{"title":"Optolong","description":"\u003cdiv\u003e\n  \u003cp\u003e\n    Optolong's dual and multi-band filters changed what is possible with a one-shot colour camera under city skies. By passing hydrogen-alpha and oxygen III together and rejecting nearly everything between, they let a colour sensor capture narrowband-like contrast in a single session — no filter wheel, no monochrome workflow, no three-times-longer imaging. David Astro carries Optolong products in Canada, stocked domestically and ready to ship.\n  \u003c\/p\u003e\n  \u003cp\u003e\n    Which filter suits you depends on your camera type, focal ratio and target. Tell us all three and we will recommend.\n  \u003c\/p\u003e\n\u003c\/div\u003e\n\u003c!-- more --\u003e\n\u003cdiv\u003e\n  \u003ch2\u003eThe Optolong Filter Range\u003c\/h2\u003e\n  \u003cp\u003e\n    The line spans broadband light pollution rejection through single-line narrowband, with the dual and triple-band filters being the most widely used.\n  \u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eDual-band filters:\u003c\/strong\u003e Pass Ha and OIII together, which a colour camera's Bayer array separates naturally. The most effective single filter for one-shot colour imaging under light pollution.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eNarrower dual-band options:\u003c\/strong\u003e Tighter passbands giving higher contrast, best suited to slower focal ratios where the passband does not shift significantly.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eBroadband light pollution filters:\u003c\/strong\u003e Reject artificial emission lines while passing most of the spectrum, useful for galaxies and star clusters where narrowband would remove the target's own light.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSingle-line narrowband:\u003c\/strong\u003e Ha, OIII and SII in several bandwidths for monochrome imaging with a filter wheel.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eLRGB sets:\u003c\/strong\u003e Balanced colour separation filters with UV and IR blocking for monochrome broadband imaging.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSizes and formats:\u003c\/strong\u003e Mounted 1.25 inch and 2 inch, plus 31 mm, 36 mm and unmounted formats for filter wheels and drawers.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n  \u003ch2\u003eWhy Choose David Astro for Optolong\u003c\/h2\u003e\n  \u003cp\u003e\n    Dual-band filters are the highest-value purchase available to a colour imager in a city, provided the bandwidth suits the optics.\n  \u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFocal ratio matched:\u003c\/strong\u003e Very narrow dual-band filters lose performance below roughly f\/4 as the passband shifts. We recommend a bandwidth appropriate to your system.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCamera type considered:\u003c\/strong\u003e We distinguish clearly between what suits a one-shot colour camera and what suits monochrome, since the right filter differs completely.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSpacing accounted for:\u003c\/strong\u003e Filter thickness shifts focus, and we include it in the back-focus calculation supplied with your order.\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\u003eOptolong in Canada — Frequently Asked Questions\u003c\/h2\u003e\n  \u003cdl\u003e\n    \u003cdt\u003e\u003cstrong\u003eWhich filter for a colour camera in a city?\u003c\/strong\u003e\u003c\/dt\u003e\n    \u003cdd\u003eA dual-band Ha and OIII filter, almost without exception. It gives the largest single improvement available to a one-shot colour imager under light pollution, on emission nebulae.\u003c\/dd\u003e\n    \u003cdt\u003e\u003cstrong\u003eWill a dual-band filter help with galaxies?\u003c\/strong\u003e\u003c\/dt\u003e\n    \u003cdd\u003eNo. Galaxies emit across the spectrum, so a narrow filter removes their light along with the skyglow. Use a broadband light pollution filter, or better, a darker site.\u003c\/dd\u003e\n    \u003cdt\u003e\u003cstrong\u003eDoes bandwidth matter for my telescope?\u003c\/strong\u003e\u003c\/dt\u003e\n    \u003cdd\u003eYes below about f\/4, where a steep light cone shifts a narrow passband away from the emission line. In that case a slightly wider version performs better despite the looser rejection.\u003c\/dd\u003e\n    \u003cdt\u003e\u003cstrong\u003eCan I use these with a monochrome camera?\u003c\/strong\u003e\u003c\/dt\u003e\n    \u003cdd\u003eDual-band filters are designed for colour sensors. With monochrome, use single-line filters in a wheel, which gives better control and higher signal per channel.\u003c\/dd\u003e\n  \u003c\/dl\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n  \u003ch2\u003eImaging in colour from a bright site?\u003c\/h2\u003e\n  \u003cp\u003eTell us your camera and focal ratio and we will recommend the right filter. In Canadian stock, shipped worldwide.\u003c\/p\u003e\n\u003c\/div\u003e","products":[{"product_id":"optolong-l-pro-filter","title":"Optolong L-Pro Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eMulti-Bandpass Light Pollution Suppression\u003c\/li\u003e\n\u003cli\u003eEffective Spectrum from 380-750nm\u003c\/li\u003e\n\u003cli\u003eMaintains Natural Color Balance on Broadband Targets\u003c\/li\u003e\n\u003cli\u003eHigh Transmission on Major Nebula Emission Lines\u003c\/li\u003e\n\u003cli\u003eDurable Ion-Assisted Multi-Layer Coatings\u003c\/li\u003e\n\u003cli\u003eSurface Quality of 60\/40 per MIL-O-13830\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\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong L-Pro Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong L-Pro Filter is engineered to reclaim the night sky from urban light pollution, operating across a 380-750nm spectrum and manufactured to a 60\/40 surface quality standard. Its multi-bandpass design selectively blocks the most common wavelengths of artificial light while transmitting the light from deep-sky objects, resulting in images with dramatically improved contrast and natural color rendition.\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\u003eSuppressing Light Pollution Across the 380-750nm Spectrum\u003c\/h3\u003e\n\u003cp\u003eThe core function of the L-Pro is to isolate and reject specific emission lines from artificial light sources. It effectively targets the dominant wavelengths produced by mercury vapor, high-pressure sodium, and low-pressure sodium streetlights, which are the primary contributors to skyglow. By filtering these specific pollutants within its 380-750nm operational range, the L-Pro darkens the sky background without altering the light from your astronomical target.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eA Multi-Bandpass Design for Natural-Color Imaging\u003c\/h3\u003e\n\u003cp\u003eUnlike more aggressive filters that can produce a strong color cast, the L-Pro uses a balanced, multi-bandpass approach. This design preserves the natural colors of broadband targets like galaxies, reflection nebulae, and globular clusters. For imagers, this means less time spent on color correction in post-processing and a final result that more accurately represents the true colors of the object.\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 Transmission for Key H-Alpha and OIII Emission Lines\u003c\/h3\u003e\n\u003cp\u003eWhile excelling at broadband targets, the L-Pro also maintains high transmission for the most important emission nebula wavelengths. It passes critical lines including Hydrogen-alpha, Oxygen-III, Sulfur-II, and Hydrogen-beta. This allows you to capture the faint, glowing structures within objects like the Orion Nebula (M42) or the North American Nebula (NGC 7000) with enhanced contrast against the newly darkened 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\u003eBuilt to a 60\/40 Military Surface Quality Standard\u003c\/h3\u003e\n\u003cp\u003eEach L-Pro filter is manufactured to a 60\/40 surface quality specification according to military standard MIL-O-13830, ensuring clear, artifact-free images. The glass undergoes an ion-assisted deposition coating process, which creates a durable, scratch-resistant surface. This advanced coating technology also ensures the filter's central wavelength remains stable, preventing passband shifts due to temperature changes during an imaging session.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOptolong L-Pro vs. UHC Filters: Choosing the Right Tool\u003c\/h3\u003e\n\u003cp\u003eA common question is how the L-Pro compares to an Ultra High Contrast (UHC) filter. A UHC filter offers a more aggressive approach, providing maximum contrast on emission and planetary nebulae by isolating just the OIII and H-beta lines. This comes at the cost of nearly all star color and renders it ineffective for broadband targets.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eChoose a UHC Filter\u003c\/strong\u003e for visual observing or imaging of emission nebulae from heavily light-polluted areas where maximizing contrast is the only goal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eChoose the Optolong L-Pro\u003c\/strong\u003e when your targets include galaxies, reflection nebulae, or star clusters, or when preserving natural color is a priority. It is the more versatile, \"do-it-all\" light pollution filter for modern color cameras.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat makes the Optolong L-Pro different from other light pollution filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Optolong L-Pro is a \u003cstrong\u003emulti-bandpass filter\u003c\/strong\u003e designed for maximum color fidelity. Unlike narrowband or aggressive UHC filters that eliminate most star color, the L-Pro selectively blocks only the primary wavelengths of artificial light, preserving the natural color of broadband targets like galaxies and star clusters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong L-Pro filter suitable for visual use?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the L-Pro is effective for both visual observation and astrophotography. Visually, it darkens the sky background, making it easier to detect faint deep-sky objects from suburban locations. The improved contrast helps reveal subtle details in galaxies and nebulae that would otherwise be lost to skyglow.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Optolong L-Pro filter affect my images of the Andromeda Galaxy (M31) from a suburban backyard?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Andromeda Galaxy is a perfect target for the L-Pro. The filter will significantly increase the contrast between M31's faint outer arms and the brightened suburban sky. Crucially, it will do so while preserving the natural blue and yellow hues of the galaxy's star populations, providing a much more detailed and aesthetically pleasing image than you could capture without a filter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong L-Pro to image emission nebulae like the Orion Nebula (M42)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. The L-Pro allows high transmission of the key emission lines that make up the Orion Nebula, including Hydrogen-alpha and Oxygen-III. It will suppress local light pollution, increasing the contrast and revealing fainter details in the nebula's structure while retaining natural star colors in the Trapezium cluster and surrounding field.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the Optolong L-Pro filter block infrared (IR) light?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the L-Pro filter effectively blocks infrared wavelengths. This is a key feature for astrophotography, as it means you can use it as your primary luminance (\"L\") filter with a monochrome CCD or CMOS camera without needing a separate IR-cut filter, which simplifies your imaging train.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo I need a different Optolong L-Pro filter for my DSLR and my telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt depends on how you want to use it. The Optolong L-Pro is available in multiple formats to suit different setups:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25\" and 2\" Mounted:\u003c\/strong\u003e These thread directly into standard telescope eyepieces or camera nosepieces.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eClip-in Filters:\u003c\/strong\u003e These are designed for specific DSLR and mirrorless camera bodies (Canon, Nikon, Sony) and fit inside the camera, allowing you to use any camera lens.\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\u003eSpectrum\u003c\/td\u003e\n\u003ctd\u003e380-750nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40 (Refer to MIL-O-13830)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Options\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, Clip for Canon EOS APS-C, Clip for Canon EOS Full Frame, Clip for Nikon Full Frame, Clip for Sony Full Frame, Clip for Canon EOS-R\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Function\u003c\/td\u003e\n\u003ctd\u003eMulti-Bandpass Light Pollution Suppression\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating Technology\u003c\/td\u003e\n\u003ctd\u003eIon-Assisted Multi-Layer Coatings\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eOptolong L-Pro Filter (in selected format)\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 Storage 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\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":44967780811037,"sku":"OPT-10201","price":199.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":44967780843805,"sku":"OPT-10202","price":279.0,"currency_code":"CAD","in_stock":true},{"title":"Clip for Canon EOS APS-C","offer_id":44967780909341,"sku":"OPT-10203","price":349.0,"currency_code":"CAD","in_stock":true},{"title":"Clip for Canon EOS Full Frame","offer_id":44967780942109,"sku":"OPT-LPRO-EOS-FF","price":377.0,"currency_code":"CAD","in_stock":true},{"title":"Clip for Nikon Full Frame","offer_id":44967780974877,"sku":"OPT-LPRO-NIKON-FF","price":377.0,"currency_code":"CAD","in_stock":true},{"title":"Clip for Sony Full Frame","offer_id":44967781007645,"sku":"OPT-10208","price":377.0,"currency_code":"CAD","in_stock":true},{"title":"Clip for Canon EOS-R","offer_id":44967781040413,"sku":"OPT-10211","price":349.0,"currency_code":"CAD","in_stock":true},{"title":"Clip for Nikon Z Full Frame","offer_id":52942348484893,"sku":"OPT-LPRO-NK-Z","price":349.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Optolong-L-Pro-2inch__58386.1612893783.1280.1280.jpg?v=1684345839"},{"product_id":"optolong-l-enhance-filter","title":"Optolong L-Enhance Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDual-bandpass filter isolates H-Alpha, H-Beta, and OIII emission lines\u003c\/li\u003e\n\u003cli\u003ePeak transmission of over 90% for maximum signal\u003c\/li\u003e\n\u003cli\u003eBlocks over 99% of light pollution across a 300-1000nm range\u003c\/li\u003e\n\u003cli\u003eMaintains image sharpness with a λ\/4 transmitted wavefront\u003c\/li\u003e\n\u003cli\u003eConstructed from 1.85mm thick B270 optical glass\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong L-Enhance Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong L-Enhance filter is an economical, high-transmission solution for color astrophotography from light-polluted skies. This dual-bandpass filter achieves over 90% peak transmission in the critical H-Alpha, H-Beta, and Oxygen III emission lines, capturing the most important nebula data with any color camera. It simultaneously eliminates the impact of urban skyglow by blocking more than 99% of light pollution lines across a wide 300-1000nm range. The entire optical path is built on a 1.85mm B270 substrate polished to a λ\/4 transmitted wavefront, ensuring your telescope's resolution is perfectly preserved.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eDual-Bandpass Design: Over 90% Transmission in H-Alpha, H-Beta \u0026amp; OIII\u003c\/h3\u003e\n\u003cp\u003eUnlike broadband filters that pass large sections of the spectrum, the L-Enhance isolates only the most important wavelengths for emission nebulae. By targeting H-Alpha (656nm), H-Beta (486nm), and OIII (500nm) with a peak transmission greater than 90%, it dramatically increases the contrast between your target and the sky background. This design choice prioritizes the wavelengths associated with hydrogen and oxygen—the building blocks of star formation—to deliver scientifically significant data from your color camera in a single shot.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eLight Pollution Suppression: \u0026gt;99% Rejection of Unwanted City Glow\u003c\/h3\u003e\n\u003cp\u003eFor imagers in urban or suburban locations, the primary challenge is skyglow from artificial lighting. The L-Enhance filter meets this challenge with an aggressive blocking depth of over 99% for major light pollution sources, including mercury and sodium vapor lamps. This deep blocking darkens the sky background in your images, allowing the faint, desirable light from nebulae to stand out clearly. The result is longer possible sub-exposure times and a signal-to-noise ratio that was previously only achievable from dark sites.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOptical \u0026amp; Build Quality: λ\/4 Wavefront on a 1.85mm B270 Substrate\u003c\/h3\u003e\n\u003cp\u003eA filter should only transmit light, not distort it. The Optolong L-Enhance is built on a 1.85mm thick B270 glass substrate, polished to a surface quality of 60\/40 and a parallelism of 30 arcseconds. Critically, it guarantees a transmitted wavefront of λ\/4 or better, ensuring that it will not introduce aberrations or degrade the sharp stars produced by your telescope's optics. Advanced ion-assisted deposition coatings ensure these transmission characteristics are durable, scratch-resistant, and stable regardless of temperature changes during an imaging session.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe 1-Shot-Color Solution: L-Enhance vs. Monochrome Narrowband\u003c\/h3\u003e\n\u003cp\u003eWhile a monochrome camera with a filter wheel and separate S-II, H-Alpha, and O-III filters offers maximum data control, this approach is complex and expensive. The Optolong L-Enhance provides a streamlined and highly effective alternative for one-shot-color (OSC) cameras like DSLRs and dedicated astronomy CMOS cameras.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eEfficiency:\u003c\/strong\u003e The L-Enhance captures two of the most important bandpasses (H-Alpha and OIII) simultaneously, dramatically reducing the total imaging time required compared to shooting each channel separately with a mono camera.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSimplicity:\u003c\/strong\u003e It eliminates the need for a filter wheel and the complexities of combining multiple monochrome datasets, making deep-sky imaging more accessible.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCost-Effectiveness:\u003c\/strong\u003e For a fraction of the cost of a full monochrome setup, the L-Enhance unlocks the ability to shoot high-contrast nebula images from the city.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat makes the Optolong L-Enhance different from a standard light pollution filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA standard light pollution (LPS) filter is a \u003cstrong\u003ebroadband\u003c\/strong\u003e filter that tries to notch out specific light pollution lines while passing most other light. The Optolong L-Enhance is a \u003cstrong\u003emulti-bandpass narrowband\u003c\/strong\u003e filter. It works in reverse: it blocks almost the entire spectrum, only passing specific, narrow bands corresponding to nebula emission lines (H-Alpha, H-Beta, and OIII), resulting in much higher contrast.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong L-Enhance filter with a monochrome camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, you can. While designed for color cameras, the L-Enhance works well with a monochrome camera to capture H-Alpha, H-Beta, and OIII data simultaneously for a high-quality luminance frame. This is useful for simplifying data acquisition, though you will not be able to separate the individual channels for color mapping as you would with dedicated single-bandpass filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong L-Enhance perform on a target like the North America Nebula (NGC 7000) from the suburbs?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Optolong L-Enhance is exceptionally effective on emission nebulae like the North America Nebula (NGC 7000) and the nearby Pelican Nebula (IC 5070). These targets are rich in Hydrogen-Alpha, which the filter passes with over 90% transmission. From a suburban location, the filter's \u0026gt;99% blocking of skyglow will darken the background, revealing the intricate structures and faint extensions of the nebula that would otherwise be lost.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong L-Enhance effective for imaging the Veil Nebula complex under moonlight?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. Moonlight is broadband light, and a narrowband filter like the L-Enhance is the best tool for mitigating its effects. Because the filter only passes the narrow bands of OIII and H-Alpha\/H-Beta, it blocks the vast majority of moonlight. This allows you to continue imaging targets rich in those emissions, like the Veil Nebula, even during bright moonlit nights.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy does the Optolong L-Enhance pass H-Beta in addition to H-Alpha and OIII?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe H-Beta emission line (486nm) is very close to the OIII lines (~500nm). The L-Enhance is designed with a wider bandpass in the blue-green part of the spectrum that includes both OIII and H-Beta. This captures more signal from objects that have strong H-Beta emission, such as the California Nebula or Horsehead Nebula, adding to the richness of the final image from a color camera.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill I need to refocus when using the 1.85mm Optolong L-Enhance filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, adding any filter into the optical path will shift the focus point. The 1.85mm thickness of the B270 glass will require a small amount of outward focus travel. It is always recommended to check and readjust focus after inserting or removing a filter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Material\u003c\/td\u003e\n\u003ctd\u003eB270\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Thickness\u003c\/td\u003e\n\u003ctd\u003e1.85mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePeak Transmission\u003c\/td\u003e\n\u003ctd\u003eT\u0026gt;90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Range\u003c\/td\u003e\n\u003ctd\u003e300-1000nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Depth\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;99% at light pollution lines\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront\u003c\/td\u003e\n\u003ctd\u003eλ\/4 RMS\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30s\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, Clip for Canon EOS APS-C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":44967781531933,"sku":"OPT-13801","price":251.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":44967781564701,"sku":"OPT-13802","price":321.0,"currency_code":"CAD","in_stock":true},{"title":"Clip for Canon EOS APS-C","offer_id":44967781597469,"sku":"OPT-13804","price":363.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Optolong-L-Enhance-2inch__85261.1612894707.1280.1280.jpg?v=1684345842"},{"product_id":"optolong-uhc-filter","title":"Optolong UHC Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eReduces skyglow from artificial and natural light pollution\u003c\/li\u003e\n\u003cli\u003eBlocks \u0026gt;99% of mercury vapor and sodium vapor light\u003c\/li\u003e\n\u003cli\u003ePasses key nebula emission lines including H-Alpha, H-Beta, and OIII\u003c\/li\u003e\n\u003cli\u003eTransmitted Wavefront RMS of ¼ λ\u003c\/li\u003e\n\u003cli\u003eAvailable in 1.25\" and 2\" mounted sizes, plus DSLR clip-in formats\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong UHC Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong UHC (Ultra High Contrast) Filter is engineered to reclaim night sky views from light-polluted areas, delivering \u0026gt;99% blocking of artificial light sources across a 300-700nm range. By isolating critical nebula emission lines with a precision ¼ λ transmitted wavefront, it dramatically increases the contrast between your target and a brightened sky background. The entire optical system maintains 30s parallelism, ensuring the enhanced view is not distorted.\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 Suppression: \u0026gt;99% Light Pollution Blocking at OD3\u003c\/h3\u003e\n\u003cp\u003eThe UHC filter aggressively targets the most common sources of urban skyglow. It achieves an optical density of OD3, blocking more than 99% of light from mercury vapor lamps, high and low-pressure sodium vapor lights, and the natural skyglow caused by neutral oxygen emission. This selective blocking darkens the sky background significantly, making faint nebula structures visible where they would otherwise be lost in the glare.\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\u003eTargeted Transmission: High Contrast on OIII, H-Beta, and H-Alpha Nebulae\u003c\/h3\u003e\n\u003cp\u003eWhile blocking unwanted light, the Optolong UHC filter maintains high transmission for the most important deep-sky wavelengths. It passes the light from emission nebulae at OIII (496nm, 500nm), H-Beta (486nm), and H-Alpha (656nm). This makes it exceptionally effective on targets like the Orion Nebula (M42) and the Lagoon Nebula (M8), revealing intricate detail and structure by separating the nebula's light from the washed-out 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\u003eOptical Precision: ¼ λ Wavefront and 60\/40 Surface Quality\u003c\/h3\u003e\n\u003cp\u003eA filter is only as good as the image it passes. The Optolong UHC is built on an optical glass substrate polished to a surface quality of 60\/40 and a transmitted wavefront of ¼ λ or better. Ion-assisted deposition coatings ensure durability and resistance to scratching, while a 30s parallelism guarantees that you are not introducing optical errors into your imaging or visual train. This preserves the sharpness and resolution of your telescope.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOptolong UHC vs. CLS: Choosing the Right Filter for Your Sky\u003c\/h3\u003e\n\u003cp\u003eThe Optolong UHC has a narrower bandpass compared to a City Light Suppression (CLS) filter, giving it higher contrast. This makes the UHC a better choice for observers in more heavily light-polluted urban and suburban environments. A CLS filter provides a more natural color balance and works well in darker locations, while the UHC excels at digging faint emission nebulae out of the most challenging skyglow.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eUHC Filter:\u003c\/strong\u003e Best for severe light pollution, maximizing contrast on emission nebulae.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCLS Filter:\u003c\/strong\u003e Better for mild light pollution or dark sites, offering a broader passband and more natural star colors.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main difference between the Optolong UHC filter and a CLS filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary difference is the width of the passband. The \u003cstrong\u003eOptolong UHC (Ultra High Contrast) filter\u003c\/strong\u003e has a narrower passband, providing more aggressive light pollution rejection and higher contrast on emission nebulae. A CLS (City Light Suppression) filter has a broader passband, resulting in more natural star colors but less intense contrast, making it better suited for moderately light-polluted skies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Optolong UHC filter improve my view of the Orion Nebula (M42) from a city?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFrom a city, the Orion Nebula (M42) often appears as a small, bright core with its fainter outer structures washed out by skyglow. The Optolong UHC filter blocks this skyglow while passing the nebula's own H-Alpha, H-Beta, and OIII light. This darkens the background sky, dramatically increasing contrast and allowing you to see the faint, extended wings and intricate dust lanes of the nebula that were previously invisible.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong UHC filter suitable for astrophotography with a color camera or DSLR?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the Optolong UHC filter is designed for both visual use and astrophotography with color cameras, including unmodified DSLRs and dedicated one-shot-color astronomy cameras. Its substantial red passband allows it to capture critical H-Alpha data, which is often weak in other light pollution filters, leading to more balanced and detailed nebula images from the city.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the Optolong UHC filter make galaxies and star clusters brighter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo. The Optolong UHC filter works by selectively blocking light, which means it will dim all objects to some degree. It is designed for \u003cstrong\u003eemission nebulae\u003c\/strong\u003e, which emit light at specific wavelengths the filter passes. Broadband targets like \u003cstrong\u003egalaxies, reflection nebulae, and star clusters\u003c\/strong\u003e emit light across the entire spectrum. The filter will block much of their light, making them appear dimmer and often harder to see. For these objects, it's best to observe from a dark site without a filter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong UHC filter for visual observing with my 8\" Dobsonian?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. An 8\" Dobsonian is an excellent instrument for visual deep-sky observing, and the Optolong UHC filter is a perfect accessory for it, especially from suburban skies. It will significantly enhance views of emission nebulae like the Swan Nebula (M17) and the Veil Nebula (NGC 6960), making them stand out clearly against a darkened sky background.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is the Optolong UHC filter not recommended for solar observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eWARNING: NEVER use this filter for solar observation.\u003c\/strong\u003e The Optolong UHC filter is designed to block specific, narrow wavelengths of light from artificial sources at night. It does not block the intense, full-spectrum visible and invisible (infrared, ultraviolet) radiation from the Sun. Looking at the Sun with this filter, or any filter not explicitly designed for solar viewing, will cause immediate and permanent blindness.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eOptical glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Range\u003c\/td\u003e\n\u003ctd\u003e300-700nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Depth\u003c\/td\u003e\n\u003ctd\u003eOD3, light pollution line blocking \u0026gt;99%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40 (MIL-O-13830A)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront RMS\u003c\/td\u003e\n\u003ctd\u003e¼ λ\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30s\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Formats\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, Clip for Canon EOS APS-C, Clip for Canon EOS Full Frame, Clip for Nikon Full Frame\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":44967781695773,"sku":"OPT-10101","price":77.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":44967781728541,"sku":"OPT-10102","price":119.0,"currency_code":"CAD","in_stock":true},{"title":"Clip for Canon EOS APS-C","offer_id":44967781761309,"sku":"OPT-UHC-EOS-APSC","price":133.0,"currency_code":"CAD","in_stock":true},{"title":"Clip for Canon EOS Full Frame","offer_id":44967781794077,"sku":"OPT-UHC-EOS-FF","price":161.0,"currency_code":"CAD","in_stock":true},{"title":"Clip for Nikon Full Frame","offer_id":44967781826845,"sku":"OPT-UHC-NIKON-FF","price":161.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Optolong-UHC-2inch__75062.1612994619.1280.1280.jpg?v=1684345844"},{"product_id":"optolong-l-extreme-filter","title":"Optolong L-Extreme Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eNarrow dual-bandpass filter for H-Alpha and OIII\u003c\/li\u003e\n\u003cli\u003eBlocks \u0026gt;99% of light pollution emission lines\u003c\/li\u003e\n\u003cli\u003ePeak transmission of \u0026gt;90% at critical wavelengths\u003c\/li\u003e\n\u003cli\u003eTransmitted Wavefront RMS of λ\/4\u003c\/li\u003e\n\u003cli\u003e1.85mm thick B270 substrate with 30s parallelism\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong L-Extreme Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong L-Extreme Filter isolates critical nebula emission lines with over 90% peak transmission while blocking more than 99% of common light pollution sources. Built on a 1.85mm B270 substrate, its λ\/4 transmitted wavefront and 30s parallelism ensure your optical system's native resolution is maintained. This narrow dual-band design simultaneously captures H-alpha and Oxygen III, maximizing contrast for one-shot color and monochrome cameras operating under bright urban skies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eA Dual-Band Design for \u0026gt;99% Light Pollution Suppression\u003c\/h3\u003e\n\u003cp\u003eThe L-eXtreme isolates the two most important emission lines for most nebulae—Hydrogen-alpha and Oxygen III—on a single filter. By aggressively blocking wavelengths outside these passbands, including a \u0026gt;99% rejection of artificial light pollution, the filter produces a dramatic increase in contrast between your target and the skyglow background. This allows you to capture clean, detailed data even from severely light-polluted locations or during bright moonlit nights.