{"product_id":"antlia-7nm-narrowband-h-alpha-prime-filter","title":"Antlia 7nm Narrowband H-alpha Prime Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e7nm Full Width at Half Maximum (FWHM) Bandpass\u003c\/li\u003e\n\u003cli\u003eCentered on the 656.3nm Hydrogen-alpha Emission Line\u003c\/li\u003e\n\u003cli\u003ePasses NII Emission Lines at 654.8nm and 658.3nm\u003c\/li\u003e\n\u003cli\u003eGreater than 90% Peak Transmission\u003c\/li\u003e\n\u003cli\u003eOD4 Blocking (\u0026gt;99.99%) of Out-of-Band Wavelengths from 300-1000nm\u003c\/li\u003e\n\u003cli\u003eLambda\/4 or Better Transmitted Wavefront\u003c\/li\u003e\n\u003cli\u003eUsable with Systems as Fast as f\/2 with Minimal Loss of Signal\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\u003eAntlia 7nm Narrowband H-alpha Prime Filter\u003c\/h2\u003e\n\u003cp\u003eThe Antlia 7nm Narrowband H-alpha Prime Filter isolates the critical 656.3nm wavelength with a 7nm FWHM bandpass, achieving over 90% peak transmission for maximum signal. By also passing the adjacent NII emission lines at 654.8nm and 658.3nm, this filter is effective for deep-sky objects that contain H-alpha and NII emissions. Its OD4 blocking across the 300-1000nm spectrum delivers an excellent signal-to-noise ratio, and it can be used with nearly all systems as fast as f\/2 with minimal loss in emission 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\u003e7nm FWHM: Capturing H-alpha and NII at \u0026gt;90% Transmission\u003c\/h3\u003e\n\u003cp\u003eThe 7nm bandpass strikes a critical balance between contrast and signal strength. Antlia says the 7nm Prime filters deliver superior SNR and better contrast, and the bandpass is wide enough to pass not only the primary H-alpha line at 656.3nm but also the nearby Nitrogen-II (NII) lines at 654.8nm and 658.3nm. With peak transmission above 90%, it suits the targets Antlia names: H-alpha and NII emission nebulae, planetary nebulae, Wolf-Rayet nebulae such as the Crescent Nebula (NGC 6888), 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\u003eOD4 Blocking and Lambda\/4 Optics for High-Contrast Results\u003c\/h3\u003e\n\u003cp\u003eSignal purity is defined by what a filter rejects. The H-alpha Prime filter provides OD4 blocking from 300nm to 1000nm, blocking more than 99.99% of out-of-band light, which Antlia says delivers an excellent SNR and minimizes interference from other wavelengths. The filter is built on a single, non-glued optical substrate with a Lambda\/4 or better transmitted wavefront and parallelism under 30 arcseconds, and its steep spectral profile minimizes halos around bright stars.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eEngineered for Modern Systems Down to f\/2\u003c\/h3\u003e\n\u003cp\u003eFast optical systems present a challenge for narrowband filters due to the steep light cone, which can cause band-shifting and signal loss. Antlia states that, with their wider FWHM, 7nm Prime filters can be used with nearly all systems as fast as f\/2 with minimal loss in emission 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\u003eAntlia 7nm Prime vs. 3nm Pro: Choosing the Right Bandpass\u003c\/h3\u003e\n\u003cp\u003eThe choice between a 7nm and a 3nm filter depends on your equipment and sky conditions. The 7nm Prime suits very fast optical systems, down to f\/2, and imagers who want to capture both H-alpha and NII data simultaneously.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eChoose the 7nm Prime for:\u003c\/strong\u003e Faster signal acquisition, use with systems as fast as f\/2, and capturing combined H-alpha and NII detail.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConsider a 3nm Pro for:\u003c\/strong\u003e Maximizing contrast in light-polluted areas or extending imaging time when the moon is up. Antlia rates the 3nm Pro series as usable down to f\/3.\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 Antlia 7nm H-alpha Prime filter perform on an f\/2 system?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAntlia states that, with their wider FWHM, 7nm Prime filters can be used with nearly all systems as fast as f\/2 with minimal loss in emission signal.