standard LRGB Filters\u003c\/h3\u003e\n\u003cp\u003eWhile ZWO's standard filters offer an excellent entry into LRGB imaging, the Premium set is a significant step up in optical design for the discerning astrophotographer.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBetter Color Separation:\u003c\/strong\u003e The Premium filters have sharper cutoffs, which reduces wavelength overlap between channels for richer, more distinct colors.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHigher Transmission:\u003c\/strong\u003e With \u0026gt;92% transmission, the Premium filters gather more light than the standard versions, enabling deeper shots in the same amount of time.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSimplified Processing:\u003c\/strong\u003e The 1:1:1 color balance of the Premium set is a key advantage, removing the need for significant color weighting corrections that are often required with the standard set.\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 advantage of the ZWO Premium LRGB filters over the standard set?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary advantages are higher transmission (\u0026gt;92%), better color separation from superior coatings, and a carefully engineered 1:1:1 color balance. This balance simplifies processing by allowing you to use roughly equal exposure times for the Red, Green, and Blue filters, resulting in a more natural color image with less correction needed.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is the 1\/4 wavefront accuracy important for the ZWO Premium LRGB filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA \u003cstrong\u003e1\/4 wavefront\u003c\/strong\u003e specification means the filter's surface is extremely flat and will not distort the light passing through it. This preserves the native optical quality of your telescope, ensuring that stars remain as sharp and point-like as possible. Lower quality filters can introduce optical errors, softening the final image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo the ZWO Premium LRGB filters work well with cameras other than the ASI1600?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. While they were originally optimized for the popular ZWO ASI1600MM, their transmission curves, 1:1:1 color balance, and IR-cut features are beneficial for nearly any modern monochrome astronomy camera. They are an excellent match for sensors from Sony, Gpixel, and others.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the IR-cut feature on this ZWO LRGB filter set help my images?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eMonochrome sensors are sensitive to infrared (IR) light, which focuses at a different point than visible light. Unfiltered IR causes bloated, soft-looking stars and reduces overall image contrast. The sharp \u003cstrong\u003e700-1100nm\u003c\/strong\u003e IR cut-off on these filters completely blocks this unwanted light, leading to tighter stars and more accurate color data.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will this ZWO LRGB filter set perform on the Andromeda Galaxy (M31) from a suburban location?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis set is well-suited for imaging M31 from suburban skies. The Luminance filter will capture fine detail in the dust lanes with high transmission, while the RGB filters will gather color from the core and star-forming regions. The small spectral gaps between the filter passbands help to reject common light pollution sources, increasing the contrast between the galaxy and the skyglow.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the 1.25\" ZWO LRGB filters cause vignetting on my full-frame camera and f\/5 refractor?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, significant vignetting is likely in that scenario. 1.25\" filters are best suited for Four Thirds or smaller sensors; on APS-C sensors they will vignette, so 36mm or 2\" filters are needed there. For a full-frame sensor, especially in a fast f\/5 optical system, 2\" threaded filters are strongly recommended to ensure the entire sensor is illuminated.\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-LRGB125NEW\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eLRGB Filter Set\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\u003eFormat\u003c\/td\u003e\n\u003ctd\u003eThreaded, Round\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAccessory Type\u003c\/td\u003e\n\u003ctd\u003eFilter Set\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWarranty\u003c\/td\u003e\n\u003ctd\u003eZWO 2-Year Warranty\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\" Luminance (UV-IR) 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\" Red 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\" Green 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\" Blue 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":44967440744733,"sku":"ZWO-LRGB1.25NEW","price":207.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":44967440810269,"sku":"ZWO-LRGB2","price":419.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967440875805,"sku":"ZWO-LRGB36","price":279.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/ZWO-LRGB-Filters-Optimized-1-25-inch__12893.1596923433.1280.1280.jpg?v=1684341994"},{"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\u003eAbout 90% light transmission at the emission line\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 about 90% 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 90% 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 of about 90% 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\u003eSignal:\u003c\/strong\u003e Both bandpasses pass nearly all of the target emission line; the extra light a 7nm filter admits is mostly sky background, so 3nm filters give better contrast under light pollution.\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 pass nearly the same emission-line signal as 3nm filters; the extra light they admit is mostly sky background. They are \u003cstrong\u003emore forgiving\u003c\/strong\u003e on fast optical systems and 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\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003ePlastic Storage Box\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"}],"url":"https:\/\/davidastro.com\/en-us\/collections\/imaging-filters.oembed?page=5","provider":"David Astro","version":"1.0","type":"link"}