{"product_id":"baader-planetarium-h-alpha-bandpass-filter-20nm","title":"Baader Planetarium H-alpha Bandpass Filter (20nm)","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eH-alpha Bandpass Filter in 1.25\" \u0026amp; 2\" Sizes\u003c\/li\u003e\n\u003cli\u003e20nm FWHM Bandwidth\u003c\/li\u003e\n\u003cli\u003e656.3nm Center Wavelength\u003c\/li\u003e\n\u003cli\u003eOptimized for Color CMOS\/CCD Cameras\u003c\/li\u003e\n\u003cli\u003eHigh-Contrast for Visual and Photographic Use\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section-center\"\u003e\n      \u003ch2\u003eBaader H-alpha Bandpass Filter (20nm)\u003c\/h2\u003e\n      \u003cp\u003eThe Baader H-alpha Bandpass filter, available in 1.25\" and 2\" sizes, isolates the critical 656.3nm wavelength of ionized hydrogen with a 20nm FWHM, dramatically increasing the contrast of emission nebulae. This filter is engineered for both visual deep-sky observing and as a powerful enhancement for color CMOS and CCD cameras, allowing you to cut through light pollution and capture detailed H-II regions from any location.\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 20nm Bandpass for High-Contrast Deep-Sky Views\u003c\/h3\u003e\n      \u003cp\u003eBy selectively passing a 20nm window of light centered on the 656.3nm H-alpha line, this filter renders the sky background profoundly dark. This isolates the faint, glowing structures of emission nebulae like the North America Nebula (NGC 7000), making them stand out against a black field of view. The 20nm bandwidth is a carefully chosen compromise, offering a significant contrast boost while remaining bright enough for effective visual use in a variety of telescopes.\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\u003eOptimized for Color CMOS and CCD Imaging at 656.3nm\u003c\/h3\u003e\n      \u003cp\u003eFor imagers using one-shot color cameras, this filter acts as a supercharged red filter. It replaces the standard red channel in an RGB sequence, dedicating all your signal collection at that wavelength to the most important structures in emission nebulae. This technique allows you to produce high-contrast, detailed images of H-II regions without investing in a full monochrome camera and narrowband filter 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\u003eVisual Enhancement for All Telescope f-ratios\u003c\/h3\u003e\n      \u003cp\u003eUnlike extremely narrow imaging filters that can be too dim for the human eye, the 20nm bandpass provides a tangible boost in nebular visibility without an excessive loss of light. This filter is designed to work effectively across all telescope f-ratios, making it a versatile tool for any observer looking to punch through local light pollution and reveal the hidden structure in faint deep-sky objects.\u003c\/p\u003e\n      \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eImportant Safety Warning:\u003c\/strong\u003e This filter is designed for nighttime deep-sky observing only. It is \u003cstrong\u003eNOT\u003c\/strong\u003e a solar filter and must never be used for direct viewing of the sun. Permanent eye damage will result.\u003c\/li\u003e\n      \u003c\/ul\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the Baader 20nm H-alpha filter primarily used for?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThis filter is designed to dramatically increase the contrast of \u003cstrong\u003eemission nebulae\u003c\/strong\u003e (H-II regions) for both visual observing and astrophotography. It isolates the 656.3nm H-alpha wavelength, making objects like the North America Nebula (NGC 7000) or the Orion Nebula (M42) stand out, especially from light-polluted areas.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhy choose a 20nm bandpass for the Baader H-alpha filter instead of a narrower one like 7nm?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eA 20nm bandpass offers a crucial balance. It's narrow enough to provide a major contrast enhancement by blocking light pollution, but wide enough to remain bright for \u003cstrong\u003evisual observing\u003c\/strong\u003e. Narrower filters (like 7nm or 3nm) are excellent for imaging but are often too dim for the human eye to see through, especially with smaller telescopes.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Baader 20nm H-alpha filter improve my images of the North America Nebula (NGC 7000) with a color camera?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eWhen used with a color CMOS or CCD camera, this filter acts as an enhanced red filter. It isolates the rich H-alpha signal from the nebula while rejecting skyglow, moonlight, and other sources of light pollution. This results in a much stronger, more detailed signal from the nebula's structure, allowing you to capture impressive images even from a suburban backyard.