{"product_id":"svbony-sv220-1-25-3nm-h-alpha-oiii-dual-narrowband-filter","title":"SVBONY SV220 1.25″ 3nm H-Alpha \u0026 OIII Dual Narrowband Filter","description":"\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/w9198a-1_20250828164203_8293.jpg?v=1791669949\" alt=\"SVBONY SV220 1.25 inch 3nm H-alpha and OIII narrowband filter key visual\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe SVBONY SV220 1.25″ 3nm is a dual narrowband filter with two passbands of 3 ±1 nm FWHM centred on OIII (500.7 nm) and H-alpha (656.3 nm). Out-of-band light from 300 to 1050 nm is blocked to an average of OD5. The 2.0 mm substrate has a 26 mm clear aperture, 60\/40 surface quality, transmitted wavefront PV ≤ λ\/4 and 30″ parallelism, and is held in a 6061T aluminium cell (Φ31.75 x 7 mm) with a single M28.5 x 0.6 male thread. Net weight is 7 g.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is a good match if you image emission nebulae with a colour or mono camera from a heavily light-polluted site and want tighter passbands than a 7 nm filter for higher contrast and smaller stars.\u003c\/p\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/w9198a-2_20250828164216_5982.jpg?v=1791669949\" alt=\"SVBONY SV220 3nm filter narrow bandwidth feature panel\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e3 nm passbands:\u003c\/strong\u003e isolate the OIII and H-alpha lines more tightly than 7 nm filters, rejecting more sky glow.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHigh transmission:\u003c\/strong\u003e SVBONY specifies above 85% in both bands, which keeps exposure times practical.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOD5 average blocking:\u003c\/strong\u003e across 300–1050 nm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMinimal-halo multi-layer coating:\u003c\/strong\u003e designed to reduce glare and halos around bright stars.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e6061T aluminium cell:\u003c\/strong\u003e standard 1.25″ size with M28.5 x 0.6 thread.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/w9198a-3_20250828164237_5512.jpg?v=1791669949\" alt=\"SVBONY SV220 3nm filter high transmittance feature panel\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/w9198a-4_20250828164246_0236.jpg?v=1791669948\" alt=\"SVBONY SV220 3nm filter minimal halo coating panel\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eOptical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eNarrowing the passband from 7 nm to 3 nm passes the same emission-line signal from the nebula while admitting less than half the background sky light in each band. The result is a darker background and higher target contrast, at the cost of slightly fainter stars. Because the passbands are tight, the filter performs best on optics that are not extremely fast, where the steep light cone shifts the effective passband. The minimal-halo coating addresses the reflections that narrowband filters can produce around bright stars.\u003c\/p\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/w9198a-5_20250828164253_9868.jpg?v=1791669949\" alt=\"SVBONY SV220 3nm filter light pollution suppression panel\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/w9198a-6_20250828164301_3533.jpg?v=1791669948\" alt=\"SVBONY SV220 3nm filter detail panel\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eEmission nebulae from urban sites:\u003c\/strong\u003e H II regions, planetary nebulae and supernova remnants.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMoonlit nights:\u003c\/strong\u003e narrow passbands extend usable time around the full Moon.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBicolour imaging with a colour camera\u003c\/strong\u003e, or combined Ha+OIII data with a mono camera.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/w9198a-7_20250828164308_6046.jpg?v=1791669949\" alt=\"SVBONY SV220 3nm filter aluminium cell and M28.5 thread\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMounting:\u003c\/strong\u003e M28.5 x 0.6 male thread for 1.25″ nosepieces, filter wheels and drawers.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSensor size:\u003c\/strong\u003e the 26 mm clear aperture suits 1.25″-class sensors; the SV220 2″ 3nm covers larger sensors.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptics:\u003c\/strong\u003e narrowband passbands this tight are best matched to moderate focal ratios. Send us your telescope and camera and we will confirm the fit.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/w9198a-8_20250828164329_6732.jpg?v=1791669948\" alt=\"SVBONY SV220 3nm filter compatibility panel\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/w9198a-9_20250828164340_4707.jpg?v=1791669949\" alt=\"SVBONY SV220 3nm filter specifications panel\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eImaging filter:\u003c\/strong\u003e it has no application in visual observing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEmission targets:\u003c\/strong\u003e galaxies and reflection nebulae are broadband targets and gain little from it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExposure:\u003c\/strong\u003e tighter passbands mean longer sub-exposures than a 7 nm filter on the same target.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo. It threads into a 1.25″ nosepiece, filter wheel or drawer like any standard 1.25″ filter.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow does it differ from the SV220 7nm?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThe 3 nm passbands reject more sky background, so contrast is higher under bright skies; the 7 nm version collects signal faster and suits darker sites and faster optics.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it work with a colour camera?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes. On a colour sensor H-alpha records in the red pixels and OIII in the green and blue.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: a 1.25″ 3 nm H-alpha and OIII dual narrowband filter with OD5 blocking and a minimal-halo coating for high-contrast emission-nebula imaging under bright skies.\u003c\/p\u003e","brand":"SvBony","offers":[{"title":"Default Title","offer_id":67722286071919,"sku":"W9198A","price":170.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/1_20260209103830_3399.webp?v=1791670390","url":"https:\/\/ontariotelescope.com\/products\/svbony-sv220-1-25-3nm-h-alpha-oiii-dual-narrowband-filter","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}