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOptimized for Fast Optics and One-Shot Color Cameras\u003c\/h3\u003e\n\u003cp\u003eModern fast optical systems, such as f\/2 RASA or HyperStar setups, place high demands on filter performance. The L-eXtreme is engineered to minimize band-shift with these steep light cones, ensuring consistent transmission and color balance. For imagers using one-shot color cameras like DSLRs or dedicated CMOS astronomy cameras, this filter is a cost-effective and convenient way to produce detailed bicolor images without the need for a filter wheel and monochrome setup.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eλ\/4 Wavefront Accuracy and Durable Ion-Assisted Coatings\u003c\/h3\u003e\n\u003cp\u003eA filter should never degrade the quality of your telescope's optics. The L-eXtreme is manufactured to strict tolerances, with a transmitted wavefront of λ\/4 and parallelism of 30 arcseconds, preventing any introduction of aberrations or distorted star shapes. The multi-layer coatings are applied using an advanced ion-assisted deposition process, creating a durable, scratch-resistant surface that provides wavelength stability regardless of temperature changes during an imaging session.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOptolong L-eXtreme vs. L-eNhance: The Tri-Band Trade-Off\u003c\/h3\u003e\n\u003cp\u003eThe primary difference lies in their bandpass strategy. The L-eNhance is a tri-band filter, passing H-alpha, OIII, and H-beta. The L-eXtreme is a dual-band filter, passing only H-alpha and OIII.\u003c\/p\u003e\n\u003cp\u003eThe L-eXtreme's advantage is its complete rejection of the wavelengths between the H-beta and OIII lines. This region contains no significant nebula emission but is a source of urban light pollution. By blocking it, the L-eXtreme delivers a darker sky background and higher overall contrast on most targets, making it the superior choice for maximum signal-to-noise ratio in heavy light pollution.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat makes the Optolong L-eXtreme different from the L-eNhance filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003eOptolong L-eXtreme\u003c\/strong\u003e is a dual-band filter that isolates the H-alpha and OIII emission lines. The L-eNhance is a tri-band filter that also includes H-beta. The L-eXtreme provides higher contrast and darker skies by blocking the light pollution between the H-beta and OIII lines, a region with no major nebula emissions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong L-eXtreme filter with my DSLR camera in the city?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. The L-eXtreme is designed specifically for this purpose. It works exceptionally well with one-shot color cameras like DSLRs and dedicated astronomy cameras, allowing you to capture high-contrast images of emission nebulae despite heavy urban light pollution.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong L-eXtreme perform on the Orion Nebula (M42) from a light-polluted suburb?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe L-eXtreme is an excellent choice for the Orion Nebula (M42). It will dramatically darken the sky background, enhancing the faint, extended nebulosity while preserving the natural colors of the hydrogen (red) and oxygen (teal) regions. You will be able to capture significantly more detail in the nebula's structure than you could without a filter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong L-eXtreme suitable for fast telescopes like a RASA or HyperStar system?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the L-eXtreme is well-suited for fast optical systems. Its coatings are designed to minimize the band-shift effects that can occur with steep light cones (low f-ratios), ensuring reliable performance and color balance even at f\/2.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the L-eXtreme filter work for monochrome cameras?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile designed with one-shot color cameras in mind, the L-eXtreme can be used effectively with monochrome cameras. It allows you to capture H-alpha and OIII data simultaneously. For serious monochrome imaging, separate narrowband filters for Ha, OIII, and SII will offer more control, but the L-eXtreme provides a convenient way to gather data for a bicolor Hubble-palette style image in less time.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy doesn't the Optolong L-eXtreme pass H-beta light?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis is a deliberate design choice to maximize contrast. While a few nebulae, like the Horsehead Nebula (Barnard 33), have a notable H-beta signal, most emission nebulae are dominated by H-alpha and OIII. By blocking the H-beta line and the region between it and OIII, the L-eXtreme eliminates more light pollution, leading to a better signal-to-noise ratio on the vast majority of targets.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eB270\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eThickness\u003c\/td\u003e\n\u003ctd\u003e1.85mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePeak Transmission\u003c\/td\u003e\n\u003ctd\u003eT\u0026gt;90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Range\u003c\/td\u003e\n\u003ctd\u003e300-1000nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Depth\u003c\/td\u003e\n\u003ctd\u003eLight pollution line blocking \u0026gt;99%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront RMS\u003c\/td\u003e\n\u003ctd\u003eλ\/4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30s\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":44967910277405,"sku":"OPT-13901","price":335.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":44967910310173,"sku":"OPT-13902","price":432.0,"currency_code":"CAD","in_stock":true},{"title":"Clip for Nikon Z Full Frame","offer_id":52942348550429,"sku":"OPT-LEXTREME-NK-Z","price":363.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Optolong-L-Enhance__74495.1625788241.1280.1280.jpg?v=1684346873"},{"product_id":"optolong-lrgb-ha-oiii-sii-filter-set","title":"Optolong LRGB, Ha, OIII \u0026 SII Filter Set","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eComplete 7-filter set for monochrome astrophotography\u003c\/li\u003e\n\u003cli\u003eIncludes Luminance, Red, Green, and Blue broadband filters\u003c\/li\u003e\n\u003cli\u003eIncludes 3nm Hydrogen-alpha, Oxygen-III, and Sulphur-II narrowband filters\u003c\/li\u003e\n\u003cli\u003eLRGB set features a gap to block 589nm sodium light pollution\u003c\/li\u003e\n\u003cli\u003eEnables both natural color LRGB and Hubble Palette SHO imaging\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong LRGB, Ha, OIII \u0026amp; SII Filter Set\u003c\/h2\u003e\n\u003cp\u003eThe Optolong LRGB, Ha, OIII \u0026amp; SII Filter Set provides a complete 7-filter solution for advanced monochrome imaging. This comprehensive kit combines a high-contrast LRGB filter set for natural-color broadband targets with a trio of 3nm narrowband filters for isolating emission nebulae. The LRGB set is engineered with a specific gap between the green and red filters to block the primary sodium light pollution line at 589nm, while the 3nm SHO filters target the critical 656nm H-alpha and 500nm OIII emission lines for maximum signal and contrast.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eLRGB + 3nm SHO: The Complete 7-Filter Monochrome Solution\u003c\/h3\u003e\n\u003cp\u003eThis 7-filter set equips your monochrome camera for virtually any deep-sky object. You can capture galaxies and star clusters in true-to-life color with the LRGB filters, then switch to the 3nm narrowband filters to capture the faint, intricate structures of emission and planetary nebulae. By including both sets, Optolong eliminates the need to build a filter collection piece by piece, providing a unified system for both broadband and narrowband workflows.\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: Natural Color Balance with a 589nm Sodium Cutoff\u003c\/h3\u003e\n\u003cp\u003eThe Optolong LRGB filters are designed for maximum color separation and contrast. The transmission curves feature extremely high gradients to clearly differentiate color channels, while a carefully placed gap between the green and red filters blocks the prominent 589nm sodium light pollution line. This targeted rejection significantly improves color balance and makes post-processing more straightforward. Furthermore, OIII emission is allowed to pass through both the blue and green filters, ensuring high efficiency when capturing planetary nebulae in LRGB and preserving their natural teal coloration.\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\u003e3nm SHO Filters: Isolating Ha, OIII, and SII for the Hubble Palette\u003c\/h3\u003e\n\u003cp\u003eFor the highest possible contrast on emission nebulae, the 3nm SHO (Sulphur-II, Hydrogen-alpha, Oxygen-III) filters isolate the specific wavelengths of ionized gas while rejecting nearly all other light. This extreme narrow bandpass darkens the sky background, suppresses moonlight and artificial light pollution, and makes faint nebulosity stand out. By assigning the data from the SII, Ha, and OIII filters to the red, green, and blue channels in processing, you can create the iconic, high-contrast images made famous by the Hubble Space 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\u003e656nm Ha \u0026amp; 500nm OIII: Capturing the Universe's Primary Emission Lines\u003c\/h3\u003e\n\u003cp\u003eThe 3nm H-alpha filter is centered at 656nm, capturing the dominant wavelength emitted by vast star-forming regions across the Milky Way. The 3nm OIII filter is centered at 500nm to capture the strong blue-green light from doubly ionized oxygen, characteristic of planetary nebulae and supernova remnants. Used together, these two filters can produce stunning bicolor images that reveal incredible structural detail while maintaining a natural, scientifically relevant color palette.\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 this Optolong 7-filter set?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary advantage is its completeness. This single set provides all the necessary filters for the two main types of monochrome deep-sky imaging: \u003cstrong\u003eLRGB\u003c\/strong\u003e for broadband targets like galaxies and star clusters, and \u003cstrong\u003e3nm SHO narrowband\u003c\/strong\u003e for emission nebulae. This allows you to tackle any object without needing to purchase additional filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is the 3nm bandpass on the Optolong SHO filters important?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA 3nm bandpass is extremely narrow, meaning it only allows a tiny sliver of the light spectrum to pass through to the sensor. This provides exceptional rejection of light pollution from city lights, moonlight, and natural skyglow. The result is a much darker background and significantly higher contrast on faint nebulae compared to wider 6nm or 7nm filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow would I use this Optolong filter set to image the Orion Nebula (M42)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eM42 is a complex object with both bright stars and extensive nebulosity. A great approach is a hybrid one:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eUse the \u003cstrong\u003eH-alpha and OIII filters\u003c\/strong\u003e to capture long exposures of the faint, sprawling nebulosity with high contrast.\u003c\/li\u003e\n\u003cli\u003eUse the \u003cstrong\u003eLRGB filters\u003c\/strong\u003e to capture a series of shorter exposures to resolve the bright Trapezium star cluster at the core without overexposing it.\u003c\/li\u003e\n\u003cli\u003eIn post-processing, you can combine the data from all filters to create a final image with a full dynamic range and rich detail.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhich filters from the Optolong set are best for the Andromeda Galaxy (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Andromeda Galaxy is a broadband target, meaning it shines across the visible spectrum like a star cluster. For M31, you would primarily use the \u003cstrong\u003eLRGB filters\u003c\/strong\u003e to capture its bright core, spiral arms, and dust lanes in natural color. You can also use the \u003cstrong\u003eH-alpha filter\u003c\/strong\u003e to take very long exposures, which will reveal the small, pinkish star-forming regions (HII regions) embedded within its spiral arms.\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 does this Optolong set enable it?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Hubble Palette is a false-color imaging technique used to differentiate structures in emission nebulae. It involves mapping data from the three narrowband filters to the RGB channels of a color image:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSulphur-II (SII)\u003c\/strong\u003e data is mapped to the \u003cstrong\u003eRed\u003c\/strong\u003e channel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHydrogen-alpha (Ha)\u003c\/strong\u003e data is mapped to the \u003cstrong\u003eGreen\u003c\/strong\u003e channel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOxygen-III (OIII)\u003c\/strong\u003e data is mapped to the \u003cstrong\u003eBlue\u003c\/strong\u003e channel.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThis Optolong set includes all three required SII, Ha, and OIII filters, allowing you to create these vibrant and detailed images.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does the gap between the green and red Optolong LRGB filters do?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe gap is a design feature for light pollution suppression. It is specifically placed to block the transmission of light around the \u003cstrong\u003e589nm\u003c\/strong\u003e wavelength. This is the primary emission line of sodium-vapor streetlights, a major source of urban skyglow. By blocking this line, the filters improve color separation and produce a cleaner image from suburban or city locations.\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 Count\u003c\/td\u003e\n\u003ctd\u003e7 (Luminance, Red, Green, Blue, Ha, OIII, SII)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNarrowband Bandpass\u003c\/td\u003e\n\u003ctd\u003e3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-Alpha Center Wavelength\u003c\/td\u003e\n\u003ctd\u003e656nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOIII Center Wavelength\u003c\/td\u003e\n\u003ctd\u003e500nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLight Pollution Rejection\u003c\/td\u003e\n\u003ctd\u003eNotch at 589nm (Sodium Line)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Formats\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 36mm Round Unmounted, 2\" Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eLuminance (L) 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\"\u003eRed (R) 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\"\u003eGreen (G) 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\"\u003eBlue (B) 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\"\u003e3nm H-Alpha (Ha) 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\"\u003e3nm Oxygen-III (OIII) 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\"\u003e3nm Sulphur-II (SII) 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\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":44967911293213,"sku":"OPT-LRGBSHO-1.25","price":931.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967911358749,"sku":"OPT-LRGBSHO-RD36","price":1085.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":44967911391517,"sku":"OPT-LRGBSHO-2","price":1413.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Optolong-LRGB-Ha-OIII-SII-Filter-Set__74483.1626291721.1280.1280.jpg?v=1684346905"},{"product_id":"optolong-lrgb-filter-set","title":"Optolong LRGB Filter Set","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eComplete 4-filter LRGB set for monochrome cameras\u003c\/li\u003e\n\u003cli\u003eHigh average transmission of over 90% for maximum signal\u003c\/li\u003e\n\u003cli\u003eBlocks sodium light pollution at 589nm for improved color\u003c\/li\u003e\n\u003cli\u003eNear-parfocal 1.85mm substrate thickness minimizes refocusing\u003c\/li\u003e\n\u003cli\u003eλ\/4 transmitted wavefront ensures no degradation of optical 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\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong LRGB Filter Set\u003c\/h2\u003e\n\u003cp\u003eThe Optolong LRGB Filter Set is engineered for monochrome astrophotography, dividing the visual spectrum into four channels to build high-fidelity color images. With an average transmission over 90% and a precise 1.85mm substrate thickness, this set delivers maximum light-gathering efficiency while maintaining a near-parfocal focus across all four filters. The B270 glass substrate is polished to a λ\/4 transmitted wavefront and 30s parallelism, ensuring your telescope's resolution is perfectly preserved.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eLRGB Imaging: 4 Filters for Full-Color Monochrome Astrophotography\u003c\/h3\u003e\n\u003cp\u003eThis set enables you to leverage the high sensitivity of a monochrome sensor to create images with superior detail and color fidelity compared to one-shot-color cameras. The Luminance (L) filter captures fine detail across the visible spectrum, while the Red, Green, and Blue filters isolate their respective color channels. This method requires more acquisition and processing time but gives you complete control over color balance and noise reduction in post-processing. The OIII emission lines are strategically passed by both the Blue and Green filters, allowing for natural color rendition of planetary nebulae and supernova remnants.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWARNING:\u003c\/strong\u003e These filters are NOT for solar observation. Looking at the Sun with this product, even for a moment, will cause permanent and irreversible blindness.\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 90% Transmission with a 589nm Sodium Line Notch\u003c\/h3\u003e\n\u003cp\u003eEach filter in the Optolong LRGB set features advanced multi-layer coatings that achieve an average transmission of over 90%, maximizing the signal reaching your sensor. A key design feature is a deliberate gap between the passbands of the Green and Red filters, which effectively blocks the primary sodium light pollution line at 589nm. This targeted rejection enhances contrast and creates a cleaner separation between color channels, resulting in more natural colors straight from the camera, especially from suburban skies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e1.85mm Parfocal Design with λ\/4 Wavefront Accuracy\u003c\/h3\u003e\n\u003cp\u003eBuilt on a B270 glass substrate, all four filters share a tight thickness tolerance of 1.85mm, making them nearly parfocal. This minimizes the need to refocus when switching between filters, saving valuable imaging time and streamlining automated sequences. The optical surfaces are polished to a transmitted wavefront of λ\/4 and a parallelism of 30 arcseconds, guaranteeing that the filters will not introduce aberrations or degrade the sharpness of your telescope's optics.\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 using the Optolong LRGB Filter Set?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary advantage is leveraging a sensitive monochrome camera to produce images with higher resolution and better color control than typical one-shot-color cameras. By capturing separate Luminance, Red, Green, and Blue channels, you can optimize exposure for each, process them individually to reduce noise, and combine them for a final image with maximum detail and accurate color.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is there a gap between the green and red filters in the Optolong set?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis gap is a specific design choice to block artificial light pollution. It targets the prominent sodium vapor lamp emission line at \u003cstrong\u003e589nm\u003c\/strong\u003e. By blocking this wavelength, the Optolong LRGB filters reduce skyglow and improve the color balance and separation between the red and green channels for more natural-looking results.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eAre the Optolong LRGB filters parfocal?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThey are designed to be \u003cstrong\u003enearly parfocal\u003c\/strong\u003e. All filters in the set are made with a \u003cstrong\u003e1.85mm\u003c\/strong\u003e thick substrate, which minimizes the amount of focus shift required when changing from one filter to another. This is a significant benefit for automated imaging sessions, as it reduces the need for constant refocusing routines.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong LRGB set perform on a galaxy like Andromeda (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 galaxies from light-polluted areas. The Luminance filter will capture the faint outer arms and dust lanes with maximum detail, while the targeted blocking of sodium light pollution in the RGB filters helps increase contrast and improve color saturation. You can achieve a deep, detailed image of M31 with a more natural color balance than you could with an unfiltered camera.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong LRGB filters for imaging Jupiter with a monochrome camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this set is excellent for high-resolution planetary imaging. Using a monochrome camera with these filters allows you to capture extremely sharp detail in each color channel. The Red filter will emphasize features in Jupiter's belts, while the Blue filter can highlight details in the zones and the Great Red Spot. Combining the channels gives you a vibrant, detailed final image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs it safe to use the Optolong LRGB filters for viewing the Sun?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eABSOLUTELY NOT.\u003c\/strong\u003e These filters are designed for night-sky imaging and provide no protection from harmful solar radiation. Attempting to view or image the Sun with these filters will cause instant and permanent eye damage and will destroy your camera sensor. Only use certified solar filters designed specifically for observing the Sun.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Material\u003c\/td\u003e\n\u003ctd\u003eB270\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Thickness\u003c\/td\u003e\n\u003ctd\u003e1.85mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAverage Transmission\u003c\/td\u003e\n\u003ctd\u003eT\u0026gt;90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Range\u003c\/td\u003e\n\u003ctd\u003e350-1050nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLight Pollution Blocking\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;99%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront\u003c\/td\u003e\n\u003ctd\u003eλ\/4 RMS\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30 arcseconds\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 36mm Round Unmounted, 2\" Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":44967917781277,"sku":"OPT-LRGB-1.25","price":349.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967917846813,"sku":"OPT-LRGB-RD36","price":419.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":44967917879581,"sku":"OPT-LRGB-2","price":503.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Optolong-LRGB__36364.1632349103.1280.1280.jpg?v=1684347024"},{"product_id":"optolong-l-ultimate-filter","title":"Optolong L-Ultimate Ha\/OIII 3nm Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDual 3nm bandpass isolates Hydrogen-alpha and Oxygen-III emission lines\u003c\/li\u003e\n\u003cli\u003eBlocks light pollution across the 300-1000nm spectrum\u003c\/li\u003e\n\u003cli\u003eGreater than OD4 blocking of unwanted wavelengths\u003c\/li\u003e\n\u003cli\u003eλ\/4 transmitted wavefront for sharp, high-resolution images\u003c\/li\u003e\n\u003cli\u003ePrecision 60\/40 surface quality optical glass substrate\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong L-Ultimate Ha\/OIII 3nm Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong L-Ultimate Ha\/OIII 3nm Filter isolates critical nebula emission lines with an extremely narrow 3nm full width at half maximum (FWHM) for both its H-alpha and OIII channels. This filter achieves its deep-sky contrast by implementing greater than OD4 blocking across a wide 300-1000nm range, effectively eliminating light pollution from urban and suburban skies. Each filter is manufactured to a λ\/4 transmitted wavefront standard, ensuring that the filter itself does not degrade the resolution of your optical system.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eDual 3nm Bandpass for Maximum Nebula Contrast\u003c\/h3\u003e\n\u003cp\u003eBy restricting the incoming light to only the H-alpha (656nm) and OIII (500nm) emission lines within a tight 3nm window, the L-Ultimate filter dramatically increases the signal-to-noise ratio of emission nebulae. This surgical isolation means that the faint, intricate structures within targets like the Squid Nebula (OU4) or supernova remnants are captured with stark contrast against a near-black sky background. The result is an image with significantly more \"pop\" and detail compared to what is possible with broader-band filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e\u0026gt;OD4 Blocking for Urban Imaging\u003c\/h3\u003e\n\u003cp\u003eFor astrophotographers working under light-polluted skies, the L-Ultimate's primary function is its aggressive rejection of unwanted artificial and natural light. With a blocking efficiency rated at an optical density greater than 4 (\u0026gt;OD4), it effectively nullifies the glow from mercury vapor, high and low-pressure sodium streetlights, and the natural atmospheric airglow. This level of suppression allows you to capture clean, long-exposure data from even the most challenging urban environments, turning previously unfruitful nights into productive imaging sessions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eλ\/4 Optics and Advanced Ion Coatings\u003c\/h3\u003e\n\u003cp\u003eOptolong builds the L-Ultimate filter on an optical glass substrate polished to a 60\/40 surface quality and a transmitted wavefront of λ\/4, preserving the sharpness of your telescope's optics. The filter's dielectric coatings are applied using an advanced ion-assisted deposition process, which creates a durable, scratch-resistant surface. This modern coating technique also ensures the central wavelength of the bandpass remains stable and does not drift with temperature changes, providing consistent results from night to night.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eL-Ultimate vs. L-eXtreme \u0026amp; L-eNhance: Why 3nm Matters\u003c\/h3\u003e\n\u003cp\u003eWhile filters like the Optolong L-eXtreme and L-eNhance are effective dual-band filters, the L-Ultimate distinguishes itself with its much narrower 3nm bandpasses. This tighter specification provides several key advantages for specific imaging goals.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDarker Sky Background:\u003c\/strong\u003e The 3nm window passes less of the skyglow continuum and blocks more of the light from stars, leading to a darker overall background and enhanced nebula contrast.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBetter Star Suppression:\u003c\/strong\u003e By collecting less stellar light outside the core emission lines, stars appear smaller and less prominent, allowing the faint nebulosity to dominate the image.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTrade-Off:\u003c\/strong\u003e The primary limitation is that its tight bandpass is not well-suited for very fast optical systems (typically f\/4 and faster), where significant band-shift can occur. For these systems, a broader filter like the L-eXtreme may be more appropriate.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main difference between the Optolong L-Ultimate and the L-eXtreme filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary difference is the bandpass width. The \u003cstrong\u003eL-Ultimate uses a very narrow 3nm bandpass\u003c\/strong\u003e for both H-alpha and OIII, while the L-eXtreme uses a wider 7nm bandpass. The L-Ultimate's 3nm design provides a darker sky background and better star control, maximizing contrast on emission nebulae, but it is less suited for very fast telescopes.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong L-Ultimate filter with a DSLR or a color astronomy camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the L-Ultimate is specifically designed for use with one-shot color cameras like DSLRs and dedicated color CMOS\/CCD cameras. It passes both the red H-alpha and blue-green OIII light simultaneously, allowing you to capture a detailed, color-rich image of emission nebulae in a single set of exposures.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is the Optolong L-Ultimate not recommended for fast telescopes (f\/4 and faster)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eExtremely narrow filters like the L-Ultimate can experience \"band-shift\" when used with fast optical systems. The steep light cone from a fast telescope causes the filter's central wavelength to shift away from the intended emission line for off-axis light rays. This can result in a loss of signal. For telescopes f\/4 or faster, a filter with a slightly wider bandpass, like 7nm, is often a better choice to avoid this effect.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Optolong L-Ultimate perform on a target like the Veil Nebula (NGC 6960) from a city?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe L-Ultimate is ideal for this scenario. The Veil Nebula is rich in both H-alpha and OIII, and the filter's dual 3nm bandpasses will isolate this signal while its \u0026gt;OD4 blocking rejects the city light pollution. You can expect to capture the delicate, filamentary structure of the nebula with high contrast against a dark background, even from a heavily light-polluted site.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong L-Ultimate a good choice for my 8\" f\/10 SCT?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, an f\/10 Schmidt-Cassegrain Telescope is an excellent match for the L-Ultimate filter. Slower optical systems like SCTs do not cause the band-shift issues seen in fast refractors or Newtonians. The filter will work at its peak efficiency, delivering maximum contrast and light pollution suppression for imaging emission nebulae.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the Optolong L-Ultimate filter work on galaxies or reflection nebulae?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this filter is not designed for broadband targets. Galaxies like Andromeda (M31) and reflection nebulae like the Pleiades (M45) shine by reflecting starlight across the entire visible spectrum. The L-Ultimate blocks almost all of this light, so these objects would be rendered extremely faint or invisible. It is exclusively for emission nebulae that glow at the specific H-alpha and OIII wavelengths.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eFWHM\u003c\/td\u003e\n\u003ctd\u003eOIII 3nm, H-alpha 3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eOptical Glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Range\u003c\/td\u003e\n\u003ctd\u003e300-1000nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Efficiency\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;OD4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront RMS\u003c\/td\u003e\n\u003ctd\u003eλ\/4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30 arcseconds\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eOptolong L-Ultimate Ha\/OIII 3nm Filter with Protective Case\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":50286466203933,"sku":"OPT-11601","price":404.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":44968046559517,"sku":"OPT-11602","price":545.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Optolong-L-Ultimate-2-inch-2__17268.1665168471.1280.1280.jpg?v=1684348283"},{"product_id":"optolong-uv-ir-cut-filter","title":"Optolong UV\/IR Cut Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eBlocks Ultraviolet (UV) and Infrared (IR) wavelengths\u003c\/li\u003e\n\u003cli\u003eImproves image sharpness and reduces star bloat\u003c\/li\u003e\n\u003cli\u003eFunctions as a luminance (L) filter for monochrome cameras\u003c\/li\u003e\n\u003cli\u003eFeatures durable, scratch-resistant ion-assisted multi-coatings\u003c\/li\u003e\n\u003cli\u003eActs as a high-transmission dust shield for your camera sensor\u003c\/li\u003e\n\u003cli\u003eAvailable in 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\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\u003eOptolong UV\/IR Cut Filter\u003c\/h2\u003e\n      \u003cp\u003eThe Optolong UV\/IR Cut Filter is an essential tool for digital astrophotography, designed to restore image sharpness by blocking the invisible ultraviolet and infrared light that causes bloated stars and soft details. Because most telescope optics are corrected only for the visible spectrum, they bring UV and IR light to a different focal point, degrading contrast. This filter isolates the visible spectrum, ensuring your color or monochrome camera sensor captures a clean, sharp image from edge to edge.