{"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","url":"https:\/\/davidastro.com\/fr\/products\/optolong-night-sky-h-alpha-filter-ir-pass-630nm","provider":"David Astro","version":"1.0","type":"link"}