{"product_id":"antlia-7nm-narrowband-oiii-prime-filter","title":"Antlia 7nm Narrowband OIII Prime Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eIsolates the 500.7nm OIII emission line\u003c\/li\u003e\n\u003cli\u003e7nm FWHM bandpass for high signal capture\u003c\/li\u003e\n\u003cli\u003eGreater than 90% peak transmission\u003c\/li\u003e\n\u003cli\u003eOD4 (0.01%) out-of-band blocking from 300-1000nm\u003c\/li\u003e\n\u003cli\u003eUsable with systems as fast as f\/2 with minimal loss of signal\u003c\/li\u003e\n\u003cli\u003e2mm thick single substrate with Lambda\/4 or better 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\u003eAntlia 7nm Narrowband OIII Prime Filter - 36mm Unmounted\u003c\/h2\u003e\n\u003cp\u003eThe Antlia 7nm Narrowband OIII Prime Filter isolates the critical 500.7nm oxygen-III emission line with a tight 7nm full width at half maximum (FWHM). With over 90% peak transmission, this 36mm unmounted filter is designed for OIII emission nebulae, planetary nebulae, Wolf-Rayet nebulae and supernova remnants, and can be used with nearly all systems as fast as f\/2 with minimal loss in emission signal. It achieves its high signal-to-noise ratio through greater than OD4 out-of-band blocking, suppressing unwanted light across the 300-1000nm spectrum by a factor of 10,000.\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 Bandpass with \u0026gt;90% Transmission at 500.7nm\u003c\/h3\u003e\n\u003cp\u003eThis filter's design centers on a 7nm bandpass, which provides an excellent balance between signal strength and contrast. By achieving over 90% transmission at the 500.7nm OIII wavelength, it gathers the maximum amount of photons from faint emission structures. The 7nm FWHM is wide enough to deliver bright, high-signal images with shorter exposure times compared to ultra-narrowband filters, while still offering significant rejection of 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\u003e\u0026gt;OD4 Blocking for High-Contrast Imaging\u003c\/h3\u003e\n\u003cp\u003eThe foundation of high-contrast narrowband imaging is the rejection of all unwanted light. The Antlia OIII Prime filter provides an optical density of greater than OD4, which corresponds to blocking 99.99% of light outside the 7nm passband. Antlia says this blocking from 300-1000nm delivers an excellent signal-to-noise ratio and minimizes interference from other wavelengths, for use in light-polluted areas and at 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\u003eEngineered for Optics as Fast as f\/2\u003c\/h3\u003e\n\u003cp\u003eA key challenge with narrowband filters is band-shifting in fast optical systems. 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\u003eLambda\/4 Single Substrate Construction\u003c\/h3\u003e\n\u003cp\u003ePhysical construction is critical to optical integrity. This filter is built from a single, non-glued substrate of optical glass, which Antlia uses to eliminate internal reflections. The filter is specified with a transmitted wavefront of Lambda\/4 or better and parallelism under 30 arcseconds, and its edges are blackened to eliminate internal reflections from stray light.\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: When to Choose a Wider Bandpass\u003c\/h3\u003e\n\u003cp\u003eAntlia produces both 7nm Prime and 3nm Pro series filters, each suited for different conditions. The choice depends on your sky quality and optical system.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eChoose the 7nm Prime (This Filter):\u003c\/strong\u003e Ideal for faster optical systems (f\/2 to f\/5), darker sky sites, or when you want to prioritize shorter exposure times. The wider bandpass is more forgiving of slight band-shifting and gathers more signal in a given time.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConsider a 3nm Pro Filter:\u003c\/strong\u003e Better suited for heavily light-polluted urban skies or when you want more contrast. The narrower bandpass rejects more background light but typically requires longer sub-exposures to achieve the same signal level. 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\"\u003eWhat is the main advantage of the Antlia 7nm OIII Prime filter's 7nm bandpass?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e7nm bandpass\u003c\/strong\u003e balances light-gathering power and contrast. It allows for shorter exposure times than ultra-narrow 3nm filters while its OD4 blocking still minimizes interference from other wavelengths, which suits OIII targets such as planetary nebulae like the Dumbbell Nebula (M27).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Antlia 7nm OIII Prime perform on the Veil Nebula (NGC 6960) with an f\/4 Newtonian?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Veil Nebula is a supernova remnant with strong OIII emission, a target type Antlia lists for this filter. Antlia rates the 7nm Prime filters for nearly all systems as fast as f\/2 with minimal loss in emission signal, so an f\/4 Newtonian is within that range. The \u003cstrong\u003eOD4 blocking\u003c\/strong\u003e minimizes interference from wavelengths outside the passband.\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 OIII Prime filter in an f\/2 imaging system?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. Antlia states that 7nm Prime filters are \u003cstrong\u003eusable with nearly all systems as fast as f\/2\u003c\/strong\u003e 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\"\u003eWhat does the Lambda\/4 transmitted wavefront specification mean for the Antlia 7nm OIII Prime?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eTransmitted wavefront describes how much a filter distorts the light passing through it. \u003cstrong\u003eLambda\/4 or better\u003c\/strong\u003e means the wavefront error added by the filter is a quarter of a wavelength or less, which keeps its effect on image sharpness small.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy shouldn't I use the Antlia 7nm OIII Prime filter for visual observation?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAntlia lists night visual observation as not recommended for this filter. It is designed for astrophotography of deep-sky objects that contain OIII emissions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Antlia 7nm OIII Prime filter parfocal with other Antlia filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Antlia 7nm OIII Prime filter has a specified thickness of \u003cstrong\u003e2mm +\/-0.05mm\u003c\/strong\u003e. The H-alpha and SII 7nm Prime filters have the same stated thickness, but Antlia does not give a parfocal specification for this series, so run a quick focus check when switching between filters, especially with very fast optical systems.\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\u003eOIII narrowband (7nm Prime series)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCentral Wavelength (CWL)\u003c\/td\u003e\n\u003ctd\u003e500.7nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandwidth (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\u003eOut of Band Blocking\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;OD4 (0.01%) @ 300-1000nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Size\u003c\/td\u003e\n\u003ctd\u003e36mm Round Unmounted\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 (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 arcsec\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEdge Treatment\u003c\/td\u003e\n\u003ctd\u003eEdge blackened\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\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\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 7nm OIII Prime Filter (36mm Unmounted)\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\nAntlia offers a 3-year warranty against delamination on this product.\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Antlia","offers":[{"title":"36mm Round Unmounted","offer_id":51932624650525,"sku":"ANT-OIII-7NM-RD36","price":221.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/antlia-src-opNCZ8wIwoAY4oAY_d9f5a144-e216-43a2-801c-f8505c3ee850.jpg?v=1792549997","url":"https:\/\/davidastro.com\/fr\/products\/antlia-7nm-narrowband-oiii-prime-filter","provider":"David Astro","version":"1.0","type":"link"}