\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\u003eRestore Sharpness by Blocking Invisible Wavelengths\u003c\/h3\u003e\n      \u003cp\u003eUnfiltered CCD and CMOS sensors are highly sensitive to wavelengths outside human vision. This out-of-band signal reduces image quality, especially in refractive optics or camera lenses not designed for astronomical use. The Optolong UV\/IR Cut filter acts as a gatekeeper, transmitting the visible spectrum while rejecting the unfocused UV and IR light, resulting in tighter stars, higher contrast, and noticeably sharper details on planetary surfaces and in deep-sky objects.\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\u003eIon-Assisted Coatings for Consistent Results\u003c\/h3\u003e\n      \u003cp\u003eOptolong utilizes an advanced ion-assisted deposition process to create the multi-layer coatings on the UV\/IR Cut filter. This technology ensures the filter is highly resistant to scratching and easy to clean. The coatings are applied using a planetary rotation system, guaranteeing uniformity across the entire surface for consistent performance and a stable central wavelength that is unaffected by temperature changes during your imaging session.\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\u003eA Vital Luminance Filter and Sensor Dust Shield\u003c\/h3\u003e\n      \u003cp\u003eFor monochrome imagers, the UV\/IR Cut filter is the ideal luminance (L) filter for LRGB imaging, capturing fine detail with maximum visible-light transmission. For both color and mono cameras, it serves another critical function: acting as a high-quality dust shield. Placed in a filter wheel or drawer, it protects your sensor from dust settling during long exposures without altering color balance, keeping your optical train clean and your flat frames pristine.\u003c\/p\u003e\n      \u003cp\u003e\u003cstrong\u003eWARNING:\u003c\/strong\u003e This filter is NOT designed for solar observation. Do NOT look at or image the Sun with this filter. Permanent and irreversible eye damage will result. You will be blinded if you fail to observe this warning.\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 primary purpose of the Optolong UV\/IR Cut filter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eIts main purpose is to \u003cstrong\u003eblock ultraviolet (UV) and infrared (IR) light\u003c\/strong\u003e while transmitting visible light. Most telescopes focus visible light sharply, but UV and IR light focus at a different point, which can cause bloated stars and reduced image sharpness. This filter corrects that issue for any camera with a sensor sensitive to these wavelengths.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eDo I need the Optolong UV\/IR Cut filter for my modified DSLR or a dedicated astronomy camera?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003e\u003cstrong\u003eYes, absolutely.\u003c\/strong\u003e Modified DSLRs and nearly all dedicated color and monochrome astronomy cameras have their stock UV\/IR blocking filters removed to increase sensitivity, especially to Hydrogen-alpha light. Without a replacement UV\/IR Cut filter like this one, your images will suffer from star bloat and poor focus, especially when used with refractor telescopes or camera lenses.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Optolong UV\/IR Cut filter improve my views of Jupiter through an 8\" SCT?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eFor imaging, yes. When using a color or monochrome camera to capture video of Jupiter, the Optolong UV\/IR Cut filter will produce a \u003cstrong\u003esharper, higher-contrast image\u003c\/strong\u003e by eliminating the \"smear\" from unfocused IR light. For visual observation, its effect is typically not noticeable as the human eye is not sensitive to these wavelengths.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I use the Optolong UV\/IR Cut filter as a luminance filter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eWhen shooting with a monochrome camera and a filter wheel, the UV\/IR Cut filter serves as your \u003cstrong\u003eLuminance (\"L\") filter\u003c\/strong\u003e. You take long-exposure images through this filter to capture all the structural detail and brightness information in the visible spectrum. You then combine this sharp L-channel data with separate exposures taken through Red, Green, and Blue filters to create a final, full-color LRGB image.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWill this filter help reduce light pollution when imaging the Orion Nebula (M42)?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003e\u003cstrong\u003eNo.\u003c\/strong\u003e The Optolong UV\/IR Cut filter is not a light pollution filter. It is designed to pass the entire visible spectrum, including wavelengths from common sources of light pollution like streetlights. To combat light pollution, you would need a dedicated broadband filter (like a UHC) or a narrowband filter.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong UV\/IR Cut filter for observing the Sun?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003e\u003cstrong\u003eABSOLUTELY NOT.\u003c\/strong\u003e This filter provides no protection from the intense visible light and energy of the Sun. Attempting to view the Sun with this filter will cause immediate, catastrophic, and permanent blindness. Solar observation requires specialized solar filters designed for that express purpose that cover the front aperture of your telescope.\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\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eCoating Technology\u003c\/td\u003e\n\u003ctd\u003eIon-assisted deposition multi-coating\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003ePrimary Use\u003c\/td\u003e\n\u003ctd\u003eLuminance (L) filter, UV\/IR blocking\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eRecommended Cameras\u003c\/td\u003e\n\u003ctd\u003eMonochrome CCD\/CMOS, Color CCD\/CMOS, Modified DSLRs\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":44968071528733,"sku":"OPT-10601","price":62.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":44968071561501,"sku":"OPT-10602","price":91.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":52942348583197,"sku":"OPT-10604","price":77.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Optolong-UV-IR-Cut-2__28842.1673896686.1280.1280.jpg?v=1684348673"},{"product_id":"optolong-l-para-ha-oiii-10nm-filter-2","title":"Optolong L-Para HA\/OIII 10nm Filter - 2\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDual Narrowband H-Alpha \u0026amp; OIII Filter\u003c\/li\u003e\n\u003cli\u003eSuppresses Mercury, Sodium \u0026amp; LED Light Pollution\u003c\/li\u003e\n\u003cli\u003eOptimized for Fast-Ratio Systems (RASA, HyperStar)\u003c\/li\u003e\n\u003cli\u003eAdvanced Anti-Halo Optical Design\u003c\/li\u003e\n\u003cli\u003eDurable Ion-Assisted Deposition 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\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong L-Para HA\/OIII 10nm Filter - 2\"\u003c\/h2\u003e\n\u003cp\u003eThe Optolong L-Para HA\/OIII filter is a dual narrowband filter designed to isolate critical nebula emission lines from hydrogen-alpha and oxygen-III. It aggressively suppresses common sources of urban light pollution, including mercury-vapor, sodium, and LED streetlights. This targeted filtration darkens the sky background, significantly increasing the contrast of emission nebulae for more detailed and vibrant astrophotography.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eDual-Bandpass Design for High-Contrast Nebula Imaging\u003c\/h3\u003e\n\u003cp\u003eThe L-Para filter targets the two most prominent emission lines in most nebulae—Hydrogen-alpha and Oxygen-III. By selectively passing light from these wavelengths while rejecting the rest of the spectrum, it renders the sky background exceptionally dark. This approach dramatically enhances the contrast between your deep-sky target and the surrounding sky, revealing faint structures that would otherwise be lost to light pollution.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eUniversal Compatibility: Engineered for Fast and Standard Telescopes\u003c\/h3\u003e\n\u003cp\u003eA key design goal for the L-Para was compatibility across a wide range of instruments. It is engineered to maintain high transmission rates and color fidelity not only in standard focal ratio telescopes but also in very fast optical systems like RASA or HyperStar setups. The filter's performance holds up even when receiving steep, oblique light rays, ensuring one filter can serve your entire collection of telescopes without compromise.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eAdvanced Halo Suppression for Cleaner Stars\u003c\/h3\u003e\n\u003cp\u003eHalos around bright stars can obscure faint, nearby nebulosity and detract from the final image. The Optolong L-Para features an optimized coating stack specifically designed to minimize these artifacts. This meticulous anti-halo engineering results in cleaner, more precise star images and ensures that the delicate details of your target nebula remain the central focus.\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\u003eDurable Ion-Assisted Coatings for Lasting Reliability\u003c\/h3\u003e\n\u003cp\u003eOptolong utilizes an ion-assisted deposition coating process to produce the L-Para filter. This advanced technique creates a hard, dense coating that is highly resistant to scratching and environmental degradation. The result is a filter with stable, consistent wavelength transmission that will not deviate with temperature changes, providing reliable imaging results for years to come.\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 objects is the Optolong L-Para filter best for?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Optolong L-Para is specifically designed for imaging \u003cstrong\u003eemission nebulae\u003c\/strong\u003e, which are rich in Hydrogen-alpha and Oxygen-III light. It excels on targets like the Orion Nebula (M42), the Lagoon Nebula (M8), and the North American Nebula (NGC 7000).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong L-Para improve images from light-polluted skies?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt uses a dual narrowband design that selectively passes light from \u003cstrong\u003eHa and OIII\u003c\/strong\u003e while blocking broad-spectrum light from artificial sources like mercury, sodium, and LED streetlights. This darkens the sky background and dramatically boosts the contrast of your target.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Optolong L-Para work with my fast f\/2 RASA telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the L-Para is engineered for compatibility with a wide range of optical systems, including very fast focal ratios like those found on \u003cstrong\u003eRASA and HyperStar systems\u003c\/strong\u003e. It's designed to maintain high transmission and avoid band-shifting even with the steep light cones from these instruments.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong L-Para for imaging galaxies like Andromeda (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile you can, it's not ideal. The L-Para is a narrowband filter that blocks most of the light from \u003cstrong\u003ebroadband targets like galaxies\u003c\/strong\u003e, which emit light across the entire visible spectrum. For galaxies, a broadband light pollution filter or unfiltered imaging from a dark site is recommended.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat makes the Optolong L-Para's halo control notable?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eOptolong has specifically optimized the L-Para's coating design to \u003cstrong\u003esuppress halos\u003c\/strong\u003e, which are the rings of light that can appear around very bright stars. This results in cleaner star fields and prevents nebulosity near bright stars from being obscured.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong L-Para a good choice for a one-shot-color camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. Dual narrowband filters like the L-Para are an excellent match for \u003cstrong\u003eone-shot-color (OSC) cameras\u003c\/strong\u003e. They allow you to capture both Ha and OIII data simultaneously, simplifying your workflow and producing dramatic, high-contrast nebula images even from urban locations.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"Default Title","offer_id":50077460758813,"sku":"OPT-AS100221","price":362.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-L-Para-Filter.png?v=1750275530"},{"product_id":"optolong-l-quad-enhance-filter","title":"Optolong L-Quad Enhance Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eQuad-bandpass design for color cameras\u003c\/li\u003e\n\u003cli\u003eSuppresses light pollution with OD2-OD4 blocking depth\u003c\/li\u003e\n\u003cli\u003eMaintains sharpness with a λ\/4 transmitted wavefront\u003c\/li\u003e\n\u003cli\u003eConstructed from 1.85mm thick optical glass\u003c\/li\u003e\n\u003cli\u003eEnsures no double images with 30s parallelism\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong L-Quad Enhance Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong L-Quad Enhance Filter is a specialized quad-bandpass light pollution filter for one-shot-color cameras, built on a 1.85mm optical glass substrate. It delivers deep suppression of artificial and natural skyglow with an optical density of OD2-OD4 across a broad 300-1000nm blocking range, isolating key celestial emission lines while preserving broadband color. With a transmitted wavefront held to λ\/4 and parallelism of 30 arcseconds, the L-QEF maintains sharp, detailed star images across the entire field.\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\u003eQuad-Bandpass Light Pollution Suppression at OD2-OD4\u003c\/h3\u003e\n\u003cp\u003eDesigned specifically for color cameras, the L-Quad Enhance Filter utilizes four precisely defined bandpasses to combat light pollution. With a blocking depth of OD2 to OD4, it eliminates between 99% and 99.99% of unwanted wavelengths from sources like mercury and sodium streetlights, dramatically increasing the contrast between your target and the sky background. This aggressive suppression allows you to capture clean data even from suburban locations or under moonlight.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eλ\/4 Wavefront for Broadband Targets like Galaxies \u0026amp; Clusters\u003c\/h3\u003e\n\u003cp\u003eUnlike narrowband filters that isolate only emission lines, the L-QEF is engineered to capture both nebulae and broadband targets. Its passbands are chosen to preserve the continuous spectrum of galaxies and the subtle star colors in clusters, providing a more natural color balance directly out of the camera. The guaranteed λ\/4 transmitted wavefront ensures that the filter does not introduce optical errors, preserving the sharpness required to resolve fine details in targets like the Sculptor Galaxy (NGC 253) or the stars of the Double Cluster (NGC 869\/884).\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\u003e30s Parallelism for Pinpoint Stars Across the Field\u003c\/h3\u003e\n\u003cp\u003eOptical precision is critical in any filter, and the L-QEF is held to strict mechanical tolerances. A parallelism of 30 arcseconds guarantees that the two faces of the filter are almost perfectly parallel. This prevents the introduction of image shift or distorted stars, ensuring that pinpoint stellar images from your telescope's optics remain perfectly round and sharp from edge to edge.\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\u003eDurable Ion-Assisted Coatings on 1.85mm Substrate\u003c\/h3\u003e\n\u003cp\u003eThe L-Quad Enhance Filter's multi-layer coatings are applied using an advanced ion-assisted deposition process. This technology creates a dense, durable, and scratch-resistant surface that is easy to clean and maintains its spectral performance over time. Built on a 1.85mm thick optical glass substrate with a 60\/40 surface quality, the filter is parfocal with other standard astronomy filters, minimizing the need to refocus when using a filter wheel.\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 Optolong L-Quad Enhance Filter differ from a dual-band nebula filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA dual-band filter typically isolates only the H-alpha and OIII emission lines, which is ideal for emission nebulae but can result in unnatural colors for broadband targets like galaxies and star clusters. The \u003cstrong\u003eOptolong L-Quad Enhance Filter\u003c\/strong\u003e uses four passbands, which allows it to capture a more complete spectrum, resulting in better color balance for all types of deep-sky objects.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong L-Quad Enhance Filter to image the Sculptor Galaxy (NGC 253) from a suburban backyard?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this is an excellent use case for the \u003cstrong\u003eL-QEF\u003c\/strong\u003e. The filter is specifically designed to suppress common forms of light pollution while preserving the continuous spectrum of galaxies. It will help darken the sky background and increase the contrast of NGC 253's dust lanes and star-forming regions, making it possible to capture a high-quality image from light-polluted areas.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Optolong L-QEF perform on the North American Nebula (NGC 7000) with a one-shot-color camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003eL-QEF\u003c\/strong\u003e will perform very well. For large emission nebulae like the North American Nebula, the filter will isolate the critical red (H-alpha) and blue-green (H-beta\/OIII) wavelengths while blocking skyglow. This dramatically boosts the nebula's contrast against the background, revealing faint structures and details that would otherwise be lost.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the L-Quad Enhance Filter produce halos around bright stars?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003eOptolong L-Quad Enhance Filter\u003c\/strong\u003e is designed with advanced anti-reflection coatings to minimize halos and other internal reflections around bright stars. User tests confirm that it controls halos effectively, producing clean stellar profiles even on challenging targets.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does the λ\/4 wavefront specification mean for my images with the L-QEF?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA \u003cstrong\u003eλ\/4 (1\/4 wave) transmitted wavefront\u003c\/strong\u003e is a measure of optical flatness and precision. It guarantees that the filter will not degrade the quality of the light passing through it, preserving the sharpness and resolution delivered by your telescope. This is crucial for capturing fine details and maintaining tight, point-like stars.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong L-Quad Enhance Filter suitable for imaging under a full moon?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, while no filter can eliminate all moonlight, the \u003cstrong\u003eL-Quad Enhance Filter's\u003c\/strong\u003e strong suppression of background skyglow makes it highly effective at mitigating the impact of the Moon. It allows you to continue imaging on nights that would otherwise be unusable, significantly increasing your opportunities to capture data.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eOptical glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eThickness\u003c\/td\u003e\n\u003ctd\u003e1.85mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Range\u003c\/td\u003e\n\u003ctd\u003e300-1000nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Depth\u003c\/td\u003e\n\u003ctd\u003eOD2-OD4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront RMS\u003c\/td\u003e\n\u003ctd\u003eλ\/4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30s\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"2\" Mounted","offer_id":50289892688157,"sku":"OPT-14702","price":278.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-L-Quad-Enhance-Filter.jpg?v=1756170392"},{"product_id":"optolong-l1-dual-combo-set","title":"Optolong L-Quad Enhance + L-Para L1 Dual-Combo Filter Set - 2\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e\n\u003cstrong\u003eL-Quad Enhance Filter:\u003c\/strong\u003e A quad-bandpass filter designed for balanced RGB color from broadband targets.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eL-Para L1 Filter:\u003c\/strong\u003e A dual-narrowband filter that isolates H-alpha and OIII emission lines for high-contrast detail.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBroadband-Narrowband Synergy:\u003c\/strong\u003e A two-filter system designed for capturing separate color and detail data to be combined in post-processing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptimized for Fast Optics:\u003c\/strong\u003e The L-Para filter maintains excellent contrast and anti-halo characteristics even in fast optical systems.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIon-Assisted Coatings:\u003c\/strong\u003e Precision coatings ensure durability, scratch resistance, and stable central wavelength performance regardless of temperature changes.\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\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong L-Quad Enhance + L-Para L1 Dual-Combo Filter Set - 2\"\u003c\/h2\u003e\n\u003cp\u003eThe Optolong L-Quad Enhance and L-Para L1 Dual-Combo Filter Set redefines color astrophotography by separating the capture of broadband color and narrowband detail into two specialized steps. This \"Broadband-Narrowband Synergy\" approach uses the L-Quad Enhance filter to acquire rich, natural RGB data from stars and galaxies, while the L-Para L1 dual-narrowband filter isolates the critical H-alpha and OIII emission lines that reveal the intricate structures within nebulae. By combining the data from both, you can produce images with vibrant, accurate color and deep, high-contrast details that are difficult to achieve with a single filter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eL-Quad Enhance: A Broadband Filter for True-Color Imaging\u003c\/h3\u003e\n\u003cp\u003eThe L-Quad Enhance is a quad-bandpass filter engineered to capture continuous-spectrum objects with superior color fidelity, even from light-polluted skies. It preserves the natural RGB color balance of targets like the Andromeda Galaxy (M31) or star clusters, improving overall contrast and making your subjects appear more vivid. This filter acts as the color foundation of your image, ensuring stars and galactic structures retain their true appearance.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eL-Para: Isolating Hα \u0026amp; OIII for Maximum Nebula Detail\u003c\/h3\u003e\n\u003cp\u003eThe L-Para is a dual-narrowband filter that selectively passes H-alpha and Oxygen-III emission lines, the two most important wavelengths for revealing the structure of emission nebulae. It is designed to deliver excellent contrast and anti-halo performance, making it highly effective even with very fast optical systems. By isolating these specific signals, the L-Para captures the fine, filamentary details and ionized gas morphology in targets like the Lagoon Nebula (M8) or Horsehead Nebula (B33).\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 Synergy Workflow: Fusing Broadband Color with Narrowband Data\u003c\/h3\u003e\n\u003cp\u003eThis two-filter set enables a powerful imaging workflow. You use the L-Quad Enhance to shoot your primary RGB frames, capturing the broadband color data. You then switch to the L-Para to gather dedicated H-alpha and OIII data. In post-processing software like PixInsight or Photoshop, these separate data sets are combined, allowing the rich color from the L-Quad to be layered with the sharp, high-contrast details from the L-Para, creating a final image with exceptional depth and clarity.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eDual-Filter Strategy vs. a Single Multi-Bandpass Filter\u003c\/h3\u003e\n\u003cp\u003eWhile a single tri- or quad-band filter captures all wavelengths simultaneously, this dual-filter strategy offers greater control and optimization. You can dedicate more imaging time to capturing the faint Hα and OIII signals with the L-Para, without overexposing the broadband data. This separation allows you to independently control the signal-to-noise ratio of your color and detail layers, giving you more flexibility in processing to achieve a customized final result.\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\u003eIon-Assisted Coatings for Wavelength Stability and Durability\u003c\/h3\u003e\n\u003cp\u003eBoth Optolong filters are manufactured using an ion-assisted deposition coating process. This advanced technique creates a dense, durable, and scratch-resistant surface. Critically, it ensures the central wavelength (CWL) of the filter passbands does not shift with temperature changes during an imaging session, providing consistent, reliable data from dusk till dawn.\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 Optolong L-Quad + L-Para set over a single filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis set offers superior \u003cstrong\u003eprocessing flexibility\u003c\/strong\u003e. By capturing broadband color (with the L-Quad) and narrowband detail (with the L-Para) separately, you have independent control over each data stream. This allows you to optimize exposure times for faint nebula structures without compromising natural star color, leading to a more dynamic and detailed final image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow would I use the Optolong dual-filter set on the Trifid Nebula (M20)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Trifid Nebula is a perfect target for this set. You would use the \u003cstrong\u003eL-Quad Enhance\u003c\/strong\u003e filter to capture the blue reflection nebula and the surrounding starfield in true color. Then, you would switch to the \u003cstrong\u003eL-Para filter\u003c\/strong\u003e to gather deep exposures of the red H-alpha emission regions. Combining these in post-processing will showcase both the vibrant reflection and emission components with maximum detail.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the L-Para filter in this Optolong set suitable for 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. The L-Para filter is specifically designed to perform exceptionally well with fast optical systems. It maintains high transmission for the H-alpha and OIII lines while controlling halos, ensuring you can capture high-contrast, detailed images of nebulae even with very short focal ratios.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong L-Quad Enhance filter by itself for galaxies?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. The L-Quad Enhance filter is an excellent standalone filter for broadband targets like galaxies and star clusters. It works as a light pollution filter that provides a much more natural color balance than typical multi-bandpass nebula filters, making it ideal for capturing continuous-spectrum objects.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of objects benefit most from the Optolong L-Para filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe L-Para filter excels on \u003cstrong\u003eemission nebulae\u003c\/strong\u003e. These are objects rich in ionized hydrogen (H-alpha) and oxygen (OIII). Prime targets include the Rosetta Nebula (NGC 2237), the Veil Nebula complex, and the North America Nebula (NGC 7000), where the filter will dramatically increase contrast and reveal faint structures.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does \"CWL stability\" mean for these Optolong filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eCWL stands for Central Wavelength. \"CWL stability\" means the filter's passbands will not drift or change even as the ambient temperature fluctuates throughout the night. This is ensured by Optolong's advanced coating technology and results in more consistent and reliable data collection during long imaging sessions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"Default Title","offer_id":50341802574109,"sku":"OPT-L1-SET","price":558.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-L1-Dual-Combo-Set.jpg?v=1757558556"},{"product_id":"optolong-ir-pass-685nm-planetary-filter","title":"Optolong IR Pass 685nm Planetary Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003ePasses infrared light above 685nm\u003c\/li\u003e\n\u003cli\u003eAchieves greater than 90% peak transmission\u003c\/li\u003e\n\u003cli\u003eBlocks wavelengths from 350-1050nm outside the passband\u003c\/li\u003e\n\u003cli\u003e1.85mm thick B270 substrate\u003c\/li\u003e\n\u003cli\u003eSurface quality of 60\/40 with λ\/4 transmitted wavefront\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong IR Pass 685nm Planetary Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong IR Pass 685nm Planetary Filter isolates the near-infrared region of the spectrum, transmitting wavelengths longer than 685nm with over 90% efficiency. Built on a 1.85mm B270 substrate, this filter leverages the fact that atmospheric turbulence has less effect on longer wavelengths of light, allowing your camera's sensor to capture a significantly steadier image. The filter maintains a λ\/4 transmitted wavefront and a 60\/40 surface quality, ensuring it reveals fine planetary detail without degrading your telescope's native optical resolution.\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\u003eStabilizing Planetary Views with a 685nm IR Cut-On\u003c\/h3\u003e\n\u003cp\u003eAtmospheric seeing, the blurring caused by air currents, is the primary obstacle to high-resolution planetary imaging. The Optolong IR Pass 685nm filter acts as a powerful tool to mitigate this effect by blocking visible light and passing only near-infrared light, which is less susceptible to atmospheric distortion. This results in a much sharper, higher-contrast monochrome image that can serve as a powerful luminance layer (an \"IR-LRGB\" composite) for your final color image.\u003c\/p\u003e\n\u003cp\u003eWhen imaging planets like Jupiter, Saturn, or Mars, using the 685nm IR Pass as your luminance channel captures fine details in cloud bands and surface features that are often lost in the turbulence of a standard LRGB sequence. Your CMOS or CCD sensor, sensitive to light from 350-1050nm, can take full advantage of this stable IR signal to produce results that cut through 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\u003eλ\/4 Wavefront and \u0026gt;90% Transmission Coatings\u003c\/h3\u003e\n\u003cp\u003eOptolong constructs the IR Pass 685nm filter with exacting optical standards to preserve the integrity of your image. A transmitted wavefront of λ\/4 and parallelism of 30 arcseconds guarantee that the filter will not introduce aberrations or distortions into your optical train. The advanced multi-layer coatings, applied using an ion-assisted deposition process, achieve greater than 90% transmission in the target passband while delivering deep \u0026gt;99% blocking of light pollution lines and other unwanted wavelengths.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSubstrate and Thickness:\u003c\/strong\u003e The 1.85mm B270 glass substrate ensures parfocality with other filters of similar thickness, minimizing the need to refocus when switching filters.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDurable Coatings:\u003c\/strong\u003e The ion-assisted coating process produces a hard, scratch-resistant surface that is stable and will not degrade over time or with changes in temperature.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSurface Quality:\u003c\/strong\u003e A 60\/40 surface quality specification meets military standards, ensuring a clean and defect-free optical surface for maximum image contrast.\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 Optolong IR Pass 685nm filter for planets?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIts primary advantage is \u003cstrong\u003ereducing the effect of atmospheric turbulence (seeing)\u003c\/strong\u003e. Longer wavelengths of light, like the infrared light passed by this filter, are less distorted by the atmosphere. This allows you to capture a much sharper, steadier image of planets, which can be used as a high-detail luminance layer to dramatically improve your final color planetary photos.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow would the Optolong IR Pass 685nm 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\u003eOn a typical night of average seeing, an 8\" SCT can resolve significant detail on Jupiter, but this detail is often blurred by the atmosphere. The Optolong IR Pass 685nm filter will produce a monochrome image that is noticeably sharper than what you'd get with a standard luminance filter. Details within the Great Red Spot, smaller storms, and fine structures in the main equatorial belts will be more defined, providing a superior foundation for your final IR-LRGB image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong IR Pass 685nm filter for visual observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this is an imaging-only filter. It blocks all visible light below 670nm, a region where the human eye is most sensitive. Looking through an eyepiece with this filter in place will result in a completely black field of view.