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Baader 20nm H-alpha filter with my f\/5 Newtonian for visual observing?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, absolutely. The filter is designed to perform well across all f-ratios, including faster systems like an f\/5 Newtonian. The 20nm bandwidth ensures the view remains bright enough to be effective, providing a significant contrast boost on emission nebulae without dimming the image excessively.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Baader 20nm H-alpha filter safe for viewing the sun?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003e\u003cstrong\u003eNO. This is not a solar filter.\u003c\/strong\u003e You must never use this filter for any type of solar observation. Viewing the sun through this filter without a proper, full-aperture solar filter will cause immediate and permanent eye damage.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhich size of the Baader 20nm H-alpha filter fits my filter wheel and eyepieces?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eChoose the size that matches your accessories. The \u003cstrong\u003e1.25\" version\u003c\/strong\u003e is housed in a standard 1.25\" cell with standard filter threads and threads directly into the barrel of any 1.25\" eyepiece or into a standard 1.25\" filter wheel. The \u003cstrong\u003e2\" version\u003c\/strong\u003e is the right choice if your eyepieces, diagonal or filter wheel use the 2\" format. Both sizes offer the same 20nm bandpass centered on 656.3nm.\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\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.01\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter shape\u003c\/td\u003e\n\u003ctd\u003eround\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSingle or Set?\u003c\/td\u003e\n\u003ctd\u003eSingle Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter mounted\u003c\/td\u003e\n\u003ctd\u003eMounted (LPFC 6mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Usage\u003c\/td\u003e\n\u003ctd\u003eCMOS, CCD, H-alpha, IR-Cut\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thickness (without cell)\u003c\/td\u003e\n\u003ctd\u003e2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003e1.25\" Round Mounted\u003c\/h3\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eH-alpha Bandpass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSize\u003c\/td\u003e\n\u003ctd\u003e1.25\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandwidth (FWHM)\u003c\/td\u003e\n\u003ctd\u003e20 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCenter Wavelength (CWL)\u003c\/td\u003e\n\u003ctd\u003e656.3 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Application\u003c\/td\u003e\n\u003ctd\u003eVisual \u0026amp; Photographic Deep-Sky\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSolar Safe\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003edielectrically coated, planeoptically polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003e2\" Round Mounted\u003c\/h3\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eBandpass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWavelength\u003c\/td\u003e\n\u003ctd\u003eH-alpha\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCenter Wavelength (CWL)\u003c\/td\u003e\n\u003ctd\u003e656.3 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandpass (FWHM)\u003c\/td\u003e\n\u003ctd\u003e20 nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Size\u003c\/td\u003e\n\u003ctd\u003e2\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Use\u003c\/td\u003e\n\u003ctd\u003eDeep-Sky Visual \u0026amp; Photography\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSolar Safe\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003eReflex-Blocker™ hard coated, dielectrically coated, planeoptically polished\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cul class=\"DAV-grid\"\u003e\n  \u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/baader-planetarium-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eBaader Planetarium Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"1.25\" Round Mounted","offer_id":52913208295709,"sku":"BAA-2961850","price":137.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Round Mounted","offer_id":52913208328477,"sku":"BAA-2961853","price":241.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/BaaderPlanetarium-H-alpha-1-Bandpass-filter-20nm-1_7ee6dc6e-e6aa-4171-b451-2d6ded4e57d9.jpg?v=1789088148","url":"https:\/\/davidastro.com\/products\/baader-planetarium-h-alpha-bandpass-filter-20nm","provider":"David Astro","version":"1.0","type":"link"}