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Antlia 7nm H-alpha Prime suitable for the Eagle Nebula (M16)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The 7nm FWHM is wide enough to transmit the H-alpha line at 656.3nm as well as the important NII emission lines at 654.8nm and 658.3nm. The Eagle Nebula is an H-alpha emission nebula, one of the target types Antlia lists for this filter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is it important that the Antlia 7nm H-alpha Prime filter also passes NII emission lines?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAntlia lists H-alpha and NII emission nebulae, planetary nebulae, Wolf-Rayet nebulae and supernova remnants as targets. The \u003cstrong\u003eAntlia 7nm H-alpha Prime\u003c\/strong\u003e FWHM is wide enough to pass both the H-alpha line and the NII lines at 654.8nm and 658.3nm, so it records the combined signal from these objects.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhen should I choose the Antlia 7nm Prime over a 3nm filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eChoose the \u003cstrong\u003eAntlia 7nm Prime\u003c\/strong\u003e filter if you are using a very fast optical system (Antlia rates it for systems as fast as f\/2) or want to gather signal more quickly. A 3nm filter offers higher contrast from its narrower bandpass, at the cost of longer exposures; Antlia rates its 3nm Pro series as usable down to f\/3.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Antlia 7nm H-alpha Prime filter for visual observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo. Antlia lists night visual observation as not recommended for this filter. It is designed for astrophotography of deep-sky objects that contain H-alpha and NII emissions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Antlia 7nm H-alpha Prime filter minimize halos around bright stars?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAntlia attributes this to three points on the \u003cstrong\u003eAntlia 7nm H-alpha Prime\u003c\/strong\u003e: a steep spectral profile that minimizes halos around bright stars, a \u003cstrong\u003esingle, non-glued substrate\u003c\/strong\u003e to eliminate internal reflections, and \u003cstrong\u003eedge blackening\u003c\/strong\u003e of unmounted filters to eliminate internal reflections from stray light.\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-alpha narrowband (7nm Prime series)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCentral Wavelength (CWL)\u003c\/td\u003e\n\u003ctd\u003e656.3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandpass (FWHM)\u003c\/td\u003e\n\u003ctd\u003e7nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePeak Transmission\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAdditional Lines Passed\u003c\/td\u003e\n\u003ctd\u003eNII at 654.8nm and 658.3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;OD4 (0.01%) @ 300-1000nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRecommended F-Ratio\u003c\/td\u003e\n\u003ctd\u003eUsable with systems as fast as f\/2 with minimal loss of signal\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\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eOptical, single \/ non-glued substrate\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40 (scratch\/dig) per MIL-O-13830\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thickness\u003c\/td\u003e\n\u003ctd\u003e2mm +\/-0.05mm (36mm unmounted)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEdge Treatment\u003c\/td\u003e\n\u003ctd\u003eUnmounted filters are edge blackened\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e36mm Round Unmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNot Recommended For\u003c\/td\u003e\n\u003ctd\u003eSolar imaging, night visual observation\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWarranty\u003c\/td\u003e\n\u003ctd\u003e3-years against delamination\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003cp\u003eThis product is covered by the Antlia 3-Year Warranty against delamination.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Antlia","offers":[{"title":"36mm Round Unmounted","offer_id":51932624584989,"sku":"ANT-HA-7NM-RD36","price":158.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/antlia-src-ooN2nuAcwoAY4oAY_3b161601-b314-4f0f-97ef-3beb6cc35c39.jpg?v=1792549993","url":"https:\/\/davidastro.com\/fr-int\/products\/antlia-7nm-narrowband-h-alpha-prime-filter","provider":"David Astro","version":"1.0","type":"link"}