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is the Optolong IR Pass 685nm filter a good choice for imaging Mars with my C11?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA C11 has tremendous resolving power, but that power is often limited by atmospheric seeing. The Optolong IR Pass 685nm filter is an excellent choice for Mars because it helps stabilize the image and increases contrast between the dark albedo features (like Syrtis Major) and the lighter desert regions. It's particularly effective at cutting through thin Martian atmospheric haze and dust, revealing surface details more clearly.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does this filter work with a color camera versus a mono camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eWith a mono camera\u003c\/strong\u003e, you use the Optolong IR Pass 685nm filter to capture a high-resolution luminance (L) channel, then combine it with separate Red, Green, and Blue channels for a full-color IR-LRGB image. \u003cstrong\u003eWith a color camera\u003c\/strong\u003e, you can use the filter to capture a monochrome video stream. You can then debayer this video as monochrome to create a sharp luminance layer and combine it with a separate, unfiltered color recording from the same session.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat do the λ\/4 wavefront and 60\/40 surface quality specs mean for my images?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThese specifications refer to the optical precision of the filter. \u003cstrong\u003eλ\/4 (1\/4 wave) transmitted wavefront\u003c\/strong\u003e means the filter is extremely flat and will not distort the light passing through it, preserving the sharpness delivered by your telescope. \u003cstrong\u003e60\/40 surface quality\u003c\/strong\u003e is a standard that limits the number and size of scratches and digs on the filter's surface, ensuring a clean, high-contrast image free of artifacts.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eB270\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eThickness\u003c\/td\u003e\n\u003ctd\u003e1.85mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAverage Transmission\u003c\/td\u003e\n\u003ctd\u003eT\u0026gt;90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Range\u003c\/td\u003e\n\u003ctd\u003e350-1050nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Depth\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;99% (Light Pollution Lines)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront RMS\u003c\/td\u003e\n\u003ctd\u003eλ\/4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30s\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eOptolong IR Pass 685nm Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eProtective Case\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":50341809914141,"sku":"OPT-12101","price":110.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":50341809946909,"sku":"OPT-12102","price":161.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-IR-Pass-685nm-Filter-2-inch.jpg?v=1757559032"},{"product_id":"optolong-variable-polarizing-filter","title":"Optolong Variable Polarizing Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eContinuously Variable Light Transmission\u003c\/li\u003e\n\u003cli\u003eAvailable in 1.25\" and 2\" Barrel Sizes\u003c\/li\u003e\n\u003cli\u003eIdeal for Lunar, Planetary, and Terrestrial Viewing\u003c\/li\u003e\n\u003cli\u003eReduces Glare and Enhances Contrast\u003c\/li\u003e\n\u003cli\u003eDurable CNC-Machined Metal Cell\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong Variable Polarizing Filter\u003c\/h2\u003e\n\u003cp\u003eAvailable in both 1.25\" and 2\" barrel sizes, the Optolong Variable Polarizing Filter allows you to continuously adjust image brightness, providing precise glare control on the Moon and bright planets by simply rotating the filter housing.\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\u003eFine-Tune Brightness on the Moon, Venus, and More\u003c\/h3\u003e\n\u003cp\u003eUnlike a standard, fixed-transmission Moon filter, a variable polarizer acts like a dimmer switch for your eyepiece. By rotating the top half of the two-piece filter, you can dial in the perfect amount of light attenuation for any target. This allows you to apply maximum filtering to reduce the overwhelming glare of a full Moon, then back it off to preserve detail on a delicate crescent Moon or when observing Venus.\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\u003eBeyond Astronomy: Cutting Glare in Terrestrial Viewing\u003c\/h3\u003e\n\u003cp\u003eThis filter's utility extends to daytime terrestrial observation and photography. Just like a polarizing filter on a DSLR camera, the Optolong Variable Polarizer enhances views by cutting through reflected glare. When observing over water or through atmospheric haze, a simple turn of the filter can dramatically increase contrast and make distant details pop.\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 Glass Construction in a CNC-Machined Cell\u003c\/h3\u003e\n\u003cp\u003eOptolong builds this filter with high-quality Schott glass, which is then multi-coated using an ion-assisted deposition process. This technique ensures the coatings are durable, scratch-resistant, and optically stable. The filter cell is CNC-machined from lightweight, strong metal, then sand-blasted and black-anodized for maximum durability and stray light control. The result is a slim, robust filter that won't vignette and is built to last.\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\u003eVariable Polarizer vs. Fixed Moon Filter: The Key Difference\u003c\/h3\u003e\n\u003cp\u003eA standard Moon filter is a single piece of neutral density glass with a fixed transmission percentage. It works, but it's a one-size-fits-all solution. A variable polarizing filter offers critical flexibility.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFixed Moon Filter:\u003c\/strong\u003e Provides one level of brightness reduction. May be too dark for a crescent Moon or not dark enough for a full Moon at high power.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptolong Variable Polarizer:\u003c\/strong\u003e Lets you set the brightness precisely for the target, your telescope's aperture, and the current seeing conditions, ensuring you never over- or under-dim the view.\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 do I adjust the brightness with the Optolong Variable Polarizing Filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eSimply thread the filter onto a 1.25\" or 2\" eyepiece or accessory. Then, while looking through the eyepiece, slowly rotate the top ring of the filter. You will see the image brightness change, allowing you to set the most comfortable and detailed view.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat's the main advantage of the Optolong Variable Polarizing Filter over a standard Moon filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe key advantage is \u003cstrong\u003eflexibility\u003c\/strong\u003e. A standard Moon filter has a fixed light reduction (e.g., 25% or 13% transmission). The Optolong Variable Polarizing Filter allows you to continuously adjust the brightness, making it adaptable to any lunar phase, planet, or even daytime terrestrial viewing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong Variable Polarizing Filter for observing the Sun?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eAbsolutely not.\u003c\/strong\u003e The Optolong Variable Polarizing Filter is \u003cstrong\u003eNOT a solar filter\u003c\/strong\u003e and is not designed for direct solar observation. Attempting to view the Sun with this filter will cause immediate and permanent eye damage and will destroy your equipment. Only use certified solar filters for solar viewing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Optolong Variable Polarizing Filter improve views of the Moon through my 8\" SCT?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, it's an excellent tool for an 8\" SCT. The large aperture of your telescope gathers a great deal of light, making the Moon uncomfortably bright. The Optolong Variable Polarizing Filter allows you to reduce the glare to a comfortable level, which increases contrast and makes it easier to see fine details like rilles, crater walls, and maria.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong Variable Polarizing Filter work for daytime, terrestrial viewing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFor terrestrial use, the Optolong Variable Polarizing Filter cuts down on polarized, reflected light. This is especially effective for reducing glare from water, glass, or wet surfaces. By rotating the filter, you can darken the sky, enhance the color of foliage, and see through reflections, improving overall image contrast.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eI'm trying to photograph a waterfall with my telescope; will the Optolong Variable Polarizing Filter help?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. When used for terrestrial photography, the Optolong Variable Polarizing Filter will reduce the harsh glare off the water's surface and wet rocks. This will allow your camera to capture more saturated colors and detail that would otherwise be washed out by reflections.\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\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eGlass Material\u003c\/td\u003e\n\u003ctd\u003eSchott Glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoatings\u003c\/td\u003e\n\u003ctd\u003eMulti-coated with ion-assisted deposition\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCell Material\u003c\/td\u003e\n\u003ctd\u003eCNC Machined, Anodized Metal\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Round Mounted","offer_id":50344085651741,"sku":"OPT-12501","price":52.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":50344085684509,"sku":"OPT-12502","price":64.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/optolong-variable-polarising-filter-2-inch-237882_700x700_jpg.webp?v=1757631904"},{"product_id":"optolong-l-synergy-7nm-sii-oiii-dual-narrowband-filter","title":"Optolong L-Synergy 7nm SII\/OIII Dual Narrowband Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eCaptures Sulfur-II and Oxygen-III Emission Lines Simultaneously\u003c\/li\u003e\n\u003cli\u003eEngineered for Hubble Palette (SHO) Imaging with Color Cameras\u003c\/li\u003e\n\u003cli\u003eStrict 7nm Bandpass for High-Contrast Views in Light Pollution\u003c\/li\u003e\n\u003cli\u003eDesigned to Complement Standard Ha\/OIII Dual-Band Filters\u003c\/li\u003e\n\u003cli\u003eIon-Assisted Coatings for Durability and Wavelength Stability\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\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong L-Synergy 7nm SII\/OIII Dual Narrowband Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong L-Synergy 7nm SII\/OIII Dual Narrowband Filter is a specialized tool designed to unlock Hubble Palette (SHO) astrophotography for color camera users. By isolating the Sulfur-II and Oxygen-III emission lines within a tight 7nm bandpass, this filter captures the two signals that standard dual-band filters miss. When combined with data from a traditional Ha\/OIII filter, the L-Synergy enables you to produce full three-channel narrowband images without investing in a monochrome camera and filter wheel.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe L-Synergy Concept: SHO Imaging with a 7nm Color Camera Filter\u003c\/h3\u003e\n\u003cp\u003eTraditional SHO imaging requires a monochrome camera and three separate filters for Hydrogen-alpha, Sulfur-II, and Oxygen-III. The L-Synergy filter provides a more accessible path by targeting the missing data for a one-shot-color sensor. Paired with an existing Ha\/OIII filter, this 7nm SII\/OIII filter completes the dataset, allowing you to separate and process all three signals to create vibrant Hubble Palette composites.\u003c\/p\u003e\n\u003cp\u003eThis dual-filter strategy dramatically simplifies both the hardware required and the post-processing workflow. By capturing strong, distinct signal for both SII and OIII, the raw data is cleaner and requires less aggressive stretching or gradient removal, leading to a more natural final image with minimal effort.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eIsolating Sulfur and Oxygen: A 7nm Bandpass for Maximum Contrast\u003c\/h3\u003e\n\u003cp\u003eThe filter's strict 7nm bandpass is the key to its high-contrast imaging. This narrow window transmits nearly all light from the targeted SII and OIII emission lines while aggressively blocking out light pollution, moonlight, and airglow. This selective transmission results in a significantly darker sky background, making faint nebular structures stand out with enhanced detail and signal-to-noise ratio, even from urban or suburban locations.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eIon-Assisted Deposition Coatings for Wavelength Stability\u003c\/h3\u003e\n\u003cp\u003eOptolong utilizes an advanced ion-assisted deposition coating process to manufacture the L-Synergy filter. This technique produces a hard, scratch-resistant surface and ensures the central wavelength of the filter does not shift due to temperature changes during an imaging session. This stability guarantees that your filter consistently captures the intended emission lines, preventing signal loss and maintaining color fidelity throughout the night.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eL-Synergy Method vs. Traditional Monochrome SHO Imaging\u003c\/h3\u003e\n\u003cp\u003eChoosing an imaging strategy involves trade-offs between cost, complexity, and ultimate signal purity. The L-Synergy method offers a compelling alternative to a full monochrome setup.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMonochrome SHO Advantage:\u003c\/strong\u003e A monochrome camera with dedicated filters offers the highest possible resolution and signal sensitivity, as it avoids the light loss inherent in a color camera's Bayer matrix. It remains the gold standard for scientific-grade data.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eL-Synergy Advantage:\u003c\/strong\u003e This method delivers results that are comparable to monochrome for a fraction of the cost and complexity. It allows you to use your existing DSLR or color CMOS camera, avoiding the need for a new camera, electronic filter wheel, and a full set of narrowband 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\"\u003eHow does the Optolong L-Synergy filter create Hubble Palette images with a color camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe L-Synergy filter captures the \u003cstrong\u003eSulfur-II (SII) and Oxygen-III (OIII)\u003c\/strong\u003e signals. You use it in conjunction with a separate Ha\/OIII filter. By combining the data from both filters, you can isolate the Ha, SII, and OIII channels in post-processing and assign them to the Red, Green, and Blue channels of a final image to create the classic SHO Hubble Palette.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat other filter do I need to use with the Optolong L-Synergy?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eTo capture a complete SHO dataset, you need to pair the L-Synergy (SII\/OIII) filter with a standard dual-band filter that captures \u003cstrong\u003eHydrogen-alpha (Ha) and Oxygen-III (OIII)\u003c\/strong\u003e, such as the Optolong L-eNhance or L-eXtreme.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Optolong L-Synergy 7nm filter work well with my fast telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis filter is optimized for telescope systems with focal ratios of \u003cstrong\u003ef\/3.3 and slower\u003c\/strong\u003e. Using it with faster optical systems (e.g., f\/2) may cause a shift in the filter's bandpass, leading to reduced signal transmission and a potential loss of performance. For the best results, it should be used within its recommended focal ratio range.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong L-Synergy filter improve imaging from a light-polluted city?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe filter's tight \u003cstrong\u003e7nm bandpass\u003c\/strong\u003e blocks out the broad-spectrum light common to urban light pollution (like sodium and mercury vapor lamps) and natural skyglow. It only allows the specific light from emission nebulae to pass through, dramatically increasing contrast and revealing faint details that would otherwise be washed out.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong L-Synergy to image the Wolf-Rayet nebula WR134?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. WR134 in Cygnus is an excellent target for the L-Synergy filter because its expanding shell is extremely rich in Oxygen-III, with some Sulfur-II signal as well. This filter is ideal for capturing the intricate blue-green arc of OIII that defines this object, which is often faint with other filter types.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow would the Optolong L-Synergy perform on the Heart Nebula (IC 1805)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Heart Nebula is another prime target. While known for its strong Hydrogen-alpha signal (which you'd capture with an Ha\/OIII filter), it also contains significant regions of Sulfur-II and Oxygen-III. The L-Synergy filter will capture the data needed to add the golden hues of SII and the teal tones of OIII, transforming the typically red nebula into a full, multi-colored Hubble Palette image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"Default Title","offer_id":50399317033245,"sku":"OPT-LSYNERGY","price":432.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-L-Synergy-Filter-1.jpg?v=1758936099"},{"product_id":"optolong-l-extreme-l-synergy-l2-dual-combo-filter-set-2","title":"Optolong L-Extreme + L-Synergy L2 Dual-Combo Filter Set - 2\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eIncludes L-eXtreme (H-alpha + OIII) and L-Synergy (SII + OIII) filters\u003c\/li\u003e\n\u003cli\u003eEnables Hubble Palette (SHO) imaging with one-shot color cameras\u003c\/li\u003e\n\u003cli\u003eCaptures three key nebula emission bands across two filters\u003c\/li\u003e\n\u003cli\u003eDesigned for modern, fast focal ratio telescope systems\u003c\/li\u003e\n\u003cli\u003eAdvanced ion-assisted coatings suppress halos and light pollution\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\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section-center\"\u003e\n      \u003ch2\u003eOptolong L-Extreme + L-Synergy L2 Dual-Combo Filter Set - 2\"\u003c\/h2\u003e\n      \u003cp\u003eThe Optolong L-Extreme + L-Synergy L2 Dual-Combo Filter Set is engineered to bring Hubble Palette imaging to one-shot color cameras, eliminating the need for a monochrome setup. This set combines the L-eXtreme (H-alpha and OIII) and L-Synergy (SII and OIII) dual-narrowband filters to isolate the three most important emission lines in deep-sky astrophotography. By capturing this data over two imaging sessions instead of one, you can create full SHO composite images with the operational simplicity of your existing color 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\u003eUnlocking the Hubble Palette for Color Cameras with the Optolong L2 Set\u003c\/h3\u003e\n      \u003cp\u003eHistorically, creating SHO \"Hubble Palette\" images required a monochrome camera, a filter wheel, and three separate narrowband filters—a costly and complex setup. The Optolong L2 Dual-Combo set breaks this barrier by intelligently pairing two dual-bandpass filters, allowing your color camera to collect all the necessary data to assemble a full SHO image, from the hydrogen greens of the North American Nebula (NGC 7000) to the sulfur reds of the Pelican Nebula (IC 5070).\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 L-eXtreme Filter: Capturing Ha and OIII in a Single Frame\u003c\/h3\u003e\n      \u003cp\u003eThe first filter in the set is the renowned L-eXtreme, which isolates the Hydrogen-alpha and Oxygen-III emission lines. These two signals represent the most dominant wavelengths in most emission nebulae. The filter transmits these specific bands while aggressively blocking light pollution and other unwanted signals, ensuring maximum contrast and signal-to-noise ratio for the H-alpha and OIII data channels in your final image.\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 L-Synergy Filter: Adding the Critical SII Signal for SHO\u003c\/h3\u003e\n      \u003cp\u003eThe L-Synergy filter completes the trio by isolating the Sulfur-II and Oxygen-III emission lines. While you capture OIII data with both filters, the L-Synergy's primary role is to gather the crucial SII signal, which forms the red channel in a traditional Hubble Palette. This filter provides the final piece of the puzzle, enabling a three-channel color mapping (SII=Red, Ha=Green, OIII=Blue) from data captured with just two filters.\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\u003eOptolong L2 Dual-Combo vs. Monochrome SHO: A Simpler Workflow\u003c\/h3\u003e\n      \u003cp\u003eFor imagers who want SHO results without the expense and learning curve of a monochrome system, the L2 Dual-Combo set is the direct solution. A monochrome setup's advantage is its ultimate control over data, but it requires more accessories, longer total integration times, and complex processing. The L2 set preserves the simplicity of color imaging—fewer cables, no filter wheel, and a more streamlined workflow—while delivering access to the same creative color palette previously reserved for mono users.\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 High-Contrast, Halo-Free Results\u003c\/h3\u003e\n      \u003cp\u003eBoth filters in the L2 set are manufactured using an ion-assisted deposition coating process. This technology ensures the filter coatings are physically durable, resistant to scratching, and stable against temperature shifts that can cause other filters to drift off-wavelength. The result is precise, consistent bandpass performance and excellent suppression of halos around bright stars, yielding clean, high-contrast data ready for processing.\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 Optolong L2 Dual-Combo Set create a Hubble Palette image with a color camera?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe set allows you to capture all three essential narrowband channels (H-alpha, OIII, and SII) using a one-shot color camera. You use the \u003cstrong\u003eL-eXtreme filter\u003c\/strong\u003e to capture Ha and OIII data, then the \u003cstrong\u003eL-Synergy filter\u003c\/strong\u003e to capture SII and OIII data. In processing, you separate the color channels from both data sets to isolate the individual signals and then combine them into an SHO (SII=Red, Ha=Green, OIII=Blue) image.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the imaging process for the L2 Dual-Combo filters with my 8\" f\/4 Newtonian?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe process involves two separate imaging sessions on the same target. First, install the L-eXtreme filter and capture a series of sub-exposures. On a subsequent night (or after the first session), swap to the L-Synergy filter and capture another series of subs with similar total integration time. Because the set is designed for fast optical systems like your f\/4 Newtonian, you can gather significant signal efficiently.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Optolong L2 filters work well with my fast refractor?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, this filter set is specifically designed to perform well with fast telescope systems. The coatings and bandpass characteristics are engineered to maintain signal integrity and minimize artifacts even at steep light cones, making them an excellent match for modern fast refractors and astrographs.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main advantage of the Optolong L2 set over using a monochrome camera?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe primary advantage is \u003cstrong\u003ecost and simplicity\u003c\/strong\u003e. The L2 Dual-Combo set allows you to achieve SHO imaging without purchasing a separate monochrome camera, an electronic filter wheel, and a full set of LRGB and SHO filters. It leverages the color camera you already own, resulting in a much lower barrier to entry for creating Hubble Palette images.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I combine the data from the L-eXtreme and L-Synergy filters?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eAfter calibrating and stacking your images from each filter separately, you will have two master files. Using software like PixInsight or Siril, you can split the RGB channels of each master. The red channel from the L-eXtreme data becomes your H-alpha. The red channel from the L-Synergy data becomes your SII. The blue\/green channels from either can be used for your OIII, often by combining them for better signal. You then assign these three extracted grayscale images to the R, G, and B channels of a new color image.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eDo these Optolong filters help reduce halos around bright stars?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes. Both the L-eXtreme and L-Synergy filters are manufactured with advanced coating techniques that significantly suppress internal reflections. This technology is optimized to minimize the bright, distracting halos that can appear around high-magnitude stars in long narrowband exposures.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"Default Title","offer_id":50923140808989,"sku":"OPT-L2-COMBO","price":796.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-L2Dual-Combo-Filter-Set.jpg?v=1770476463"},{"product_id":"optolong-h-alpha-3nm-filter","title":"Optolong H-alpha 3nm Narrowband Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e3nm Bandpass at 656nm Wavelength\u003c\/li\u003e\n\u003cli\u003eMaximizes Contrast for Emission Nebulae\u003c\/li\u003e\n\u003cli\u003eExtreme Rejection of Light Pollution and Skyglow\u003c\/li\u003e\n\u003cli\u003eIon-Assisted, Anti-Reflection Coatings\u003c\/li\u003e\n\u003cli\u003eThermally Stable Central Wavelength (CWL)\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\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong H-alpha 3nm Narrowband Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong H-alpha 3nm Narrowband Filter isolates the critical 656nm hydrogen-alpha emission line, providing the highest possible contrast for emission nebulae. Its extremely tight 3nm bandpass aggressively blocks light pollution from sources like mercury and sodium vapor lamps, as well as natural skyglow, revealing faint structural details that wider filters miss.\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 3nm Bandpass: Isolating the H-Alpha Signal at 656nm\u003c\/h3\u003e\n\u003cp\u003eThis filter is engineered for imagers seeking maximum signal-to-noise ratio from emission targets. The 3nm bandpass centered at 656nm transmits only the light from ionized hydrogen, creating a near-black sky background even from bright, urban locations. This extreme selectivity is the key to capturing the delicate, filamentary details in targets like the Veil Nebula (NGC 6960) or the faint outer regions of the Rosette Nebula (NGC 2237).\u003c\/p\u003e\n\u003cp\u003eFor astrophotographers building Hubble Palette (SHO) images with monochrome cameras, the 3nm H-alpha filter provides the foundational luminance layer with exceptional depth and contrast. It is the definitive choice for separating faint H-alpha structures from overwhelming light pollution.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eAdvanced Coatings for 3nm Filters: Thermal Stability and Halo Suppression\u003c\/h3\u003e\n\u003cp\u003eOptolong utilizes ion-assisted deposition coating technology to ensure durability, scratch resistance, and optical stability. This process produces uniform, multi-layer coatings that are critical for maintaining the filter's precise 3nm central wavelength (CWL) as ambient temperatures change during an imaging session. This stability prevents focus shift and ensures consistent data collection throughout the night.\u003c\/p\u003e\n\u003cp\u003eThese advanced coatings are also optimized to suppress halos around bright stars. By minimizing internal reflections, the 3nm H-alpha filter delivers clean star profiles, preserving the faint nebulosity that often surrounds prominent stars like Alnitak in the Horsehead Nebula (Barnard 33) region.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOptolong 3nm vs. 7nm H-Alpha: Choosing the Right Bandpass\u003c\/h3\u003e\n\u003cp\u003eThe choice between a 3nm and a 7nm filter depends on your imaging goals, location, and equipment. While both are excellent narrowband filters, they serve different primary purposes.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptolong 7nm H-Alpha:\u003c\/strong\u003e The 7nm filter gathers light more than twice as fast, allowing for shorter sub-exposures. This makes it more forgiving of minor tracking errors and a better choice for portable setups or when imaging time is limited. It provides a significant contrast boost over broadband filters and is an excellent all-around narrowband option.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptolong 3nm H-Alpha:\u003c\/strong\u003e The 3nm filter is the specialist's tool for ultimate contrast. It provides superior rejection of light pollution, moonlight, and skyglow. The trade-off is that it requires longer exposures and demands precise guiding and focus. For imagers in Bortle 7+ skies or those chasing the absolute faintest details, the 3nm filter's performance is unmatched.\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 choose the Optolong 3nm H-alpha filter over a 7nm version?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe 3nm bandpass offers the highest possible contrast and light pollution rejection, making it ideal for revealing extremely faint nebula details from urban or suburban skies. The trade-off is that it requires longer exposure times and more precise guiding compared to a 7nm filter, which gathers light faster.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong 3nm H-alpha filter perform under heavily light-polluted skies?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt excels in these conditions. The extremely narrow 3nm window passes only the H-alpha emission line at 656nm, while aggressively blocking broadband light from city lights, moonlight, and natural skyglow. This creates a near-black sky background, dramatically improving the signal-to-noise ratio of your images.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong 3nm H-alpha filter suitable for one-shot color cameras?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile designed for \u003cstrong\u003emonochrome cameras\u003c\/strong\u003e, it can be used with one-shot color (OSC) cameras, especially modified ones with greater red sensitivity. However, since it only passes light to the red pixels on the sensor, you will get a monochrome image that requires significant processing. For OSC cameras, a multi-bandpass filter is often a more efficient choice.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Optolong 3nm H-alpha filter help capture the Veil Nebula (NGC 6960) from my backyard?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Veil Nebula is rich in Hydrogen-alpha, but its delicate, filamentary structure can be washed out by skyglow. The Optolong 3nm filter will isolate this Ha signal with extreme precision, allowing you to capture fine, high-contrast details in the Witch's Broom and surrounding nebulosity, even with a bright moon or city lights.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat exposure times should I expect for the North American Nebula (NGC 7000) with the Optolong 3nm H-alpha filter on an f\/5 refractor?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWith a fast f\/5 system and a modern monochrome CMOS camera, typical sub-exposure times for a bright target like the North American Nebula would range from \u003cstrong\u003e300 to 600 seconds (5 to 10 minutes)\u003c\/strong\u003e. The exact time depends on your camera's sensitivity and your desired signal-to-noise ratio, but the 3nm bandpass will require longer exposures than a wider filter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo I need to refocus when switching between Optolong's 3nm SHO filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eOptolong's 3nm filters are manufactured with high precision to be nearly parfocal. While minor focus adjustments may be needed due to temperature changes or optical tolerances, you should not require major refocusing when switching between the H-alpha, OIII, and SII 3nm filters in the same set.\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 Interference Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandpass\u003c\/td\u003e\n\u003ctd\u003e3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCentral Wavelength (CWL)\u003c\/td\u003e\n\u003ctd\u003e656nm (H-alpha)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating Technology\u003c\/td\u003e\n\u003ctd\u003eIon-assisted deposition, multi-layer anti-reflection\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Formats\u003c\/td\u003e\n\u003ctd\u003e36mm Round Unmounted, 2\" Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eOptolong H-alpha 3nm Narrowband Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eProtective 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\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"36mm Round Unmounted","offer_id":50923151556893,"sku":"OPT-14103","price":474.