{"product_id":"touptek-astro-puresight-a1-2inch-5nm-dual-narrowband-filter","title":"Touptek Astro PureSight A1  2inch 5nm Dual Narrowband Filter","description":"\u003ch1\u003eTouptek Astro 2inch Dual Narrowband Filter\u003c\/h1\u003e\n\u003cp\u003eToupTek Astro PureSight A1 Hα \u0026amp; OIII Dual Narrowband Filter is designed for deep-sky astrophotography under light-polluted skies. With a precise 5nm bandpass and optimization for fast optical systems, it enhances nebula contrast while effectively suppressing unwanted background light.\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0652\/6245\/2965\/files\/touptek-puresight-a1-dual-narrowband-filter-hero.webp?v=1776532833\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch2\u003eWhat is a Dual Narrowband Filter?\u003c\/h2\u003e\n\u003cp\u003eA dual narrowband filter is an astrophotography filter designed to isolate specific emission wavelengths, typically hydrogen-alpha (Hα) and oxygen III (OIII). By transmitting only these narrow spectral bands, the filter significantly enhances the visibility of emission nebulae while suppressing background light pollution.\u003c\/p\u003e\n\u003cp\u003eDual narrowband filters are widely used for deep-sky astrophotography, especially when imaging nebulae from urban or suburban locations where sky brightness can reduce contrast.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch2\u003eExceptional Image Purity\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eHalo-free performance with premium optical materials\u003c\/strong\u003e\u003c\/p\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e• High-purity fused silica substrate combined with IAD (Ion Assisted Deposition) coating for dense and uniform layers.\u003c\/div\u003e\n\u003cdiv\u003e• Advanced anti-reflection coatings significantly reduce internal reflections, halos, and ghosting.\u003c\/div\u003e\n\u003cdiv\u003e• ≥90% peak transmission, ≤30\" parallelism, and 60\/40 surface quality ensure a clean background and sharp stars.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cp\u003eCapture faint nebula details even from urban balconies or city skies.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003cdiv\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eProduct Name\u003c\/td\u003e\n\u003ctd\u003ePureSight A1 Hα \u0026amp; [OIII] Dual Narrowband 5nm F\/3.2\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTarget Emission Lines\u003c\/td\u003e\n\u003ctd\u003eHα 656.3nm \u0026amp; [OIII] 500.7nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFWHM\u003c\/td\u003e\n\u003ctd\u003e5.0nm ± 1.2 \/ 5.0nm ± 1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission Rate\u003c\/td\u003e\n\u003ctd\u003e≥90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOD\u003c\/td\u003e\n\u003ctd\u003e≥5 @ 200-1100nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eFused Silica\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eThickness\u003c\/td\u003e\n\u003ctd\u003e2.00mm ± 0.1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e≤ 30\"\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\u003eRecommended F-ratio\u003c\/td\u003e\n\u003ctd\u003e≥ F\/3.2\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating\u003c\/td\u003e\n\u003ctd\u003eIAD (Ion Deposition)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSize\u003c\/td\u003e\n\u003ctd\u003e2-inch (frame height: 5mm, thread height: 2mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eThread\u003c\/td\u003e\n\u003ctd\u003eM48×0.75\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFrame Material\u003c\/td\u003e\n\u003ctd\u003eAluminum Alloy\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eClear Aperture\u003c\/td\u003e\n\u003ctd\u003e43.9mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInstallation Direction\u003c\/td\u003e\n\u003ctd\u003eThreaded side toward the sensor\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch3\u003eIn the Box\u003c\/h3\u003e\n\u003cp\u003eTouptek 2inch dual band filter\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch3\u003eWarranty\u003c\/h3\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/astronomyplus.com\/pages\/touptek-warranty\" target=\"_blank\" rel=\"noopener\"\u003eTouptek's 2-Year Warranty\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Touptek","offers":[{"title":"Default Title","offer_id":48840672542949,"sku":"TOU-puresight-a1","price":405.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0652\/6245\/2965\/files\/touptek-dual-narrowband-filter-back.webp?v=1776533079","url":"https:\/\/astronomyplus.com\/products\/touptek-astro-puresight-a1-2inch-5nm-dual-narrowband-filter","provider":"Astronomy Plus – Telescopes \u0026 Astrophotography Canada","version":"1.0","type":"link"}