{"product_id":"antlia-3nm-narrowband-h-beta-pro-filter","title":"Antlia 3nm Narrowband H-Beta Pro Filter - 2\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eIsolates the H-Beta emission line at 486.1nm\u003c\/li\u003e\n\u003cli\u003e3nm bandpass (FWHM) to enhance contrast of emission targets\u003c\/li\u003e\n\u003cli\u003e88% peak transmission\u003c\/li\u003e\n\u003cli\u003eGreater than OD5 blocking across 300-1100nm\u003c\/li\u003e\n\u003cli\u003eUsable down to f\/3 with minimal loss of signal\u003c\/li\u003e\n\u003cli\u003e2\" mounted, male M48x0.75 thread\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\u003eAntlia 3nm Narrowband H-Beta Pro Filter - 2\"\u003c\/h2\u003e\n\u003cp\u003eThe Antlia 3nm Narrowband H-Beta Pro filter isolates the hydrogen-beta emission line at a central wavelength of 486.1nm with an extremely tight 3nm bandpass. This narrow window achieves a peak transmission of 88% while delivering greater than OD5 out-of-band blocking across the 300-1100nm range. It is built on a single, non-glued 2mm optical substrate with a transmitted wavefront of Lambda\/4 or better, and all Antlia narrowband Pro filters can be used down to f\/3 with minimal loss of signal.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e3nm Bandpass at 486.1nm\u003c\/h3\u003e\n\u003cp\u003eThe 3nm band is centred on the 486.1nm H-Beta line. As the bandwidth narrows, these filters enhance the contrast of emission targets by reducing unwanted background signal. Peak transmission is 88%.\u003c\/p\u003e\n\u003cp\u003eThe filter is only effective for deep-sky objects that contain H-Beta emission, and its targets are H-Beta emission nebulae; the California Nebula (NGC 1499) is a classic one. It can be used in light-polluted areas and at dark sites and extends imaging time when the moon is up.\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;OD5 Blocking: Signal Purity from 300nm to 1100nm\u003c\/h3\u003e\n\u003cp\u003eOut-of-band blocking is rated greater than OD5 (0.001%) from 300nm to 1100nm. This ensures an excellent signal-to-noise ratio (SNR) and effective cutoff rates that minimize interference from other wavelengths.\u003c\/p\u003e\n\u003cp\u003eAntlia adds that its optical reliability reduces post-processing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eLambda\/4 Optics on a Single Substrate\u003c\/h3\u003e\n\u003cp\u003eThe filter is built on a single, non-glued substrate, which eliminates internal reflections. Its steep spectral profile minimizes halos around bright stars. This 2\" filter is mounted; unmounted Antlia filters have blackened edges.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTransmitted Wavefront:\u003c\/strong\u003e Lambda\/4 or better.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eParallelism:\u003c\/strong\u003e Less than 30 arcseconds.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSurface Quality:\u003c\/strong\u003e 60\/40 scratch\/dig per MIL-O-13830.\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\u003eEngineered for Fast Optics: Usable Down to f\/3\u003c\/h3\u003e\n\u003cp\u003eIn fast telescopes the steeper light cone shifts a \u003ca href=\"\/en-us\/collections\/narrowband-filters\"\u003enarrowband filter\u003c\/a\u003e's central wavelength toward shorter wavelengths (blue shift).\u003c\/p\u003e\n\u003cp\u003eAll Antlia narrowband Pro filters can be used down to f\/3 with minimal loss of signal.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe Antlia 3nm Pro Series: Building a Full Narrowband Set\u003c\/h3\u003e\n\u003cp\u003eAntlia's 3nm Pro series covers H-alpha, SII, OIII and H-Beta, and these four narrow channels give a greater range of combinations in post-production.\u003c\/p\u003e\n\u003cp\u003eA 3nm band passes less moonlight and skyglow around the line than a 7nm band, so the background is darker.\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 Antlia 3nm H-Beta Pro perform on the California Nebula (NGC 1499) with an f\/4 scope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe California Nebula is an H-Beta emission nebula, the kind of target this filter is made for. f\/4 is slower than the f\/3 limit given for the narrowband Pro filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Antlia 3nm H-Beta Pro filter to image from my light-polluted backyard?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. It can be used in light-polluted areas. The 3nm band and \u0026gt;OD5 blocking let only light close to the 486.1nm line through.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy would I choose the Antlia 3nm H-Beta Pro instead of a more common H-alpha filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eH-alpha is the stronger hydrogen line in most emission nebulae. H-Beta adds a fourth channel; the four 3nm Pro channels give a greater range of combinations in post-production.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does the \u0026gt;OD5 blocking on the Antlia 3nm H-Beta Pro filter mean for my images?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eOD5 blocking\u003c\/strong\u003e means that light outside the filter's 3nm bandpass is attenuated to 0.001% of its original intensity. It is rated from 300nm to 1100nm and ensures an excellent signal-to-noise ratio.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Antlia 3nm H-Beta Pro filter safe for solar viewing or visual use?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eNo.\u003c\/strong\u003e Do not look at the Sun with this filter. Solar imaging and night visual observation are both listed as not recommended.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the benefit of the single-substrate design in the Antlia 3nm H-Beta Pro?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe single, non-glued substrate eliminates internal reflections.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Antlia 3nm H-Beta Pro filter cause halos around bright stars?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe sharp cutoff of the 3nm Pro filters is engineered to reduce halos around bright stars, and the steep spectral profile minimizes them. Very bright stars can still show some halo.\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\u003eH-Beta Narrowband (3nm Pro series)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCentral Wavelength (CWL)\u003c\/td\u003e\n\u003ctd\u003e486.1nm\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\u003ePeak Transmission\u003c\/td\u003e\n\u003ctd\u003e88%\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\u003eBlocking Depth\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;OD5 (0.001%)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRecommended F-Ratio\u003c\/td\u003e\n\u003ctd\u003eUsable down to f\/3 with minimal loss of signal\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Size\u003c\/td\u003e\n\u003ctd\u003e2\" Mounted (M48x0.75 Threads)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thickness\u003c\/td\u003e\n\u003ctd\u003e2mm +\/-0.05mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eOptical, single \/ non-glued\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40 (per MIL-O-13830)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmitted Wavefront\u003c\/td\u003e\n\u003ctd\u003eLambda\/4 or better\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e\u0026lt; 30 arcseconds\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eUsage Warning\u003c\/td\u003e\n\u003ctd\u003eNot recommended for solar imaging or night visual observation. Do not look at the Sun with this filter directly.\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\"\u003eAntlia 3nm H-Beta Pro filter, 2\" mounted\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\nAntlia 3-year warranty against delamination.\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Antlia","offers":[{"title":"2\" Mounted","offer_id":51932624322845,"sku":"ANT-HB-3NM-2","price":395.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/antlia-src-o4IypmAQwyQ84yQ8_2328020a-7b3a-4ad6-b185-89aa4a50f124.jpg?v=1792549993","url":"https:\/\/davidastro.com\/en-us\/products\/antlia-3nm-narrowband-h-beta-pro-filter","provider":"David Astro","version":"1.0","type":"link"}