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":50923151589661,"sku":"OPT-14102","price":586.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-H-alpha-3nm-Filter-1.jpg?v=1770478823"},{"product_id":"optolong-sii-3nm-narrowband-filter","title":"Optolong SII 3nm Narrowband Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eIsolates the Sulfur-II (SII) emission line for astrophotography\u003c\/li\u003e\n\u003cli\u003eExtremely narrow 3nm bandpass for maximum contrast\u003c\/li\u003e\n\u003cli\u003eDrastically reduces skyglow and common light pollution sources\u003c\/li\u003e\n\u003cli\u003eAdvanced ion-assisted anti-reflection coatings\u003c\/li\u003e\n\u003cli\u003eAvailable in 2\" mounted or 36mm unmounted formats\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section-center\"\u003e\n      \u003ch2\u003eOptolong SII 3nm Narrowband Filter\u003c\/h2\u003e\n      \u003cp\u003eThe Optolong SII 3nm Narrowband Filter isolates the critical Sulfur-II emission line with an extremely tight 3nm bandpass. This precision dramatically increases contrast against even severe light pollution, darkening the sky background to reveal the faintest structural details in emission nebulae that wider filters cannot resolve. By passing only a 3nm sliver of the spectrum, the filter effectively eliminates interference from mercury vapor, sodium vapor, and natural skyglow.\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 3nm Bandpass: Isolate Signal and Suppress Light Pollution\u003c\/h3\u003e\n      \u003cp\u003eAn ultra-narrow 3nm bandpass is the key to pulling faint nebula signal out of a bright sky. Compared to wider 7nm or 12nm filters, the 3nm design provides a significant boost in signal-to-noise ratio. This allows for longer sub-exposures from urban or suburban locations, capturing deep data that would otherwise be lost in the glare.\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 \"S\" in SHO: Building a 3nm Hubble Palette\u003c\/h3\u003e\n      \u003cp\u003eThe SII 3nm filter is an essential component for creating false-color Hubble Palette images. It captures the light emitted by ionized sulfur, which is typically mapped to the red channel in an SHO (SII, H-alpha, OIII) composite. This data reveals unique structures within star-forming regions and supernova remnants, adding depth, dimension, and scientific context to your final image.\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\u003eIon-Assisted Coatings for 3nm Thermal Stability\u003c\/h3\u003e\n      \u003cp\u003eMaintaining a precise 3nm bandpass requires advanced coating technology. Optolong utilizes an ion-assisted deposition process to create hard, scratch-resistant coatings that are exceptionally stable. This ensures the filter's central wavelength does not drift with temperature changes during an imaging session, preventing signal loss and guaranteeing consistent results from dusk until dawn.\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 the Optolong SII 3nm filter over a wider 7nm version?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe primary benefit of the \u003cstrong\u003e3nm bandpass\u003c\/strong\u003e is significantly higher contrast and better light pollution suppression. By blocking more of the unwanted skyglow, the 3nm filter produces a darker background and makes faint nebula details stand out more clearly, especially from urban or suburban locations.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong SII 3nm filter perform on the Soul Nebula (IC 1848)?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eFor a target like the Soul Nebula (IC 1848), the Optolong SII 3nm filter is excellent for isolating the delicate structures traced by ionized sulfur. This signal is often fainter than the dominant H-alpha, and the high contrast of the 3nm filter is crucial for capturing the wispy details and separating them from the background starfield, forming the basis of the red channel in a Hubble Palette image.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong SII 3nm filter with a color camera?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eWhile designed for monochrome cameras, you can use the Optolong SII 3nm filter with a one-shot-color (OSC) camera. However, because the camera's Bayer matrix only allows a fraction of the pixels (the red ones) to detect the SII signal, the resulting image will have lower resolution and require much longer total integration time compared to using a monochrome sensor.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong SII 3nm filter suitable for imaging from a Bortle 8 zone?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, absolutely. The Optolong SII 3nm filter is specifically designed for conditions like a Bortle 8 or 9 sky. Its extremely narrow 3nm bandpass aggressively rejects common sources of artificial light pollution, allowing you to capture clean narrowband data even from the middle of a city.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat role does the Optolong SII 3nm filter data play in a final Hubble Palette image?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eIn the standard SHO Hubble Palette, data from the Optolong SII 3nm filter is assigned to the \u003cstrong\u003eRed\u003c\/strong\u003e channel. H-alpha data is assigned to Green, and OIII data is assigned to Blue. The SII signal often highlights the shock fronts and outer edges of nebulae, providing the warm golden and reddish hues that define the iconic Hubble look.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the central wavelength of the Optolong SII 3nm filter shift with temperature?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo. The Optolong SII 3nm filter is manufactured with an ion-assisted deposition coating process. This creates a very stable filter that ensures the central wavelength (CWL) does not deviate due to temperature changes during your imaging session, leading to more consistent data collection.\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 Type\u003c\/td\u003e\n\u003ctd\u003eNarrowband\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eEmission Line\u003c\/td\u003e\n\u003ctd\u003eSulfur-II (SII)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eBandpass\u003c\/td\u003e\n\u003ctd\u003e3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eAvailable Formats\u003c\/td\u003e\n\u003ctd\u003e2\" Mounted, 36mm Round Unmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eCoating Technology\u003c\/td\u003e\n\u003ctd\u003eMulti-layer, anti-reflection with Ion-assisted deposition\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\"\u003eOptolong SII 3nm Narrowband 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 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\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"2\" Mounted","offer_id":52941908181277,"sku":"OPT-14202","price":587.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":52941908214045,"sku":"OPT-14203","price":475.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-SII-3nm-Narrowband-Filter-1_f02f4e7c-603a-4030-8e53-634290e38f82.jpg?v=1789592304"},{"product_id":"optolong-oiii-3nm-narrowband-filter","title":"Optolong OIII 3nm Narrowband Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e3nm Spectral Bandpass\u003c\/li\u003e\n\u003cli\u003e500nm Central Wavelength (OIII)\u003c\/li\u003e\n\u003cli\u003eIon-Assisted Multi-Layer Coatings\u003c\/li\u003e\n\u003cli\u003eOptimized for Monochrome Cameras\u003c\/li\u003e\n\u003cli\u003eAvailable in 2\" Mounted or 36mm 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\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong OIII 3nm Narrowband Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong OIII 3nm Narrowband Filter isolates the critical doubly-ionized oxygen emission lines at 495.9nm and 500.7nm with an extremely tight 3nm bandpass centered at 500nm. This precision allows you to capture maximum-contrast images of planetary nebulae and supernova remnants by aggressively rejecting light pollution and skyglow, revealing faint structural details even from urban locations or under a bright moon.\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 3nm Bandpass Advantage: Isolating the 500nm OIII Signal\u003c\/h3\u003e\n\u003cp\u003eBy restricting transmission to a mere 3nm window, this filter dramatically increases the signal-to-noise ratio of your images. It effectively blocks out interfering wavelengths from streetlights and atmospheric glow, darkening the sky background and making faint, blue-green OIII structures pop. This is the key to resolving the delicate shells of the Dumbbell Nebula (M27) or the intricate filaments of the Veil Nebula (NGC 6960).\u003c\/p\u003e\n\u003cp\u003eWhile primarily designed for monochrome cameras, this filter can be used with modified color cameras for extreme light pollution rejection. When combined with H-alpha and SII filters, the OIII 3nm filter is an essential component for creating stunning Hubble Palette (SHO) composites.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eAdvanced Coatings: Ion-Assisted Deposition for Durability and Halo Control\u003c\/h3\u003e\n\u003cp\u003eOptolong utilizes an advanced ion-assisted deposition coating process to ensure the filter's transmission characteristics are precise and uniform. This technology produces hard, scratch-resistant surfaces and guarantees the central wavelength (CWL) will not shift due to temperature changes during your imaging session.\u003c\/p\u003e\n\u003cp\u003eA significant focus of the 3nm design was minimizing the halos that can appear around bright stars in narrowband images. Through optimized coating techniques, this filter exhibits significantly improved halo performance compared to previous generations, ensuring that bright stars like Sadr in Cygnus don't overwhelm the surrounding nebulosity.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOptolong 3nm vs. 7nm OIII: When to Choose the Tighter Bandpass\u003c\/h3\u003e\n\u003cp\u003eChoosing between a 3nm and a 7nm filter involves a direct trade-off between contrast and exposure time. A wider 7nm filter is more forgiving, requires shorter sub-exposures, and is an excellent choice for darker skies or faster optical systems.\u003c\/p\u003e\n\u003cp\u003eThe 3nm filter is the superior tool when ultimate contrast is the goal. It provides a darker background and isolates the nebula signal more effectively, making it the ideal choice for imaging from heavily light-polluted areas or during bright moon phases. This higher contrast comes at the cost of requiring longer exposure times to achieve the same signal level, demanding accurate guiding and a stable 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\"\u003eWhat is the main advantage of the Optolong OIII 3nm filter over a 7nm version?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary advantage is \u003cstrong\u003ehigher contrast\u003c\/strong\u003e. The tighter 3nm bandpass more aggressively rejects background light from skyglow and artificial sources. This makes it superior for pulling out faint nebulosity from light-polluted skies or when imaging during a bright moon.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Optolong OIII 3nm filter help me image the Cygnus Loop (Veil Nebula) from my Bortle 8 backyard?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Veil Nebula is a classic OIII target. From a Bortle 8 location, the skyglow would normally overwhelm the nebula's faint, filamentary structure. The Optolong OIII 3nm filter blocks this light pollution, isolating the specific 500nm light from the nebula and dramatically increasing its visibility against a dark background, allowing you to capture details that would otherwise be impossible.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong OIII 3nm filter with a color camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile designed for monochrome sensors, you can use it with a one-shot-color (OSC) or modified DSLR camera. Since the filter only passes a narrow band of blue-green light, your resulting image will be monochrome. This is an effective strategy for extreme light pollution suppression with a color camera, but a dedicated monochrome camera will always provide a stronger signal.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat types of celestial objects are best suited for the Optolong OIII 3nm filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis filter excels on emission nebulae that are rich in doubly-ionized oxygen. Prime targets include:\n\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePlanetary Nebulae:\u003c\/strong\u003e The Dumbbell Nebula (M27), the Ring Nebula (M57), and the Helix Nebula (NGC 7293).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSupernova Remnants:\u003c\/strong\u003e The entire Veil Nebula complex (NGC 6960, 6992, 6995) and the Crab Nebula (M1).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSome Star-Forming Regions:\u003c\/strong\u003e Parts of the Orion Nebula (M42) and the Lagoon Nebula (M8) have significant OIII emission.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is halo control important for the Optolong OIII 3nm filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNarrowband filters can sometimes create faint rings, or halos, around very bright stars due to internal reflections within the filter glass. The Optolong OIII 3nm filter uses an advanced coating process specifically designed to minimize these artifacts. This ensures that when you're imaging a target near a bright star, the star remains a clean point of light without a distracting halo that could obscure faint, nearby details.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the Optolong OIII 3nm filter require longer exposures?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. Because the 3nm bandpass is so restrictive, it passes less total light than a wider 7nm or 12nm filter. To compensate and build up enough signal from the nebula, you will need to use longer sub-exposure times. This makes good polar alignment and accurate autoguiding essential for sharp results.\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\u003e2\" Mounted, 36mm Round Unmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandwidth (FWHM)\u003c\/td\u003e\n\u003ctd\u003e3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCentral Wavelength (CWL)\u003c\/td\u003e\n\u003ctd\u003e500nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission Lines\u003c\/td\u003e\n\u003ctd\u003eOIII (495.9nm and 500.7nm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating Technology\u003c\/td\u003e\n\u003ctd\u003eIon-Assisted Multi-layer Deposition\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Use\u003c\/td\u003e\n\u003ctd\u003eMonochrome CCD\/CMOS Cameras\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eOptolong OIII 3nm Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eProtective Case\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"2\" Mounted","offer_id":52941909426461,"sku":"OPT-14302","price":587.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":52941909459229,"sku":"OPT-14303","price":475.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-OIII-3nm-Narrowband-Filter-1_a112b100-d463-447e-8461-e104641642f2.jpg?v=1789592313"},{"product_id":"optolong-sho-3nm-narrowband-filter-kit-3-pcs","title":"Optolong Ha, OIII \u0026 SII 3nm Narrowband Filter Set","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eComplete SHO set includes H-alpha, OIII, and SII filters\u003c\/li\u003e\n\u003cli\u003eUltra-narrow 3nm bandpass for maximum contrast\u003c\/li\u003e\n\u003cli\u003eIsolates 656nm Ha and 500nm OIII emission lines\u003c\/li\u003e\n\u003cli\u003eAdvanced coatings for halo suppression and durability\u003c\/li\u003e\n\u003cli\u003eIdeal for imaging in heavily light-polluted or moonlit skies\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\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong Ha, OIII \u0026amp; SII 3nm Narrowband Filter Set\u003c\/h2\u003e\n\u003cp\u003eThe Optolong Ha, OIII \u0026amp; SII 3nm Narrowband Filter Set provides the essential tools for creating high-contrast Hubble Palette images from light-polluted locations. This three-filter kit isolates the most critical emission lines in deep-sky objects with an extremely narrow 3nm bandpass, targeting H-alpha at 656nm and OIII at 500nm. By aggressively rejecting skyglow, moonlight, and artificial light sources, this SHO set delivers a near-black sky background, making faint nebular structures visible with striking clarity.\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\u003e3nm Bandpass: Isolate Emission Lines with Extreme Contrast\u003c\/h3\u003e\n\u003cp\u003eThe core of this filter set's power is its ultra-narrow 3nm full width at half maximum (FWHM). This level of precision allows only the light from specific ionized gases to reach your monochrome sensor, dramatically increasing the signal-to-noise ratio. The H-alpha filter captures the 656nm line characteristic of hydrogen, while the OIII filter isolates the dual 495.9nm and 500.7nm lines from doubly ionized oxygen, revealing the intricate structures within planetary nebulae and supernova remnants.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eAdvanced Coatings for Durability and Halo Suppression\u003c\/h3\u003e\n\u003cp\u003eOptolong utilizes an ion-assisted deposition coating process to ensure these filters are durable, scratch-resistant, and optically stable. This advanced manufacturing method maintains a consistent central wavelength that does not shift with temperature changes during an imaging session. Special attention has been paid to the OIII filter, which features an optimized coating design to significantly reduce the halos and internal reflections around bright stars that can compromise narrowband 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\u003eMastering the Hubble Palette: Building SHO Images\u003c\/h3\u003e\n\u003cp\u003eThis filter set is designed for creating false-color \"Hubble Palette\" images, where data from each filter is mapped to a specific color channel. By assigning the Sulphur-II (SII) data to red, Hydrogen-alpha (Ha) to green, and Oxygen-III (OIII) to blue (the SHO combination), you gain immense creative control over the final image. This technique is responsible for the iconic, high-impact astrophotography seen from the Hubble Space Telescope and allows you to highlight specific structures within a nebula based on its chemical composition.\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\u003e3nm vs. 7nm Filters: Choosing the Right Bandwidth\u003c\/h3\u003e\n\u003cp\u003eWhile wider 7nm filters gather light more quickly, allowing for shorter individual exposures, they are more susceptible to light pollution and moonlight. The primary advantage of the Optolong 3nm filter set is its superior rejection of unwanted light, which is a decisive factor in urban or suburban skies.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eContrast:\u003c\/strong\u003e The 3nm bandpass delivers a significantly darker sky background and higher contrast on emission targets, making it the better choice for revealing the faintest details.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExposure Time:\u003c\/strong\u003e The narrower bandpass requires longer total integration time to achieve the same signal level as a 7nm filter. However, the resulting data is often cleaner and requires less aggressive processing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStar Control:\u003c\/strong\u003e The 3nm filters pass less continuum light from stars, resulting in smaller, tighter stars in the final image, which further enhances the visibility of the nebula itself.\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 Optolong 3nm SHO filter set over wider filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe main advantage is \u003cstrong\u003econtrast\u003c\/strong\u003e. The ultra-narrow 3nm bandpass is extremely effective at blocking out light pollution, skyglow, and moonlight. This results in a much darker background and allows faint details in emission nebulae to stand out more clearly, which is especially critical for imaging from urban or suburban locations.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong 3nm SHO set perform under a full moon or in Bortle 8\/9 skies?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis set excels in such conditions. Narrowband imaging is the preferred technique for challenging skies, and a 3nm bandpass is the most aggressive tool for the job. While a bright moon will still have some impact, these filters allow you to continue imaging targets like the North American Nebula (NGC 7000) even when broadband LRGB imaging would be impossible.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong 3nm filters with a color camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile designed for monochrome cameras, you can use them with a color camera, but it's inefficient. A color camera's Bayer matrix blocks roughly two-thirds of the incoming light for any given filter. For best results and to fully leverage the power of the 3nm bandpass, a \u003cstrong\u003emonochrome astronomy camera\u003c\/strong\u003e is strongly recommended.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is the OIII filter in the Optolong 3nm set specifically optimized for halo reduction?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eOIII filters are historically prone to producing halos or rings around very bright stars due to internal reflections within the filter glass. Optolong has applied its experience and advanced coating technologies to the 3nm OIII filter to minimize these artifacts, ensuring cleaner data, especially on targets within star-rich regions like the Cygnus constellation.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of objects are best suited for imaging with the Optolong 3nm SHO set, like the Cygnus Loop (NGC 6960)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis filter set is ideal for all types of emission nebulae. For a target like the Veil Nebula (Cygnus Loop), the results are spectacular. The \u003cstrong\u003eH-alpha\u003c\/strong\u003e filter will reveal the broad, rope-like hydrogen filaments, while the \u003cstrong\u003eOIII\u003c\/strong\u003e filter will isolate the delicate, blue-green shock fronts, which are extremely bright in oxygen. The SII provides additional structural detail for a full Hubble Palette composition.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I combine data from the Optolong Ha, OIII, and SII filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIn post-processing software like PixInsight or Photoshop, you combine the three monochrome images into a single color image. The most common method is the \u003cstrong\u003eHubble Palette (SHO)\u003c\/strong\u003e:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eAssign the \u003cstrong\u003eSII\u003c\/strong\u003e image to the Red channel.\u003c\/li\u003e\n\u003cli\u003eAssign the \u003cstrong\u003eH-alpha\u003c\/strong\u003e image to the Green channel.\u003c\/li\u003e\n\u003cli\u003eAssign the \u003cstrong\u003eOIII\u003c\/strong\u003e image to the Blue channel.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThis creates the classic gold-and-blue Hubble look, which you can then adjust for color balance and aesthetics.\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 Interference Filter Set\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eIncluded Filters\u003c\/td\u003e\n\u003ctd\u003eH-alpha, Oxygen III, Sulphur II\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandpass (FWHM)\u003c\/td\u003e\n\u003ctd\u003e3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCentral Wavelength (H-Alpha)\u003c\/td\u003e\n\u003ctd\u003e656nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCentral Wavelength (OIII)\u003c\/td\u003e\n\u003ctd\u003e500nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoatings\u003c\/td\u003e\n\u003ctd\u003eMulti-layer, Anti-Reflection, Ion-Assisted Deposition\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eOptical Glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e2\" Mounted, 36mm Round Unmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eOptolong H-alpha 3nm 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\"\u003eOptolong OIII 3nm 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\"\u003eOptolong SII 3nm Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eProtective Storage 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\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"2\" Mounted","offer_id":52941910901021,"sku":"OPT-SHO3NM-2","price":1679.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":52941910933789,"sku":"OPT-SHO3NM-RD36","price":1344.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-2021-NEW-Optolong-SHO-3nm-narrowband-filters-kit-1_af14908b-fe74-4be0-a7b8-3d92151a6b1b.jpg?v=1789592322"},{"product_id":"optolong-moon-skyglow-filter","title":"Optolong Moon \u0026 Skyglow Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eBlocks over 99% of common light pollution emission lines\u003c\/li\u003e\n\u003cli\u003eMaintains over 90% average transmission for bright, detailed views\u003c\/li\u003e\n\u003cli\u003eλ\/4 transmitted wavefront ensures no image degradation\u003c\/li\u003e\n\u003cli\u003eDurable B270 substrate with 1.85mm thickness\u003c\/li\u003e\n\u003cli\u003eAvailable in 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\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong Moon \u0026amp; Skyglow Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong Moon \u0026amp; Skyglow Filter dramatically improves visual and photographic contrast by blocking over 99% of disruptive artificial light pollution and natural skyglow. By maintaining an average transmission greater than 90% for desirable wavelengths, it darkens the sky background without dimming celestial targets, all while preserving image sharpness with a λ\/4 transmitted wavefront across its 1.85mm thick B270 glass substrate.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e\u0026gt;99% Light Pollution Rejection with \u0026gt;90% Transmission\u003c\/h3\u003e\n\u003cp\u003eThis filter isolates and rejects the most common sources of light pollution, such as sodium vapor streetlights, darkening the sky background to make faint details visible. With a high transmission rate of over 90% across the visible spectrum, galaxies, nebulae, and star clusters retain their brightness and structure, resulting in a significantly higher-contrast view.\u003c\/p\u003e\n\u003cp\u003eThis balanced approach makes the Moon \u0026amp; Skyglow filter highly versatile. It provides a noticeable improvement from moderately light-polluted skies without the aggressive color shifting of narrowband filters, making it an ideal general-purpose tool for both visual observing and astrophotography.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eλ\/4 Wavefront Accuracy and Durable B270 Construction\u003c\/h3\u003e\n\u003cp\u003eAn astronomical filter is useless if it degrades the sharp image from your telescope. Optolong constructs the Moon \u0026amp; Skyglow filter from B270 optical glass polished to a λ\/4 transmitted wavefront accuracy and 30s parallelism. These specifications ensure that the filter will not introduce aberrations or distortions, preserving the fine details on planetary surfaces and the pinpoint sharpness of stars.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eIon-Assisted Coatings:\u003c\/strong\u003e Precision coatings are applied using an ion-assisted deposition process, ensuring durability, scratch resistance, and stable performance that does not shift with temperature changes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e60\/40 Surface Quality:\u003c\/strong\u003e This specification controls for cosmetic imperfections, guaranteeing a clean optical surface that won't scatter light or reduce contrast.\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 primary purpose of the Optolong Moon \u0026amp; Skyglow filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Optolong Moon \u0026amp; Skyglow filter is a broadband light pollution filter designed to increase the contrast of celestial objects. It selectively blocks common wavelengths of artificial light and natural skyglow, which darkens the sky background and makes faint details on the Moon, planets, galaxies, and nebulae easier to see.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Optolong Moon \u0026amp; Skyglow filter 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 washes out the faint, outer structures of nebulae like M42. The Optolong Moon \u0026amp; Skyglow filter blocks this interfering light, making the sky background appear much darker. This allows the faint nebulosity extending from the core of the Orion Nebula to stand out, revealing more of its intricate dust lanes and structure.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong Moon \u0026amp; Skyglow filter effective for planetary viewing in an 8\" SCT?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, it can be beneficial. While planets are bright, they are often observed against a bright sky background, especially at lower altitudes. The filter darkens the sky immediately surrounding the planet, which can increase the perceived contrast of subtle details like Jupiter's cloud bands or Saturn's Cassini Division. It also helps reduce glare when observing the bright lunar surface.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong Moon \u0026amp; Skyglow filter suitable for astrophotography?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this filter is very effective for astrophotography, particularly with one-shot color cameras. By blocking over 99% of major light pollution sources, it allows for longer sub-exposures before the skyglow saturates the sensor. This results in cleaner images with better contrast and more natural star colors compared to unfiltered shots from a light-polluted area.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does the λ\/4 wavefront specification mean for the Optolong Moon \u0026amp; Skyglow filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA \u003cstrong\u003eλ\/4 (1\/4 wave)\u003c\/strong\u003e wavefront rating is a measure of optical precision. It guarantees that the filter's glass is flat and parallel enough that it will not distort the light passing through it by more than one-quarter of a wavelength of light. This is critical for high-resolution viewing and imaging, as it ensures the filter will not degrade the sharpness of the image produced by your telescope.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong Moon \u0026amp; Skyglow filter for solar observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eAbsolutely not.\u003c\/strong\u003e This filter is designed for night-sky use only and provides no protection from the Sun's harmful radiation. Looking at the Sun with this filter, or any filter not specifically designed for safe solar observation, will cause immediate and permanent eye damage, including blindness. Always use a certified solar filter that covers the front of your telescope.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eB270 Optical Glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eThickness\u003c\/td\u003e\n\u003ctd\u003e1.85mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAverage Transmission\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Depth\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;99% (on light pollution lines)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront RMS\u003c\/td\u003e\n\u003ctd\u003eλ\/4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30s\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eOptolong Moon \u0026amp; Skyglow Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eProtective Case\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":52941911294237,"sku":"OPT-10501","price":45.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":52941911327005,"sku":"OPT-10502","price":67.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-Moon-Skyglow-Filter-1_176bee0d-3759-4793-929e-bc873bad8163.jpg?v=1789592332"},{"product_id":"optolong-clear-sky-filter","title":"Optolong Clear Sky Light Pollution Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eSuppresses common sources of urban light pollution\u003c\/li\u003e\n\u003cli\u003eEnhances contrast for deep-sky objects\u003c\/li\u003e\n\u003cli\u003eImproves natural color balance in astrophotography\u003c\/li\u003e\n\u003cli\u003eDurable, scratch-resistant Ion-assisted coatings\u003c\/li\u003e\n\u003cli\u003eAvailable in M77\/M82 lens thread and Nikon Z clip-in formats\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section-center\"\u003e\n      \u003ch2\u003eOptolong Clear Sky Light Pollution Filter\u003c\/h2\u003e\n      \u003cp\u003eThe Optolong Clear Sky Light Pollution Filter is engineered to reclaim the natural contrast and color of the night sky from light-polluted locations. By selectively blocking the most common wavelengths of artificial lighting, this filter allows the faint light from nebulae and galaxies to stand out against a darker background. It utilizes advanced ion-assisted deposition coatings to ensure durability and stable performance, making it an essential tool for DSLR and mirrorless camera astrophotography in urban and suburban environments.\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\u003eRestoring Natural Sky Contrast from the City\u003c\/h3\u003e\n      \u003cp\u003eShooting from a city or suburb washes out faint deep-sky objects, blending them into a bright, hazy background. The Optolong Clear Sky filter targets and suppresses the spectral lines of common streetlights and artificial skyglow, effectively darkening the sky without altering the natural color of stars and galaxies. This process dramatically enhances the contrast between your target and the background, revealing detail that would otherwise be lost.\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\u003eIon-Assisted Coatings for Durability and Color Fidelity\u003c\/h3\u003e\n      \u003cp\u003eOptolong employs a sophisticated ion-assisted deposition coating process to create a filter that is both effective and resilient. This technology produces a hard, scratch-resistant surface and ensures the central wavelength of the filter remains stable regardless of temperature changes during an imaging session. The precision and homogeneity of these coatings result in high transmission of desirable wavelengths, preserving true-to-life color balance for a more natural final image.\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 Optolong Clear Sky Filter improve astrophotography from a city?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe Optolong Clear Sky Filter works by selectively blocking the most common wavelengths of light emitted by artificial sources like sodium and mercury-vapor streetlights. This darkens the sky background in your images, which significantly \u003cstrong\u003eincreases the contrast\u003c\/strong\u003e of celestial objects like galaxies and nebulae, making them stand out more clearly.\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 Optolong Clear Sky filter and a stronger nebula filter like a UHC?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe Clear Sky filter is a \u003cstrong\u003ebroadband light pollution filter\u003c\/strong\u003e, designed to improve contrast while maintaining natural star color, making it great for galaxies and star clusters. A UHC (Ultra High Contrast) filter is a \u003cstrong\u003enarrowband filter\u003c\/strong\u003e that passes only specific emission lines (like H-Beta and OIII), resulting in a much darker sky but also a significant color cast. UHC filters are specialized for emission nebulae, while the Clear Sky filter is more versatile.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Optolong Clear Sky Filter change the color of stars in my images?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe filter is designed to produce a natural color balance with minimal color cast. While any filter that removes parts of the spectrum will have some effect, the Optolong Clear Sky filter aims to preserve the natural coloration of stars and broadband targets like galaxies, making color correction in post-processing much simpler than with more aggressive narrowband filters.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I choose between the lens thread and clip-in versions of the Optolong Clear Sky Filter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eChoose the version based on your equipment and needs:\u003c\/p\u003e\n    \u003cul\u003e\n      \u003cli\u003e\n\u003cstrong\u003eLens Thread (M77, M82):\u003c\/strong\u003e This type screws directly onto the front of your camera lens, just like a standard UV filter. It's ideal if you primarily use one or two lenses with the same filter thread size.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eClip-in Filter:\u003c\/strong\u003e This version fits inside the camera body, just behind the lens mount. This allows you to use the filter with \u003cstrong\u003eany lens\u003c\/strong\u003e compatible with your camera body (e.g., Nikon Z mount), which is more economical if you frequently switch between different lenses.\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 Optolong Clear Sky Filter to photograph the Andromeda Galaxy (M31) from a suburban backyard?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, absolutely. The Andromeda Galaxy (M31) is a perfect target for this filter. As a broadband object (a galaxy made of stars), it benefits greatly from the increased contrast the Clear Sky filter provides against a light-polluted suburban sky, helping to reveal its faint outer arms and dust lanes without distorting its natural color.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong Clear Sky Filter effective for shooting the Orion Nebula (M42) with a standard DSLR?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, the Optolong Clear Sky Filter is very effective for bright emission nebulae like the Orion Nebula (M42). It will help suppress local light pollution, making the faint, extended nebulosity more visible against a dark background while preserving the natural colors in the bright core and surrounding star field.\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 Mounting Options\u003c\/td\u003e\n\u003ctd\u003eM77 Lens Thread, M82 Lens Thread, Clip-in for Nikon Z Full Frame\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"M77 Lens Thread","offer_id":52941912113437,"sku":"OPT-10503","price":231.0,"currency_code":"CAD","in_stock":true},{"title":"M82 Lens Thread","offer_id":52941912146205,"sku":"OPT-10504","price":287.0,"currency_code":"CAD","in_stock":true},{"title":"Clip for Nikon Z Full Frame","offer_id":52941912178973,"sku":"OPT-CLEARSKY-NK-Z","price":139.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-Clear-Sky-Filter-Screw-on-Lens-1_70b48089-a026-41d6-a39c-0cb0db0499d1.jpg?v=1789592341"},{"product_id":"optolong-h-alpha-7nm-narrowband-filter","title":"Optolong H-Alpha 7nm Narrowband Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eIsolates the 656nm Hydrogen-alpha emission line\u003c\/li\u003e\n\u003cli\u003e7nm bandpass for maximum contrast\u003c\/li\u003e\n\u003cli\u003eBlocks mercury vapor, sodium vapor, and natural skyglow\u003c\/li\u003e\n\u003cli\u003eIdeal for SHO \"Hubble Palette\" and LRGB+Ha imaging\u003c\/li\u003e\n\u003cli\u003eIon-assisted multi-layer coatings for 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\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\u003eOptolong H-Alpha 7nm Narrowband Filter\u003c\/h2\u003e\n      \u003cp\u003eThe Optolong H-Alpha 7nm Narrowband Filter is an essential tool for deep-sky astrophotography, designed to isolate the hydrogen-alpha emission line at a 656nm wavelength. By restricting the bandwidth to just 7nm, this filter dramatically increases the contrast between emission nebulae and the background sky. It achieves this by aggressively blocking common sources of light pollution, including mercury and sodium vapor lights, as well as the natural skyglow caused by atmospheric oxygen emission.\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\u003e7nm Bandpass at 656nm: The Key to High-Contrast Nebula Imaging\u003c\/h3\u003e\n      \u003cp\u003eThe core of this filter's design is its extremely narrow 7nm bandpass centered on the 656nm H-alpha line. This precision allows you to capture the faint, intricate structures within emission nebulae like the Rosette Nebula (Caldwell 49) or the Pillars of Creation in the Eagle Nebula (M16), even under the glare of a full moon or from a light-polluted suburban backyard. The filter doesn't make the nebula brighter; it darkens the sky background so severely that the nebula's signal stands out in sharp relief, revealing details that would otherwise be completely lost.\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\u003eSHO \u0026amp; LRGB+Ha: Unlocking 2 Advanced Astrophotography Workflows\u003c\/h3\u003e\n      \u003cp\u003eThe H-Alpha 7nm filter is a cornerstone for two primary advanced imaging techniques. For monochrome camera users, it serves as the \"S\" (Sulfur-II), \"H\" (Hydrogen-alpha), and \"O\" (Oxygen-III) foundation for creating stunning \"Hubble Palette\" images. This technique allows you to continue imaging productively even when the moon is out, turning potential downtime into valuable data collection.\u003c\/p\u003e\n      \u003cp\u003eIt's also the first and most critical narrowband addition for imagers using a standard LRGB filter set. By capturing a separate H-alpha channel and blending it with your RGB data, you can dramatically enhance the structural detail and contrast of red nebulae while maintaining a natural star field color, adding a professional touch to your final images.\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\u003eIon-Assisted Coatings: Ensuring 0 CWL Deviation From Temperature Shifts\u003c\/h3\u003e\n      \u003cp\u003eOptolong utilizes an advanced ion-assisted deposition coating process to ensure the filter is both durable and optically stable. This technology produces a hard, scratch-resistant surface that stands up to regular cleaning and handling in the field. Critically, it also ensures the central wavelength (CWL) does not deviate with temperature changes during an imaging session, preventing your signal from drifting out of the narrow 7nm bandpass and maintaining consistent results from dusk till dawn.\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 purpose of the Optolong H-Alpha 7nm filter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe Optolong H-Alpha 7nm filter is designed for deep-sky astrophotography with monochrome or color cameras. Its primary function is to isolate the \u003cstrong\u003e656nm hydrogen-alpha wavelength\u003c\/strong\u003e with a very narrow \u003cstrong\u003e7nm bandpass\u003c\/strong\u003e. This dramatically increases contrast by blocking light pollution and natural skyglow, making it possible to capture faint emission nebulae.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong H-Alpha 7nm filter for visual observing?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThis filter is not recommended for visual use. Narrowband filters like this one have extremely low light transmission outside their specified bandpass, making the view through an eyepiece incredibly dim. They are designed for long-exposure astrophotography, where a camera sensor can accumulate light over many minutes or hours.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong 7nm H-Alpha filter help in light-polluted skies?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eLight pollution from city lights is primarily composed of specific wavelengths, such as those from \u003cstrong\u003emercury vapor\u003c\/strong\u003e and \u003cstrong\u003esodium vapor\u003c\/strong\u003e lamps. The Optolong H-Alpha 7nm filter is engineered to block these wavelengths completely, along with unwanted natural skyglow. By only allowing the 656nm light from the nebula to pass through, it creates a near-black sky background, making the nebula's signal stand out dramatically.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow would I use the Optolong H-Alpha 7nm filter to image the Rosette Nebula (Caldwell 49) from my backyard?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eTo image the Rosette Nebula with the Optolong H-Alpha 7nm filter, you would place it in your filter wheel or drawer in front of your monochrome camera. Because the filter is so restrictive, you will need to take long exposures, typically 5 to 20 minutes each, depending on your telescope's focal ratio. You would then stack many of these sub-exposures to create a final, high-contrast black-and-white image revealing the nebula's intricate hydrogen structures.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eI have an LRGB filter set and a monochrome camera. How do I incorporate the Optolong H-Alpha 7nm filter into my workflow?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe Optolong H-Alpha 7nm filter is the perfect first step into advanced LRGB imaging. You would capture your standard Luminance, Red, Green, and Blue data as usual. Then, you capture a separate set of exposures using the H-Alpha filter. In post-processing, you can blend this detailed H-alpha data into your red channel or use it as a separate luminance layer to significantly enhance the detail and \"pop\" of any emission regions within your target.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the \"SHO\" or \"Hubble Palette\" and how does the Optolong H-Alpha 7nm filter fit in?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe \"SHO\" or \"Hubble Palette\" is a popular narrowband imaging technique that assigns data from three different filters to the RGB channels of a color image. The Optolong H-Alpha 7nm filter provides the \"H\" data. Typically:\u003c\/p\u003e\n    \u003cul\u003e\n      \u003cli\u003e\n\u003cstrong\u003eSulfur-II (SII) data\u003c\/strong\u003e is mapped to the Red channel.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eHydrogen-alpha (H-alpha) data\u003c\/strong\u003e is mapped to the Green channel.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eOxygen-III (OIII) data\u003c\/strong\u003e is mapped to the Blue channel.\u003c\/li\u003e\n    \u003c\/ul\u003e\n    \u003cp\u003eThis creates false-color images with high scientific value and striking aesthetic appeal, famously used for images like the \"Pillars of Creation\" (M16).\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\u003eBandpass\u003c\/td\u003e\n\u003ctd\u003e7nm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eCentral Wavelength\u003c\/td\u003e\n\u003ctd\u003e656nm (Hydrogen-alpha)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eAvailable Formats\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, 36mm Round Unmounted\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\"\u003eOptolong H-Alpha 7nm Filter\u003c\/p\u003e\n        \u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/li\u003e\n    \u003cli class=\"DAV-grid-item\"\u003e\n      \u003cdiv\u003e\n        \u003cp class=\"DAV-item-title\"\u003eProtective 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\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":52941912965405,"sku":"OPT-11301","price":223.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":52941912998173,"sku":"OPT-11302","price":321.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":52941913030941,"sku":"OPT-11307","price":265.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-H-Alpha-7nm-Narrowband-Filter-Improved-Version-for-deepsky-nebula-imaging-1_75eadee5-ff2e-45d6-8d76-899d79b53119.jpg?v=1789592351"},{"product_id":"optolong-sii-6-5nm-narrowband-filter","title":"Optolong SII 6.5nm Narrowband Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eIsolates the Sulfur-II (SII) emission line at 672nm\u003c\/li\u003e\n\u003cli\u003eTight 6.5nm bandpass for maximum contrast\u003c\/li\u003e\n\u003cli\u003eEnables imaging in heavily light-polluted skies and during bright moonlight\u003c\/li\u003e\n\u003cli\u003eAdvanced ion-assisted multi-layer coatings for durability and stability\u003c\/li\u003e\n\u003cli\u003eAvailable in 1.25\" Mounted, 2\" Mounted, and 36mm 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\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong SII 6.5nm Narrowband Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong SII 6.5nm Narrowband Filter isolates a tight 6.5nm bandpass centered on the 672nm wavelength of doubly ionized sulfur. This precision allows imagers to capture the faint, structural details in emission nebulae, separating the specific SII signal from interfering light pollution and moonlight, which is critical when a 6.5nm window is all you have to work with.\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 for Sulfur-II Emission\u003c\/h3\u003e\n\u003cp\u003eThis filter is engineered to transmit light from the specific 672nm emission line characteristic of ionized sulfur. The extremely narrow 6.5nm bandpass dramatically increases contrast by rejecting all other wavelengths, rendering the faint structures within nebulae against a dark sky background. This is essential for revealing details that are otherwise lost in the noise of broadband imaging.\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\u003eImaging Through Moonlight and City Skyglow at 672nm\u003c\/h3\u003e\n\u003cp\u003eBy targeting only the 672nm SII line, the Optolong 6.5nm filter effectively blocks common sources of light pollution, including mercury vapor and sodium vapor streetlights. It also rejects natural skyglow from neutral oxygen emission, allowing you to continue imaging even under a full moon. This transforms weeks of potential downtime into productive imaging sessions, maximizing your time under the stars regardless of your location.\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 \"S\" in the Hubble Palette: Building Full-Color Narrowband Images\u003c\/h3\u003e\n\u003cp\u003eThe SII 6.5nm filter is a critical component of the \"SHO\" narrowband imaging trio, alongside Hydrogen-alpha and Oxygen-III filters. By assigning the data from each filter to a different color channel (Sulfur to Red, Hydrogen to Green, Oxygen to Blue), you can create the vibrant, high-contrast images famously associated with the Hubble Space Telescope. This technique reveals the chemical composition and structure of targets like the Pillars of Creation in the Eagle Nebula (M16).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eIon-Assisted Coatings for 6.5nm Stability and Durability\u003c\/h3\u003e\n\u003cp\u003eOptolong utilizes an advanced ion-assisted deposition coating process to ensure the filter's optical characteristics are precise and long-lasting. This technology produces a dense, scratch-resistant coating and guarantees the stability of the central wavelength (CWL). The 6.5nm bandpass will not deviate due to temperature changes during an imaging session, ensuring consistent, reliable data from dusk till dawn.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the primary use for the Optolong SII 6.5nm filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Optolong SII 6.5nm filter is designed for astrophotography of emission nebulae. It isolates the light emitted by ionized sulfur at a wavelength of 672nm, which dramatically increases the contrast of these objects, especially when used from light-polluted areas or as part of a multi-filter color composite image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the 6.5nm bandpass on the Optolong SII filter improve my images?\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 rejects more unwanted light from streetlights, moonlight, and natural skyglow compared to wider filters. This results in a darker sky background and higher contrast between your target nebula and the sky, allowing fainter details to be captured.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong SII 6.5nm filter for visual observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this filter is not recommended for visual use. The 6.5nm bandpass is so restrictive that it blocks nearly all visible light, making it impossible to see all but the very brightest nebulae. It is designed specifically for long-exposure imaging with sensitive astronomy cameras.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong SII 6.5nm filter perform on the Rosette Nebula (NGC 2244) from a light-polluted location?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Rosette Nebula has significant Sulfur-II emission. Using the Optolong SII 6.5nm filter from a suburban or city location will allow you to capture the delicate filamentary structures within the nebula that would normally be completely washed out by skyglow. It is an essential tool for revealing the full structure of this and similar star-forming regions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat other filters do I need with the Optolong SII 6.5nm for full-color narrowband imaging?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFor full-color \"Hubble Palette\" (SHO) imaging, you will need two other narrowband filters:\n\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eHydrogen-alpha (H-alpha) filter:\u003c\/strong\u003e Captures ionized hydrogen, typically the strongest signal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOxygen-III (OIII) filter:\u003c\/strong\u003e Captures ionized oxygen, which reveals high-energy regions.\u003c\/li\u003e\n\u003c\/ul\u003e\nCombining data from these three filters allows you to create detailed and scientifically interesting false-color images.\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Optolong SII 6.5nm filter work well with my fast f\/4 Newtonian telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile narrowband filters perform optimally with slower focal ratios, Optolong's advanced coatings provide excellent stability. With very fast optical systems (f\/4 and below), some narrowband filters can exhibit a slight shift in their central wavelength. However, the Optolong SII 6.5nm is widely used with fast telescopes and produces excellent results. For critical applications, ensure your imaging software can accommodate precise focus for each filter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eNarrowband Interference Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandpass\u003c\/td\u003e\n\u003ctd\u003e6.5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCentral Wavelength\u003c\/td\u003e\n\u003ctd\u003e672nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Emission Line\u003c\/td\u003e\n\u003ctd\u003eSulfur-II (SII)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating Technology\u003c\/td\u003e\n\u003ctd\u003eIon-Assisted Multi-layer Deposition\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eOptical Glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, 36mm Unmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eOptolong SII 6.5nm Narrowband 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 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\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":52941916373277,"sku":"OPT-11401","price":223.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":52941916406045,"sku":"OPT-11402","price":321.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":52941916438813,"sku":"OPT-11404","price":265.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-SII-6-5nm-imaging-narrow-band-filter-for-nebulae-photography-1_667ac9a4-9af1-4d52-a692-799938db0908.jpg?v=1789592369"},{"product_id":"optolong-oiii-6-5nm-narrowband-filter","title":"Optolong OIII 6.5nm Narrowband Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e6.5nm Narrowband OIII Filter\u003c\/li\u003e\n\u003cli\u003eCentered on 500nm Wavelength\u003c\/li\u003e\n\u003cli\u003eCaptures both 495.9nm and 500.7nm Emission Lines\u003c\/li\u003e\n\u003cli\u003eBlocks Light Pollution and Skyglow\u003c\/li\u003e\n\u003cli\u003eIdeal for SHO Hubble Palette Imaging\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section-center\"\u003e\n      \u003ch2\u003eOptolong OIII 6.5nm Narrowband Filter\u003c\/h2\u003e\n      \u003cp\u003eThe Optolong OIII 6.5nm Narrowband Filter isolates the critical emission lines of doubly-ionized oxygen by passing only a 6.5nm bandpass of light centered at a wavelength of 500nm. This extremely narrow window is engineered to capture both the 495.9nm and 500.7nm OIII lines, which are characteristic of planetary nebulae and supernova remnants, while aggressively rejecting unwanted light pollution and atmospheric skyglow.\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\u003eA 6.5nm Bandpass for High-Contrast OIII Imaging\u003c\/h3\u003e\n      \u003cp\u003eBy restricting the incoming light to a tight 6.5nm window, this filter dramatically increases the contrast between your target nebula and the background sky. The filter doesn't make the nebula brighter; it darkens the sky around it, causing the faint, blue-green structural details of OIII-rich objects to stand out with striking clarity. This is essential for revealing the delicate shells of planetary nebulae or the shock fronts in supernova remnants.\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\u003eRejecting Skyglow by Targeting the 500nm Wavelength\u003c\/h3\u003e\n      \u003cp\u003eThe filter's transmission is precisely centered at 500nm to align with the OIII emission lines. Its primary function is to block out common sources of light pollution, including mercury-vapor and sodium-vapor streetlights, as well as the natural skyglow caused by neutral oxygen emission in the atmosphere. This targeted rejection allows for deep-sky imaging even under moonlit or urban sky conditions.\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\u003eBuilding the Hubble Palette: The \"O\" in SHO Imaging\u003c\/h3\u003e\n      \u003cp\u003eFor astrophotographers, the Optolong OIII 6.5nm filter is a cornerstone of narrowband imaging. It represents the \"O\" in the \"SHO\" Hubble Palette, where it is combined with Hydrogen-alpha and Sulphur-II filters. This technique allows you to create false-color images with stunning detail and color separation, revealing scientific information about the chemical composition of targets like the Pillars of Creation in the Eagle Nebula (M16).\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\u003eIon-Assisted Coatings for Wavelength Stability\u003c\/h3\u003e\n      \u003cp\u003eOptolong utilizes an ion-assisted deposition coating process to ensure the filter's durability and optical precision. This advanced technique produces a hard, scratch-resistant surface and guarantees the central wavelength (CWL) remains stable, with no deviation due to temperature changes during an imaging session. This consistency is critical for maintaining sharp focus and reliable data acquisition over long exposures.\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 purpose of the Optolong OIII 6.5nm filter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe Optolong OIII 6.5nm filter is designed to isolate the light emitted by doubly-ionized oxygen (OIII) from astronomical objects. Its narrow \u003cstrong\u003e6.5nm bandpass\u003c\/strong\u003e dramatically increases contrast by blocking light pollution and natural skyglow, making it ideal for imaging faint emission nebulae, planetary nebulae, and supernova remnants.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Optolong OIII 6.5nm filter make nebulae appear brighter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo, narrowband filters do not increase an object's brightness. Instead, the Optolong OIII 6.5nm filter increases the \u003cstrong\u003econtrast\u003c\/strong\u003e between the nebula and the night sky. By selectively blocking out all light except the specific 500nm OIII wavelength, it makes the background sky much darker, which in turn makes the nebula's structure far more visible.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong OIII 6.5nm filter fit into a SHO (Hubble Palette) imaging setup?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe Optolong OIII 6.5nm filter is the \"O\" component in a standard SHO narrowband imaging set. Data captured with this filter is typically mapped to the green channel in image processing, alongside data from Hydrogen-alpha (red channel) and Sulphur-II (blue channel) filters. This combination creates the iconic, high-detail false-color images popularized by the Hubble Space Telescope.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow would the Optolong OIII 6.5nm filter perform on the Rosette Nebula (Caldwell 49) from a city?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe Rosette Nebula is rich in both Hydrogen-alpha and Oxygen-III. From a light-polluted city, the Optolong OIII 6.5nm filter would be essential for capturing the delicate structures within the nebula's central region. It would effectively cut through the urban skyglow, allowing you to record the faint OIII signal that would otherwise be completely washed out, revealing details in the excavated core of the nebula.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong OIII 6.5nm filter necessary for imaging the Pillars of Creation (M16)?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, it is a critical component for creating a classic Hubble Palette image of M16. While the pillars themselves are dense with Hydrogen-alpha and Sulphur-II, the surrounding nebulosity and the glowing edges of the pillars are illuminated by the intense radiation from young stars, causing them to emit strongly in OIII light. The Optolong OIII 6.5nm filter is required to capture this data and create the famous color separation and depth.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the Optolong OIII 6.5nm filter work with both monochrome and color cameras?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThis filter is designed primarily for use with \u003cstrong\u003emonochrome\u003c\/strong\u003e astronomy cameras. A monochrome sensor's higher sensitivity can take full advantage of the isolated wavelength. While it can be used with a one-shot-color (OSC) camera, the camera's Bayer matrix will only allow the blue and green pixels to detect the OIII signal, significantly reducing efficiency and resolution.\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 Options\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, 36mm Round Unmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":52941918765341,"sku":"OPT-11501","price":223.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":52941918798109,"sku":"OPT-11502","price":321.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":52941918830877,"sku":"OPT-11504","price":265.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-improved-OIII6-5nm-narrowband-filter-1_8f87788c-6f04-4840-9bab-e49eeb58426d.jpg?v=1789592379"},{"product_id":"optolong-cls-filter","title":"Optolong CLS Light Pollution Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eSuppresses common light pollution sources\u003c\/li\u003e\n\u003cli\u003eAverage transmission greater than 90% on key nebula emission lines\u003c\/li\u003e\n\u003cli\u003eBlocks light pollution lines with \u0026gt;99% efficiency\u003c\/li\u003e\n\u003cli\u003e1.85mm thick optical glass substrate\u003c\/li\u003e\n\u003cli\u003eλ\/4 transmitted wavefront and 30s parallelism\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong CLS Light Pollution Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong CLS (City Light Suppression) filter restores contrast to your deep-sky views by blocking over 99% of common artificial light sources. Built on a 1.85mm optical glass substrate, it maintains a λ\/4 transmitted wavefront for sharp images while delivering over 90% transmission of critical nebula emission lines like H-alpha and OIII. With 30s parallelism, the filter introduces no optical distortions, making it a powerful tool for visual observers and imagers using color cameras or unmodified DSLRs under suburban skies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eTargeted Light Pollution Suppression: \u0026gt;99% Blocking of Sodium \u0026amp; Mercury Lines\u003c\/h3\u003e\n\u003cp\u003eThe core function of the Optolong CLS is to surgically remove the wavelengths associated with common streetlights. It achieves greater than 99% blocking of mercury vapor, high-pressure sodium, and low-pressure sodium vapor lamp emissions. This aggressive rejection of unwanted light darkens the sky background significantly, allowing the faint signal from your target to stand out in much higher contrast.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eHigh-Transmission Broadband Design: \u0026gt;90% Pass-Through on Key Emission Lines\u003c\/h3\u003e\n\u003cp\u003eWhile blocking unwanted light, the CLS filter maintains an average transmission of over 90% for the most important deep-sky wavelengths. This wide passband includes hydrogen-alpha (656nm), hydrogen-beta (486nm), oxygen-III (496nm and 500nm), and sulfur-II (672nm). By preserving the light from these emission nebulae, the filter reveals more detail and structure in objects like the Orion Nebula (M42) or the Lagoon Nebula (M8) without significantly altering natural star colors.\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-Coated 1.85mm Glass: λ\/4 Wavefront and 30s Parallelism\u003c\/h3\u003e\n\u003cp\u003eOptolong constructs the CLS filter from a 1.85mm thick slab of fine optical glass, ensuring mechanical stability and optical purity. Ion-assisted deposition coatings provide durability and prevent the central wavelength from shifting with temperature changes. The filter is polished to a transmitted wavefront of λ\/4 and a parallelism of 30 arcseconds, guaranteeing that it will not degrade the resolution of your telescope's optics.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOptolong CLS vs. UHC Filters: Choosing the Right Tool for Your Sky\u003c\/h3\u003e\n\u003cp\u003eThe CLS is often compared to Ultra High Contrast (UHC) filters. The primary difference is the width of the passband.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptolong CLS Filter:\u003c\/strong\u003e Features a wider passband, making it more effective in mild to moderate light pollution. It preserves more natural star color and is a better general-purpose filter for a mix of objects, including reflection nebulae and star clusters.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUHC Filter:\u003c\/strong\u003e Has a narrower passband, primarily focused on the H-beta and OIII lines. This provides more aggressive contrast on emission nebulae but can dim stars more significantly. It is often preferred for darker sites or areas with more severe light pollution where maximum rejection is needed.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main difference between the Optolong CLS and a UHC filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003eOptolong CLS filter\u003c\/strong\u003e has a wider bandpass, making it a \"broadband\" filter ideal for mild to moderate light pollution. It passes more of the visible spectrum, resulting in more natural star colors. A UHC filter is a \"narrowband\" filter with a tighter passband, offering higher contrast on emission nebulae but at the cost of dimming stars more, making it better suited for more heavily light-polluted skies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong CLS filter for imaging galaxies like Andromeda (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, but with limitations. Galaxies are broadband targets, meaning they emit light across the entire visible spectrum. The \u003cstrong\u003eOptolong CLS filter\u003c\/strong\u003e will increase the contrast between the galaxy and the skyglow, but it will also block some of the galaxy's own light. It can help bring out H-II regions in the spiral arms but may reduce the overall brightness of the galactic core.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Optolong CLS filter perform on 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\u003eThe \u003cstrong\u003eOptolong CLS filter\u003c\/strong\u003e is an excellent choice for this scenario. M42 is rich in hydrogen-alpha and oxygen-III emissions, which the filter transmits with over 90% efficiency. In your 8\" SCT, the filter will dramatically darken the suburban sky background, making the faint outer loops of the nebula visible and enhancing the contrast and detail within the Trapezium region.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong CLS filter suitable for an unmodified DSLR camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the \u003cstrong\u003eOptolong CLS filter\u003c\/strong\u003e is designed to work very well with color CMOS\/CCD cameras and unmodified DSLRs. Its passband includes the critical 656nm H-alpha line, which standard DSLRs are less sensitive to but still capture. The filter helps isolate this important wavelength from light pollution, improving the signal in your images.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the Optolong CLS filter make nebulae look brighter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this is a common misconception. No filter can increase an object's actual brightness. The \u003cstrong\u003eOptolong CLS filter\u003c\/strong\u003e works by increasing the *contrast* between the nebula and the night sky. It achieves this by selectively blocking light pollution, which makes the background darker, thereby making the nebula easier to see against it.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy does my Optolong CLS filter look like a mirror and change colors?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis is normal for an interference filter like the \u003cstrong\u003eOptolong CLS\u003c\/strong\u003e. The highly reflective appearance is due to the dielectric coatings that are precisely layered to reject specific wavelengths of light. The color will appear to shift depending on the viewing angle and ambient light, which is a sign that the coatings are functioning as designed.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWARNING: Can I use the Optolong CLS filter for observing the Sun?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eAbsolutely not.\u003c\/strong\u003e The Optolong CLS filter is NOT a solar filter and is not designed for sun observation. Looking at the Sun with this filter, or any filter not explicitly designed for safe solar viewing, will cause immediate and permanent blindness.\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\u003eBroadband Light Pollution Suppression (CLS)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eOptical glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eThickness\u003c\/td\u003e\n\u003ctd\u003e1.85mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAverage Transmission\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Range\u003c\/td\u003e\n\u003ctd\u003e400-700nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Depth\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;99% on light pollution lines\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront\u003c\/td\u003e\n\u003ctd\u003eλ\/4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30s\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eOptolong CLS Light Pollution Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eProtective 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\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":52941921288477,"sku":"OPT-11801","price":77.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":52941921321245,"sku":"OPT-11802","price":119.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-CLS-City-Light-Suppression-broadband-filter-is-designed-to-improve-the-visibility-of-various-deepsky-objects-1_1622ccd9-042b-4aec-b31c-a974b2ff5095.jpg?v=1789592400"},{"product_id":"optolong-cls-ccd-filter","title":"Optolong CLS-CCD Light Pollution Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eBlocks \u0026gt;99% of primary light pollution emission lines\u003c\/li\u003e\n\u003cli\u003eAchieves \u0026gt;90% average transmission on key nebula wavelengths\u003c\/li\u003e\n\u003cli\u003eIntegrated 300-1100nm UV\/IR cut filter for color cameras\u003c\/li\u003e\n\u003cli\u003eλ\/4 transmitted wavefront and 30s parallelism for sharp stars\u003c\/li\u003e\n\u003cli\u003e1.85mm thick optical glass substrate\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong CLS-CCD Light Pollution Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong CLS-CCD Light Pollution Filter is engineered to reclaim contrast in your astrophotos by blocking over 99% of common light pollution sources while maintaining an average transmission greater than 90% on critical nebula emission lines. Its integrated 300-1100nm blocking range makes it a single-filter solution for color CCD and modified DSLR cameras, eliminating star bloat from infrared without needing a separate IR-cut filter. The 1.85mm optical glass substrate is polished to a λ\/4 transmitted wavefront, ensuring your system's resolution is not compromised.\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 \u0026gt;99% of Sodium and Mercury Vapor Lines\u003c\/h3\u003e\n\u003cp\u003eThis filter's primary function is to surgically remove the wavelengths associated with urban skyglow. It achieves a blocking depth of over 99% for mercury vapor, high-pressure sodium, and low-pressure sodium vapor lamps—the most common sources of artificial light pollution. By rejecting this unwanted light, the background sky in your images becomes significantly darker, allowing the faint, complex structures of nebulae to 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\u003eOver 90% Transmission on H-alpha, OIII, and SII\u003c\/h3\u003e\n\u003cp\u003eWhile aggressively blocking pollutants, the CLS-CCD maintains an average transmission rate (Tave) of over 90% across the most important emission lines for deep-sky objects. This high throughput applies to hydrogen-alpha (656nm), oxygen-III (496nm and 500nm), hydrogen-beta (486nm), and sulfur-II (672nm). The result is vibrant, high-contrast images of emission nebulae, planetary nebulae, and supernova remnants, with their natural colors preserved.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe CCD Advantage: Integrated 300-1100nm IR\/UV Cut for Color Sensors\u003c\/h3\u003e\n\u003cp\u003eThe \"CCD\" in the name signifies a critical feature: a built-in UV and IR cut filter covering a wide 300-1100nm range. Many color astronomy cameras and modified DSLRs have sensors that are sensitive to infrared light, which can cause bloated, unfocused stars if not filtered out. The CLS-CCD eliminates the need for a separate L-filter (luminance\/IR-cut), simplifying your imaging train and ensuring sharp, tight stars across the frame.\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\u003eCLS-CCD vs. Standard CLS: Why IR Cut Matters\u003c\/h3\u003e\n\u003cp\u003eThe key difference between the Optolong CLS-CCD and the standard visual CLS filter is the infrared blocking. While both filters suppress the same light pollution lines, the standard CLS allows infrared light to pass through. This makes it suitable for visual use or for monochrome cameras shooting with a separate filter wheel.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eChoose the CLS-CCD if:\u003c\/strong\u003e You use a one-shot-color (OSC) camera, a color CCD, or a modified DSLR. The integrated IR-cut is essential for preventing star bloat and achieving correct color balance without an extra filter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eChoose the standard CLS if:\u003c\/strong\u003e You are a visual observer or use a monochrome camera with a separate IR-cut filter in your luminance (L) channel.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main difference between the Optolong CLS-CCD and the standard CLS filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003eOptolong CLS-CCD\u003c\/strong\u003e includes an integrated IR\/UV cut filter that blocks wavelengths from 300-1100nm. This is essential for color cameras (OSC\/DSLR) to prevent star bloat from infrared light. The standard CLS filter does not block IR and is intended more for visual use or monochrome imaging setups that use a separate luminance filter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong CLS-CCD filter for visual observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile you can, it's not ideal. The filter's transmission characteristics are optimized for the response of a digital sensor. For visual use, the standard Optolong CLS filter typically provides a brighter, more natural-looking view through the eyepiece.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Optolong CLS-CCD filter work with my unmodified DSLR camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, but with limited effectiveness for certain objects. An unmodified DSLR has its own internal filter that blocks most of the deep red H-alpha light (656nm). The CLS-CCD will still improve contrast by blocking skyglow, but to capture the rich red nebulosity in objects like the North America Nebula (NGC 7000), a \"modified\" DSLR with the stock filter removed is required.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the CLS-CCD filter affect imaging the Orion Nebula (M42) from a city?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFor an object like the Orion Nebula (M42), the CLS-CCD filter will dramatically improve your results from a light-polluted area. It will darken the sky background, significantly increasing the contrast of the glowing hydrogen and oxygen gases that make up the nebula. This allows you to capture much more of the faint, extended nebulosity without the image being 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 the Optolong CLS-CCD a good choice for imaging galaxies like Andromeda (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt's a trade-off. Galaxies like the Andromeda Galaxy (M31) are broadband objects, meaning they emit light across the entire visible spectrum, similar to stars. A light pollution filter like the CLS-CCD will block some of the galaxy's own light along with the skyglow. While it can help darken the background, it may also alter the galaxy's natural color balance. For galaxies, less aggressive filters or simply capturing more data from a dark site is often the preferred approach.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong CLS-CCD filter to look at the Sun?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eAbsolutely not.\u003c\/strong\u003e The Optolong CLS-CCD filter is \u003cstrong\u003eNOT\u003c\/strong\u003e a solar filter and is not designed for sun observation. Looking at the Sun with this filter, or any filter not explicitly designed for safe solar viewing, will cause immediate and permanent eye damage, including blindness. Always use a certified safe solar filter that covers the entire front aperture of your telescope.\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\u003eBroadband Light Pollution (LP) Filter with IR\/UV Cut\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Material\u003c\/td\u003e\n\u003ctd\u003eOptical glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Thickness\u003c\/td\u003e\n\u003ctd\u003e1.85mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAverage Transmission\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Range\u003c\/td\u003e\n\u003ctd\u003e300-1100nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLight Pollution Blocking\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;99%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront RMS\u003c\/td\u003e\n\u003ctd\u003eλ\/4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30s\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":52941923090717,"sku":"OPT-11901","price":133.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":52941923123485,"sku":"OPT-11902","price":223.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-The-CLS-CCD-broadband-filter-is-designed-to-improve-the-visibility-of-various-deepsky-objects-1_19932723-0c05-473f-91d2-3b4f840aeed2.jpg?v=1789592410"},{"product_id":"optolong-clear-focusing-filter","title":"Optolong Clear Focusing Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eAchieve Critical Focus with Dim Stars\u003c\/li\u003e\n\u003cli\u003eTransmission \u0026gt;98.5% Across the Visible Spectrum\u003c\/li\u003e\n\u003cli\u003eλ\/4 Transmitted Wavefront for Image Integrity\u003c\/li\u003e\n\u003cli\u003eParfocal with Other 1.85mm Optolong Filters\u003c\/li\u003e\n\u003cli\u003eFunctions as a High-Quality Sensor Dust Shield\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section-center\"\u003e\n      \u003ch2\u003eOptolong Clear Focusing Filter\u003c\/h2\u003e\n      \u003cp\u003eThe Optolong Clear Focusing Filter is a dedicated utility filter designed to solve one of astrophotography's most persistent challenges: achieving perfect focus with dim stars. By passing over 98.5% of visible light, this filter ensures your focusing star is as bright as possible, a critical advantage when narrowband or light pollution filters would otherwise render it nearly invisible. Constructed from B270 glass with a transmitted wavefront of λ\/4 and a thickness of 1.85mm, it maintains the optical path's integrity, allowing you to focus with confidence before swapping to your imaging filter.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-danger\"\u003e\n      \u003cdiv class=\"DAV-section-center\"\u003e\n          \u003ch3\u003e\n\u003csvg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 512 512\" style=\"width: 20px; height: 20px; fill: currentColor; margin-right: 8px; vertical-align: text-bottom;\"\u003e\u003cpath d=\"M256 32c14.2 0 27.3 7.5 34.5 19.8l216 368c7.3 12.4 7.3 27.7 .2 40.1S486.3 480 472 480H40c-14.3 0-27.6-7.7-34.7-20.1s-7-27.8 .2-40.1l216-368C228.7 39.5 241.8 32 256 32zm0 128c-13.3 0-24 10.7-24 24V296c0 13.3 10.7 24 24 24s24-10.7 24-24V184c0-13.3-10.7-24-24-24zm32 224a32 32 0 1 0 -64 0 32 32 0 1 0 64 0z\"\u003e\u003c\/path\u003e\u003c\/svg\u003eCritical Safety Warning: Not for Solar Use\u003c\/h3\u003e\n          \u003cp\u003eThis filter is \u003cstrong\u003eNOT\u003c\/strong\u003e designed for solar observation. Looking at the Sun with this filter, or any filter not explicitly certified for safe solar viewing, will cause immediate and irreversible eye damage, including permanent blindness. Do not point your telescope at the Sun with this filter attached.\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\u003eAchieve Critical Focus with \u0026gt;98.5% Transmission\u003c\/h3\u003e\n      \u003cp\u003eNarrowband and aggressive light pollution filters drastically dim incoming starlight, making it difficult for autofocus routines to lock on or for you to judge manual focus accurately. The Optolong Clear Filter solves this by passing more than 98.5% of light across the entire 420-680nm visible spectrum. You simply use this filter to achieve a sharp, bright focus on a star, then swap it for your narrowband or LRGB filter to begin imaging, knowing your focus is already set.\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\u003eParfocal and Protective with λ\/4 Wavefront Flatness\u003c\/h3\u003e\n      \u003cp\u003eA focusing aid is useless if it degrades your image or shifts the focal point. The Optolong Clear Filter is made from B270 substrate polished to a λ\/4 transmitted wavefront with 30s parallelism, ensuring it won't introduce aberrations. Its 1.85mm thickness makes it parfocal with other Optolong filters of the same thickness, minimizing the need to refocus after a filter change. It also serves as an excellent dust shield, protecting your camera sensor or reducer optics from dust during long imaging sessions.\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\"\u003eWhy do I need the Optolong Clear Focusing Filter? Can't I just focus without a filter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eWhile you can focus without a filter, adding a narrowband or LRGB filter into the optical path will slightly shift the focal point. The Optolong Clear Focusing Filter has a thickness of \u003cstrong\u003e1.85mm\u003c\/strong\u003e, designed to be parfocal with other Optolong filters. By focusing with this filter first, you ensure the focal point is correctly set for when you swap to your imaging filter, saving time and guaranteeing sharp results.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong Clear Filter the same as a Luminance (L) filter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo. A Luminance filter is an imaging filter with specific UV and IR blocking characteristics. The Optolong Clear Filter is a utility filter designed purely for focusing. It passes a wider band of light (\u003cstrong\u003e\u0026gt;98.5%\u003c\/strong\u003e from 420-680nm) to maximize star brightness for focusing software and visual confirmation. It is not intended for capturing final image data.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong Clear Filter help when imaging the Horsehead Nebula (B33) with a narrowband filter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eImaging Barnard 33 requires a strong Hydrogen-alpha filter, which blocks almost all starlight except for a single wavelength. This makes focusing stars extremely dim and difficult. With the Optolong Clear Filter, you can select a nearby bright star like Alnitak, achieve perfect focus using the full visible spectrum, lock your focuser, and then switch to your Ha filter to capture the faint nebulosity without struggling to see the dim, red-only star.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Optolong Clear Filter improve focusing with my modified DSLR and f\/5 Newtonian?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes. A modified DSLR is more sensitive to a broader spectrum of light, and this filter's \u003cstrong\u003e\u0026gt;98.5%\u003c\/strong\u003e transmission takes full advantage of that. In an f\/5 Newtonian, stars will be bright and sharp through the Clear Filter, allowing your camera's live view or focusing software to achieve a much more accurate focus than with a light pollution or narrowband filter installed.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eCan I leave the Optolong Clear Filter in the optical train as a dust shield?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eAbsolutely. With its high-quality \u003cstrong\u003eB270\u003c\/strong\u003e substrate and \u003cstrong\u003eλ\/4\u003c\/strong\u003e wavefront, it will not degrade your image quality. It acts as an effective barrier, preventing dust from settling on your camera sensor or reducer optics during a long imaging night.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong Clear Filter for solar viewing?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003e\u003cstrong\u003eNO. ABSOLUTELY NOT.\u003c\/strong\u003e This filter provides no protection from the Sun's harmful radiation. Using it for solar observation will cause instant and permanent blindness. Only use filters specifically designed and certified for safe solar observation.\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\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eB270\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eThickness\u003c\/td\u003e\n\u003ctd\u003e1.85mm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eAverage Transmission\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;98.5% (420-680nm)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront RMS\u003c\/td\u003e\n\u003ctd\u003eλ\/4\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30s\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cul class=\"DAV-grid\"\u003e\n    \u003cli class=\"DAV-grid-item\"\u003e\n      \u003cdiv\u003e\n        \u003cp class=\"DAV-item-title\"\u003eOptolong Clear Focusing Filter (Selected Size)\u003c\/p\u003e\n        \u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":52941924565277,"sku":"OPT-12401","price":34.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":52941924598045,"sku":"OPT-12402","price":42.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-Clear-focusing-filter-is-designed-to-highly-pass-the-visible-spectral-region-420-680nm-at-98-5-transmission-1_d5f8835e-290b-416b-b60e-680f79a67a1a.jpg?v=1789592420"},{"product_id":"optolong-oiii-18nm-filter","title":"Optolong OIII 18nm Nebula Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e18nm Bandpass Centered on OIII Emission Lines (500nm)\u003c\/li\u003e\n\u003cli\u003eGreater than 80% Average Light Transmission (Tave)\u003c\/li\u003e\n\u003cli\u003eBlocks \u0026gt;99% of Major Light Pollution Lines\u003c\/li\u003e\n\u003cli\u003e1.85mm Thick Optical Glass Substrate\u003c\/li\u003e\n\u003cli\u003eλ\/4 Transmitted Wavefront and 60\/40 Surface Quality\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong OIII 18nm Nebula Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong OIII 18nm Nebula Filter isolates the critical 500nm emission lines from planetary nebulae and supernova remnants with its focused 18nm bandpass. By achieving over 80% average transmission at these key wavelengths while blocking more than 99% of light pollution within its 400-700nm range, this filter dramatically increases contrast. The optically flat λ\/4 wavefront ensures your telescope's resolution is preserved, delivering sharp, high-contrast views even from suburban skies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eIsolating Nebulae: The 18nm OIII Passband\u003c\/h3\u003e\n\u003cp\u003eThis filter is engineered to transmit a specific 18nm sliver of the blue-green spectrum, centered at 500nm. This window precisely captures the light from doubly ionized oxygen (OIII), the primary emission from targets like the Dumbbell Nebula (M27) and the Veil Nebula (NGC 6960). By isolating this light, the filter renders these faint structures visible against a darkened 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\u003eHigh-Contrast Views from Blocking \u0026gt;99% of Light Pollution\u003c\/h3\u003e\n\u003cp\u003eThe core function of the Optolong OIII filter is to improve contrast by aggressively rejecting unwanted light. It blocks over 99% of the primary wavelengths associated with mercury vapor, sodium vapor streetlights, and natural skyglow. This doesn't make the nebula brighter in absolute terms; it darkens the sky so severely that the nebula's faint details stand out in stark relief, transforming a washed-out view into a well-defined object.\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 Optics: λ\/4 Wavefront and 60\/40 Surface Quality\u003c\/h3\u003e\n\u003cp\u003eA filter should only reveal detail, not degrade it. Optolong builds this filter on a 1.85mm optical glass substrate polished to a 60\/40 surface quality and a transmitted wavefront of λ\/4 or better. This level of optical precision ensures that the filter will not introduce aberrations or soften the image, preserving the sharpness delivered by your telescope's main optics. The multi-layer, ion-assisted coatings provide durability and resistance to scratching while ensuring wavelength stability regardless of temperature.\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\u003e18nm vs. Narrower OIII Filters: The Visual Advantage\u003c\/h3\u003e\n\u003cp\u003eWhile astrophotographers often use ultra-narrow 3nm or 7nm OIII filters, the 18nm bandpass of this Optolong filter is intentionally wider for visual astronomy. This wider window allows more photons to reach your eye, resulting in a significantly brighter and more comfortable view through the eyepiece.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrighter Image:\u003c\/strong\u003e The 18nm design prevents the image from becoming overly dim, which can happen with narrower filters, especially in telescopes under 8 inches of aperture.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaintains Contrast:\u003c\/strong\u003e It still provides a dramatic contrast boost, making it an ideal middle ground between a broadband UHC filter and a specialized imaging filter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBetter for More Objects:\u003c\/strong\u003e The increased brightness makes it effective on a wider range of emission nebulae, not just the very brightest planetary nebulae.\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 objects work best with the Optolong 18nm OIII filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Optolong 18nm OIII filter excels on nebulae rich in ionized oxygen. It is most effective on \u003cstrong\u003eplanetary nebulae\u003c\/strong\u003e like the Ring Nebula (M57) and the Dumbbell Nebula (M27), and \u003cstrong\u003esupernova remnants\u003c\/strong\u003e such as the Veil Nebula complex (NGC 6960\/6992). It can also enhance portions of larger emission nebulae like the Lagoon Nebula (M8).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Optolong 18nm OIII filter make nebulae brighter from my city?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, a narrowband filter cannot make an object intrinsically brighter. Its purpose is to \u003cstrong\u003eincrease contrast\u003c\/strong\u003e. It works by blocking over 99% of common light pollution sources, which makes the sky background appear much darker. This allows the faint light from the nebula to stand out more clearly, making it easier to see, but the nebula's actual brightness remains unchanged.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Optolong 18nm OIII filter improve my view of the Dumbbell Nebula (M27) in my 8\" Dobsonian?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIn an 8\" Dobsonian, the Optolong 18nm OIII filter will make a dramatic difference on M27, especially from suburban skies. The sky background will darken significantly, causing the nebula's classic \"apple core\" shape to pop with well-defined edges. You may also begin to see the fainter lobes and internal structures that are often lost in the skyglow without a filter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 18nm OIII filter too aggressive for viewing the Orion Nebula (M42) with a 4\" refractor?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFor a very bright object like the Orion Nebula (M42), an 18nm OIII filter is an excellent choice. While M42 is bright enough to see without a filter, the OIII filter will isolate the intricate, wispy details in the nebula's core and wings, revealing structure that is normally overwhelmed by the nebula's own brightness. The 18nm bandpass is wide enough that the view in a 4\" scope will remain bright and engaging.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy choose an 18nm OIII filter instead of a narrower 7nm version for visual observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe 18nm bandpass is specifically optimized for the human eye. Narrower filters, like 7nm or 3nm versions, are designed for CCD\/CMOS sensors and can produce an image that is too dim for satisfying visual use, particularly in smaller telescopes. The 18nm filter provides a powerful contrast boost while maintaining enough image brightness for a comfortable and detailed view.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong 18nm OIII filter for astrophotography?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile it is primarily designed for visual use, you can use the 18nm OIII for astrophotography, especially with one-shot color cameras from light-polluted areas. It provides a stronger signal and more natural star shapes than ultra-narrowband filters. However, for serious narrowband imaging from any location, a dedicated 7nm, 5nm, or 3nm OIII filter will provide higher contrast and better rejection of moonlight.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandpass\u003c\/td\u003e\n\u003ctd\u003e18nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCentral Wavelength\u003c\/td\u003e\n\u003ctd\u003e500nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Material\u003c\/td\u003e\n\u003ctd\u003eOptical Glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Thickness\u003c\/td\u003e\n\u003ctd\u003e1.85mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAverage Transmission\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;80%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Range\u003c\/td\u003e\n\u003ctd\u003e400-700nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Depth\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;99% of light pollution lines\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront RMS\u003c\/td\u003e\n\u003ctd\u003eλ\/4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30s\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eOptolong OIII 18nm Nebula 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 Plastic Case\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":52941926269213,"sku":"OPT-12701","price":111.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":52941926301981,"sku":"OPT-12702","price":151.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-narrowband-OIII-filter-is-designed-for-nebula-observation-allowing-18nm-bandwidth-of-light-centered-on-a-wavelength-of-500nm-through-1_d6a50468-3847-45e5-a0b6-0ecabb379087.jpg?v=1789592430"},{"product_id":"optolong-night-sky-h-alpha-filter-ir-pass-630nm","title":"Optolong Night Sky H-Alpha IR Pass Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003ePasses Infrared Light \u0026gt;650nm\u003c\/li\u003e\n\u003cli\u003eBlocks Visible Light from 300-570nm\u003c\/li\u003e\n\u003cli\u003eAverage Transmission \u0026gt;90%\u003c\/li\u003e\n\u003cli\u003e1.85mm Thick Optical Glass Substrate\u003c\/li\u003e\n\u003cli\u003eλ\/4 Transmitted Wavefront\u003c\/li\u003e\n\u003cli\u003eAvailable in 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\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong Night Sky H-Alpha IR Pass Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong Night Sky H-Alpha IR Pass Filter is a specialized tool for planetary imagers seeking to overcome atmospheric turbulence. By aggressively blocking visible light in the 300-570nm range and passing infrared wavelengths with over 90% average transmission, this filter isolates the steadiest light for a sharper luminance channel. The filter is built on a 1.85mm optical glass substrate with a λ\/4 transmitted wavefront, ensuring it preserves the detail captured by your telescope.\u003c\/p\u003e\n\u003cdiv class=\"DAV-warning-box\"\u003e\n\u003csvg viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M256 32c14.2 0 27.3 7.5 34.5 19.8l216 368c7.3 12.4 7.3 27.7 .2 40.1S486.3 480 472 480H40c-14.3 0-27.6-7.7-34.7-20.1s-7-27.8 .2-40.1l216-368C228.7 39.5 241.8 32 256 32zm0 128c-13.3 0-24 10.7-24 24V296c0 13.3 10.7 24 24 24s24-10.7 24-24V184c0-13.3-10.7-24-24-24zm32 224a32 32 0 1 0 -64 0 32 32 0 1 0 64 0z\" fill=\"#D70000\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cp\u003e\u003cstrong\u003eWARNING:\u003c\/strong\u003e This filter is NOT for solar observation. DO NOT look at the Sun with this or any Optolong filter not explicitly designed for solar viewing. Failure to observe this warning will result in permanent blindness.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eSharpening Luminance Beyond 640nm for Planetary Imaging\u003c\/h3\u003e\n\u003cp\u003eAtmospheric seeing, the turbulence that blurs celestial objects, has a greater effect on shorter wavelengths of light like blue and green. The Optolong IR Pass filter defeats this by acting as a bouncer at the door; it completely blocks light below 570nm. It begins passing light around 640nm and achieves over 95% transmission beyond 650nm, capturing a signal composed of much steadier photons. \u003c\/p\u003e\n\u003cp\u003eWhen used as a replacement for a standard luminance (L) filter in an LRGB workflow, this IR-pass signal produces a dramatically sharper monochrome image. When you combine this superior IR luminance with your color RGB data, the final composite image reveals finer details in Jupiter's cloud bands, the Cassini Division in Saturn's rings, and subtle features on Mars.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eλ\/4 Wavefront and 1.85mm Substrate for Optical Purity\u003c\/h3\u003e\n\u003cp\u003eA filter is useless if it degrades the image your telescope produces. Optolong ensures optical integrity by using a high-quality glass substrate polished to a transmitted wavefront of λ\/4 or better. This level of precision means the filter will not introduce aberrations or distortions into the light path.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eParfocal Design:\u003c\/strong\u003e The \u003cstrong\u003e1.85mm\u003c\/strong\u003e substrate thickness is designed to be nearly parfocal with other common filters, minimizing the need to refocus when switching between filters in a wheel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDurable Coatings:\u003c\/strong\u003e Ion-assisted deposition coatings provide resistance to scratching and ensure the filter's central wavelength (CWL) remains stable regardless of temperature changes during an imaging session.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturing Precision:\u003c\/strong\u003e A surface quality of \u003cstrong\u003e60\/40\u003c\/strong\u003e and parallelism of \u003cstrong\u003e30 arcseconds\u003c\/strong\u003e guarantee a clean, artifact-free image without internal reflections.\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\u003eIR Pass vs. Standard Luminance: A Specialist Filter for Seeing\u003c\/h3\u003e\n\u003cp\u003eWhile a standard luminance filter aims to capture the entire visible spectrum for maximum brightness, it also captures all the atmospheric blurring that comes with it. The Optolong H-Alpha IR Pass filter takes a different approach, prioritizing sharpness over total brightness by selectively choosing which light to record.\u003c\/p\u003e\n\u003cp\u003eA standard L-filter is a generalist, excellent for deep-sky objects where collecting every photon matters most. This IR Pass filter is a specialist. It intentionally discards the unsteady visible-spectrum light to create a superior luminance foundation for planetary IR-LRGB imaging, delivering a level of detail that a standard L-filter cannot achieve on nights of average or poor seeing.\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\"\u003eCan I use the Optolong H-Alpha IR Pass filter to view the Sun?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eAbsolutely not.\u003c\/strong\u003e This filter is designed for night sky imaging and provides no protection from the Sun's harmful radiation. Looking at the Sun with this filter, even for a moment, will cause immediate and permanent eye damage, including blindness. Only use filters specifically designed and certified for safe solar observation.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong IR Pass filter improve my images of Jupiter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eJupiter's low altitude for northern hemisphere observers often means looking through turbulent air. This filter cuts through that \"seeing\" by blocking the most easily scattered blue and green light (\u003cstrong\u003e300-570nm\u003c\/strong\u003e) and only passing the more stable, longer red and infrared wavelengths. The result is a much sharper black-and-white luminance image that can be combined with RGB data to show fine details in the Great Red Spot and intricate swirls in the cloud belts.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong H-Alpha IR Pass filter useful for deep-sky imaging?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eGenerally, no. This filter is a specialist tool for planetary, lunar, and solar system imaging. For deep-sky objects like galaxies and nebulae, you want to collect as much light as possible across the visible spectrum. A standard Luminance (L) filter or narrowband filters (H-alpha, OIII, SII) are the correct tools for deep-sky astrophotography.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use this Optolong filter with my one-shot-color (OSC) camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile designed for monochrome cameras to create a luminance channel, you can use it with a color camera. By enabling monochrome mode (or debayering the final image as black-and-white), you can capture a sharp IR-only image. However, its primary benefit is realized when combined with separate RGB data in an IR-LRGB composite, a technique best suited for monochrome cameras and filter wheels.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill I need to refocus my 8\" f\/10 SCT when switching to the Optolong 1.85mm IR Pass filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e1.85mm\u003c\/strong\u003e thickness is designed to be nearly parfocal with many other brands of 1.25\" and 2\" filters. While you should always check critical focus, the amount of adjustment needed will be minimal, if any. This is a significant advantage when using a filter wheel, as it saves time and prevents you from losing your target while refocusing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is this filter called \"H-Alpha\" if it's an IR Pass filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe name can be confusing. The filter's transmission starts to ramp up near the Hydrogen-alpha wavelength (656nm), so it passes H-alpha light and everything with a longer wavelength. However, its primary function isn't narrowband imaging but rather to serve as a very long-pass filter that uses the infrared spectrum to stabilize planetary images against atmospheric seeing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Material\u003c\/td\u003e\n\u003ctd\u003eOptical glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thickness\u003c\/td\u003e\n\u003ctd\u003e1.85mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAverage Transmission\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Range\u003c\/td\u003e\n\u003ctd\u003e300-570nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront RMS\u003c\/td\u003e\n\u003ctd\u003eλ\/4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30 arcseconds\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eOptolong Night Sky H-Alpha IR Pass Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eProtective Plastic Case\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":52941927121181,"sku":"OPT-12801","price":111.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":52941927153949,"sku":"OPT-12802","price":167.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-Night-Sky-H-Alpha-filter-IR-Pass-650nm-with-50-transition-from-blocking-to-passing-at-about-640nm-and-95-1_e2f058c9-b594-4cd2-a48c-cf16875a7fc1.jpg?v=1789592440"},{"product_id":"optolong-lrgb-h-alpha-7nm-filter-set-5-pcs","title":"Optolong LRGB + H-Alpha 7nm Filter Set","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eComplete 5-Filter LRGB and H-Alpha Set\u003c\/li\u003e\n\u003cli\u003e7nm H-Alpha Filter Centered at 656.3nm\u003c\/li\u003e\n\u003cli\u003eBlocks 589nm Sodium Light Pollution Line\u003c\/li\u003e\n\u003cli\u003eHigh Transmission for Natural Color Balance\u003c\/li\u003e\n\u003cli\u003eAvailable in 1.25\", 2\", and 36mm 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\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong LRGB + H-Alpha 7nm Filter Set\u003c\/h2\u003e\n\u003cp\u003eThis 5-filter Optolong LRGB + H-Alpha 7nm Filter Set provides a complete solution for monochrome deep-sky imaging, combining four high-contrast broadband filters with a narrow 7nm Hydrogen-Alpha filter centered at 656.3nm. The LRGB filters are engineered with a spectral gap to block the primary sodium light pollution line at 589nm, ensuring superior color separation on galaxies and star clusters. The included 7nm H-Alpha filter isolates critical emission nebula structures, providing the essential data needed to create deeply detailed composite images from any location.\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 4-Filter LRGB System for Broadband Color\u003c\/h3\u003e\n\u003cp\u003eThe core of this set is the Luminance, Red, Green, and Blue filter quartet, designed for maximum contrast and sharp color differentiation. The OIII emission lines are passed through both the blue and green filters, allowing for high-efficiency capture of planetary nebulae and supernova remnants with natural, balanced color. Extremely high gradients between the passbands ensure that data from each channel is cleanly separated for easier 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\u003eSuppressing City Glow: The 589nm Sodium Line Block\u003c\/h3\u003e\n\u003cp\u003eA key feature of the Optolong LRGB design is the deliberate gap between the green and red filters' transmission windows. This gap is precisely engineered to block the prominent sodium light pollution line at 589nm. By rejecting this common source of urban skyglow, the filters significantly improve color balance and saturation, allowing you to capture cleaner raw data even from suburban skies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe 7nm, 656.3nm H-Alpha Filter: Isolating Emission Nebulae\u003c\/h3\u003e\n\u003cp\u003eThe fifth filter in the set is a 7nm narrowband H-Alpha filter centered on the 656.3nm wavelength. This filter isolates the most common emission signal in the universe, dramatically increasing the contrast of hydrogen-rich targets like the Orion Nebula (M42) or the North American Nebula (NGC 7000). It aggressively suppresses starlight and background light pollution, revealing faint, intricate nebulosity that is invisible to broadband filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eLRGB+Ha vs. LRGB-Only: A 5-Filter Imaging Workflow\u003c\/h3\u003e\n\u003cp\u003eWhile an LRGB set is sufficient for broadband targets like galaxies and star clusters, the addition of the H-Alpha filter unlocks a new level of detail and creativity. For emission nebulae, you can substitute the Red channel data with the H-Alpha data for a dramatic \"HaRGB\" composite. For galaxies with active star-forming regions, like the Triangulum Galaxy (M33), you can blend the H-Alpha data into the Luminance or Red channels to make the HII regions pop against the stellar background, a technique not possible with a 4-filter set alone.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I use the H-Alpha filter in the Optolong LRGB+Ha set?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe H-Alpha filter can be used in several ways. You can capture it as a separate channel and blend it into your final LRGB image to enhance red nebulosity. A common technique is to substitute the data from the Red filter with your H-Alpha data to create a high-contrast HaRGB image, or to add it to the Luminance channel for a sharper, more detailed final result.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the 589nm block in this Optolong set eliminate all light pollution?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, but it is highly effective against a primary source. The gap between the green and red filters specifically targets sodium vapor lamps, which are a major component of urban skyglow. While it won't block modern LED lighting, it significantly improves color balance and contrast compared to filters without this feature, especially from older city lighting.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong 7nm H-Alpha filter suitable for very fast telescopes?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, Optolong filters are designed to minimize band-shifting with faster optical systems. While all interference filters experience some degree of shift, the \u003cstrong\u003e7nm bandpass\u003c\/strong\u003e is wide enough to remain effective on most common amateur telescopes, including f\/4 and f\/5 systems, without significant signal loss.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use this Optolong filter set with a color camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis set is designed for \u003cstrong\u003emonochrome cameras\u003c\/strong\u003e. A monochrome sensor allows you to capture data through each filter separately (L, R, G, B, Ha) and combine them during processing for a full-color image. A color camera already has a red, green, and blue filter array built into its sensor, making these filters redundant and ineffective.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eFor a target like the Andromeda Galaxy (M31), is the H-Alpha filter from the Optolong set useful?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. While the Andromeda Galaxy is primarily a broadband target, its spiral arms contain numerous star-forming HII regions that glow in H-Alpha light. Capturing data with the \u003cstrong\u003e7nm H-Alpha filter\u003c\/strong\u003e and blending it into your LRGB data will make these pink and red knots of nebulosity stand out dramatically, adding depth and scientific detail to your final image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow should I approach imaging the Pelican Nebula (IC 5070) with this Optolong LRGB+Ha set?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Pelican Nebula is an emission nebula rich in Hydrogen-Alpha. For this target, you should dedicate most of your imaging time to the \u003cstrong\u003e7nm H-Alpha filter\u003c\/strong\u003e to capture the faint structures and contrast. Use the L, R, G, and B filters primarily to capture star colors, then combine all five channels in processing. You can use the H-Alpha data as a detailed layer for your red channel or as a synthetic luminance.\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\u003eSet Contents\u003c\/td\u003e\n\u003ctd\u003e5 Filters: Luminance, Red, Green, Blue, H-Alpha\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-Alpha Bandwidth\u003c\/td\u003e\n\u003ctd\u003e7nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-Alpha Center Wavelength\u003c\/td\u003e\n\u003ctd\u003e656.3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLight Pollution Rejection\u003c\/td\u003e\n\u003ctd\u003eBlocks 589nm Sodium Line\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, 36mm Unmounted\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\"\u003eLuminance (L) 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\"\u003eRed (R) 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\"\u003eGreen (G) 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\"\u003eBlue (B) 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\"\u003eH-Alpha (Ha) 7nm Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eProtective Case\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":52941929513245,"sku":"OPT-LRGBH-1.25","price":517.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":52941929546013,"sku":"OPT-LRGBH-2","price":797.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":52941929578781,"sku":"OPT-LRGBH-RD36","price":615.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-HaLRGB-Filter-Kit.webp?v=1789606275"},{"product_id":"optolong-h-alpha-7nm-sii-6-5nm-oiii-6-5nm-filter-set-3-pcs","title":"Optolong Ha 7nm, OIII 6.5nm \u0026 SII 6.5nm Filter Set","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e\n\u003cstrong\u003eH-alpha Filter:\u003c\/strong\u003e 7nm Bandpass centered at 656nm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOxygen-III Filter:\u003c\/strong\u003e 6.5nm Bandpass centered at 500nm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSulphur-II Filter:\u003c\/strong\u003e 6.5nm Bandpass\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHubble Palette Ready:\u003c\/strong\u003e Complete SHO set for tri-band narrowband imaging\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFormat Options:\u003c\/strong\u003e Available in 1.25\" Mounted, 2\" Mounted, or 36mm Unmounted versions\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong Ha 7nm, OIII 6.5nm \u0026amp; SII 6.5nm Filter Set\u003c\/h2\u003e\n\u003cp\u003eThe Optolong Ha 7nm, OIII 6.5nm \u0026amp; SII 6.5nm Filter Set provides the three essential filters for creating high-contrast Hubble Palette images from light-polluted skies. This trio isolates the key emission lines from nebulae—Hydrogen-alpha at 656nm, Oxygen-III at 500nm, and Sulphur-II—with tight 7nm and 6.5nm bandpasses that reject unwanted skyglow and artificial light sources.\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 Hubble Palette: 6.5nm\/7nm Tri-Band Narrowband Imaging\u003c\/h3\u003e\n\u003cp\u003eThis filter set is engineered specifically for SHO imaging, where data from the Sulphur-II, Hydrogen-alpha, and Oxygen-III filters are mapped to the red, green, and blue channels of a final image. This technique, made famous by the Hubble Space Telescope, reveals incredible structural detail and color separation in emission nebulae like the Rosette Nebula (Caldwell 49) that are impossible to capture in broadband.\u003c\/p\u003e\n\u003cp\u003eDesigned for use with monochrome astronomy cameras or modified DSLRs, each filter isolates a specific emission line, allowing you to capture deep, high-contrast data one channel at a time, even under a bright moon or from a city 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\u003ePrecision Bandpasses: 7nm Ha, 6.5nm OIII, and 6.5nm SII\u003c\/h3\u003e\n\u003cp\u003eThe effectiveness of a narrowband filter is defined by its bandpass—the narrower, the better the contrast. The 7nm Ha filter captures the dominant 656nm wavelength present in nearly all emission nebulae. The even tighter 6.5nm bandpasses on the OIII and SII filters aggressively reject light pollution and background star signal, making faint nebular structures stand out dramatically.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eH-Alpha (7nm):\u003c\/strong\u003e Reveals the foundational hydrogen structure of nebulae with maximum signal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOIII (6.5nm):\u003c\/strong\u003e Isolates the 500nm blue-green light characteristic of planetary nebulae and supernova remnants, providing crucial detail and color contrast.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSII (6.5nm):\u003c\/strong\u003e Captures the deep red light from ionized sulfur, often tracing shock fronts and dense regions that differ from the Ha 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\u003eAdvanced Coatings for 1.25\", 2\", and 36mm Formats\u003c\/h3\u003e\n\u003cp\u003eOptolong utilizes an advanced ion-assisted deposition coating process across all filter sizes, ensuring durability and scratch resistance. This technology also provides a stable central wavelength (CWL) that does not drift with temperature changes during an imaging session, preventing signal loss.\u003c\/p\u003e\n\u003cp\u003eThis meticulous manufacturing process results in excellent transmission at the target wavelengths and high optical density outside the passband. The coatings are engineered to significantly reduce halos around bright stars, a common issue in narrowband imaging, particularly noticeable in the improved OIII filter performance.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOptolong 6.5nm\/7nm SHO Set vs. Wider Narrowband Filters\u003c\/h3\u003e\n\u003cp\u003eWhile wider filters, such as 12nm variants, can be a more forgiving starting point, the Optolong 6.5nm\/7nm set offers a significant step up in imaging capability. The primary advantage of the tighter bandpass is superior contrast and the ability to resolve finer nebular details.\u003c\/p\u003e\n\u003cp\u003eThe trade-off is that these filters require longer individual sub-exposure times to gather the same amount of signal as a wider filter. However, because they reject so much more background noise, the final integrated image achieves a much higher signal-to-noise ratio, producing cleaner, sharper, and more detailed results from any location.\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 \"Hubble Palette\" and why do I need this Optolong SHO filter set for it?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \"Hubble Palette\" is an imaging technique where narrowband data is mapped to RGB channels to create false-color images with dramatic detail and contrast. This \u003cstrong\u003eOptolong SHO set\u003c\/strong\u003e provides the three required filters: Sulphur-II (mapped to Red), Hydrogen-alpha (Green), and Oxygen-III (Blue), allowing you to produce these iconic images.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong Ha 7nm, OIII 6.5nm \u0026amp; SII 6.5nm filters with my color camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile technically possible, it is highly inefficient. These filters are designed for \u003cstrong\u003emonochrome cameras\u003c\/strong\u003e. A color camera's Bayer matrix blocks roughly 2\/3 of the incoming light for any given filter, requiring much longer exposures and producing lower-quality results. For color cameras, a multi-bandpass filter (like the L-eNhance or L-eXtreme) is a better choice.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Optolong 6.5nm OIII filter perform on the Orion Nebula (M42) from my city backyard?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003eOptolong 6.5nm OIII filter\u003c\/strong\u003e will excel on the Orion Nebula (M42) from a light-polluted location. Its tight 6.5nm bandpass will darken the sky background significantly, dramatically increasing the contrast of the delicate, wispy structures in the nebula's core and outer regions, which are rich in Oxygen-III emissions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat's the main benefit of using the Optolong 7nm Ha filter on the Rosette Nebula (Caldwell 49) with my monochrome camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary benefit is immense contrast. The Rosette Nebula (Caldwell 49) is a massive cloud of hydrogen. The \u003cstrong\u003eOptolong 7nm Ha filter\u003c\/strong\u003e isolates its dominant 656nm emission line, rejecting moonlight, skyglow, and broadband light from stars. This allows your monochrome camera to record deep, detailed structural information of the nebula itself, separate from the background.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is the Ha filter in this Optolong set 7nm while the OIII and SII are 6.5nm?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eHydrogen-alpha is typically the strongest signal in most emission nebulae. The slightly wider \u003cstrong\u003e7nm bandpass\u003c\/strong\u003e for the Ha filter ensures maximum signal capture for this critical channel. The OIII and SII signals are often weaker, so the tighter \u003cstrong\u003e6.5nm bandpass\u003c\/strong\u003e is used to maximize contrast by more aggressively rejecting background light pollution and skyglow, improving the signal-to-noise ratio for these fainter details.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo these Optolong narrowband filters require longer exposure times than LRGB filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, significantly longer. LRGB filters have very wide bandpasses to capture as much light as possible. The \u003cstrong\u003eOptolong narrowband filters\u003c\/strong\u003e in this set have extremely narrow 6.5nm and 7nm bandpasses. While this is key to their high-contrast performance, it means individual sub-exposures must be much longer (typically 3-10 minutes or more) to achieve a strong signal.\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, OIII, SII\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-Alpha Bandpass\u003c\/td\u003e\n\u003ctd\u003e7nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-Alpha Central Wavelength\u003c\/td\u003e\n\u003ctd\u003e656nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOIII Bandpass\u003c\/td\u003e\n\u003ctd\u003e6.5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOIII Central Wavelength\u003c\/td\u003e\n\u003ctd\u003e500nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSII Bandpass\u003c\/td\u003e\n\u003ctd\u003e6.5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, 36mm Round Unmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating Technology\u003c\/td\u003e\n\u003ctd\u003eIon-assisted deposition\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\"\u003eH-Alpha 7nm Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eOIII 6.5nm 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\"\u003eSII 6.5nm 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\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":52941930594589,"sku":"OPT-SHO-1.25","price":651.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":52941930627357,"sku":"OPT-SHO-2","price":937.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":52941930660125,"sku":"OPT-SHO-RD36","price":769.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-improved-NB-filters-SHO6-5nm-narrowband-filter-Kit-1_30b6be85-daea-48f5-b858-b12bd65e15c7.jpg?v=1789592457"},{"product_id":"optolong-l-pro-uhc-clip-filter-kit","title":"Optolong L-Pro + UHC Clip Filter Kit","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eTwo Optolong Clip-in Light Pollution Filters in One Kit\u003c\/li\u003e\n\u003cli\u003eL-Pro: Multi-Bandpass Suppression Across 380-750nm\u003c\/li\u003e\n\u003cli\u003eUHC: \u0026gt;99% Blocking of Mercury and Sodium Vapor Light (OD3)\u003c\/li\u003e\n\u003cli\u003eNatural Color on Galaxies, High Contrast on Emission Nebulae\u003c\/li\u003e\n\u003cli\u003eFits Inside the Camera Body, Works With Any Lens\u003c\/li\u003e\n\u003cli\u003eCanon EOS APS-C, Canon EOS Full Frame and Nikon Full Frame Versions\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOptolong L-Pro + UHC Clip Filter Kit\u003c\/h2\u003e\n\u003cp\u003eThe Optolong L-Pro + UHC Clip Filter Kit pairs Optolong's two broadband light pollution filters in clip-in format for your DSLR. The L-Pro is the multi-bandpass filter for natural color across a 380-750nm spectrum; the UHC is the narrower, higher-contrast filter that blocks more than 99% of mercury and sodium vapor light. Both clip inside the camera body, so either one works with any lens you mount, and you choose the filter for the target and the sky rather than compromising on one.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eL-Pro: Multi-Bandpass Suppression for Natural-Color Imaging\u003c\/h3\u003e\n\u003cp\u003eThe L-Pro selectively rejects the dominant emission lines of mercury vapor, high-pressure sodium and low-pressure sodium streetlights, plus the natural skyglow from neutral oxygen in the atmosphere, across its 380-750nm operating range. Its balanced, multi-bandpass design keeps the natural colors of broadband targets such as galaxies, reflection nebulae and globular clusters, so images need far less color correction. It still passes the key nebula lines, including H-Alpha, OIII, SII and H-Beta, and it blocks infrared on its own.\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: Ultra High Contrast for Emission Nebulae Under City Skies\u003c\/h3\u003e\n\u003cp\u003eThe UHC takes the more aggressive approach. At an optical density of OD3 it blocks more than 99% of light from mercury vapor and sodium vapor lamps, while transmitting the emission lines of nebulae at OIII (496nm, 500nm), H-Beta (486nm) and H-Alpha (656nm). Its narrower passband gives higher contrast than a CLS filter, which makes it the better choice where light pollution is severe. Its substantial red passband captures H-Alpha well on unmodified DSLRs, for targets like the Orion Nebula (M42).\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\u003eChoosing Between the L-Pro and the UHC on a Given Night\u003c\/h3\u003e\n\u003cp\u003eThe two filters cover different targets, which is why they are worth having together:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eUse the L-Pro\u003c\/strong\u003e for galaxies, reflection nebulae, star clusters and Milky Way landscapes, or whenever natural star color matters. It is the more versatile filter from suburban skies.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUse the UHC\u003c\/strong\u003e for emission nebulae from heavily light-polluted urban skies, where maximum contrast is the goal. It dims broadband targets such as galaxies, so switch back to the L-Pro for those.\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\u003eClip-in Format: Filtration Inside the Camera, Any Lens in Front\u003c\/h3\u003e\n\u003cp\u003eEach clip filter sits inside the camera body, so the light pollution filter works with whatever lens or telescope adapter you attach. The kit comes in three versions, each fitting one camera family:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCanon EOS APS-C:\u003c\/strong\u003e including the EOS 7D, 10D, 20D, 30D, 40D, 50D, 60D\/60Da, 70D, 550D, 600D, 650D, 700D, 1100D and 1200D.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCanon EOS Full Frame:\u003c\/strong\u003e Canon EOS full-frame DSLR bodies.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNikon Full Frame:\u003c\/strong\u003e D600, D610, D700, D750, D800, D800E, D810, D810A and Df.\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\u003eOptical Quality and Durable Coatings\u003c\/h3\u003e\n\u003cp\u003eBoth filters are polished to a 60\/40 surface quality per MIL-O-13830, and the UHC to a transmitted wavefront of ¼ λ with 30s parallelism, so neither softens your images. Ion-assisted deposition coatings resist scratching and keep the central wavelength stable as the temperature changes through the night. Light pollution filters increase the contrast between the target and the sky; they do not make the object itself brighter.\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 difference between the L-Pro and the UHC in this kit?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003eL-Pro\u003c\/strong\u003e is a multi-bandpass filter that blocks the main streetlight wavelengths while preserving natural color, which suits galaxies, reflection nebulae and star clusters. The \u003cstrong\u003eUHC\u003c\/strong\u003e has a narrower passband and blocks more than 99% of mercury and sodium vapor light, giving higher contrast on emission nebulae from heavily light-polluted skies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhich version of the Optolong clip filter kit fits my camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eChoose the version for your camera family: \u003cstrong\u003eCanon EOS APS-C\u003c\/strong\u003e (for example the EOS 7D, 60D\/60Da, 70D, 600D, 700D), \u003cstrong\u003eCanon EOS Full Frame\u003c\/strong\u003e, or \u003cstrong\u003eNikon Full Frame\u003c\/strong\u003e (D600, D610, D700, D750, D800, D800E, D810, D810A, Df). Both filters in a kit are the same clip format.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use these clip filters with an unmodified DSLR?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The UHC is suited to color cameras and \u003cstrong\u003eunmodified DSLRs\u003c\/strong\u003e, and its substantial red passband captures H-Alpha well. The L-Pro works for both visual observation and astrophotography and preserves natural color with any color camera.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhich filter should I use to photograph the Andromeda Galaxy (M31) from the suburbs?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eUse the \u003cstrong\u003eL-Pro\u003c\/strong\u003e. It darkens the suburban sky while preserving the galaxy's natural colors. The UHC blocks much of the broadband light a galaxy emits, so it would dim M31 rather than improve it.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhich filter should I use for the Orion Nebula (M42) from a city?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eUse the \u003cstrong\u003eUHC\u003c\/strong\u003e. It blocks the city skyglow while passing the nebula's H-Alpha, H-Beta and OIII light, bringing out faint outer structure. The L-Pro also works on M42 and keeps more natural star colors in the surrounding field, with less contrast from severely light-polluted skies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use these filters to look at the Sun?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eNo. Never use these filters for solar observation.\u003c\/strong\u003e They are not designed for the Sun and do not block its intense radiation. Looking at the Sun through them will cause permanent blindness.\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\u003eKit Contents\u003c\/td\u003e\n\u003ctd\u003eOptolong L-Pro clip filter, Optolong UHC clip filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eL-Pro Spectrum\u003c\/td\u003e\n\u003ctd\u003e380-750nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eL-Pro Filter Type\u003c\/td\u003e\n\u003ctd\u003eMulti-bandpass light pollution filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eUHC Blocking Range\u003c\/td\u003e\n\u003ctd\u003e300-700nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eUHC Blocking Depth\u003c\/td\u003e\n\u003ctd\u003eOD3, light pollution line blocking \u0026gt;99%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eUHC Transmitted Wavefront RMS\u003c\/td\u003e\n\u003ctd\u003e¼ λ\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eUHC Parallelism\u003c\/td\u003e\n\u003ctd\u003e30s\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40 (MIL-O-13830)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating Technology\u003c\/td\u003e\n\u003ctd\u003eIon-assisted deposition multi-layer coatings\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Versions\u003c\/td\u003e\n\u003ctd\u003eClip for Canon EOS APS-C, Clip for Canon EOS Full Frame, Clip for Nikon Full Frame\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eOptolong L-Pro Clip Filter (in selected version)\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\"\u003eOptolong UHC Clip Filter (in selected version)\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"Clip for Canon EOS APS-C","offer_id":52941931872541,"sku":"OPT-LPRO-UHC-EOS-APSC","price":419.0,"currency_code":"CAD","in_stock":true},{"title":"Clip for Canon EOS Full Frame","offer_id":52941931905309,"sku":"OPT-LPRO-UHC-EOS-FF","price":419.0,"currency_code":"CAD","in_stock":true},{"title":"Clip for Nikon Full Frame","offer_id":52941931938077,"sku":"OPT-LPRO-UHC-NIKON-FF","price":419.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-UHC-L-Pro-Kit.webp?v=1789606223"}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/collections\/Optolong-Logo.jpg?v=1683750805","url":"https:\/\/davidastro.com\/collections\/optolong.oembed?page=2","provider":"David Astro","version":"1.0","type":"link"}