{"product_id":"svbony-1-25-uhc-light-pollution-filter","title":"SVBONY 1.25″ UHC Light Pollution Filter","description":"\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/6368834932617211706668990.jpg?v=1791669897\" alt=\"SVBONY UHC light pollution 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 F9131A is a 1.25″ UHC (Ultra High Contrast) filter in a standard M28.5 x 0.6 cell. It is a narrower-passband light pollution filter than a CLS: it reduces light from mercury-vapour and sodium-vapour lamps and the natural oxygen airglow of the atmosphere, while passing the emission lines of nebulae. The result is a darker sky background and higher contrast on emission and planetary nebulae. The coated optical glass is 1.85 mm thick in an aluminium frame, and the filter ships in a transparent storage case.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is a good match if you observe or image emission nebulae from urban or suburban skies through a 1.25″ eyepiece or imaging train and want the background darkened noticeably more than a broadband filter would.\u003c\/p\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/f9131a_20250807111258_9145.jpg?v=1791669899\" alt=\"SVBONY F9131A 1.25″ UHC light pollution filter for nebula observing and imaging\" 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\u003eUltra-high contrast passband:\u003c\/strong\u003e selectively reduces artificial-light wavelengths so emission nebulae stand out from the sky.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDarker background:\u003c\/strong\u003e SVBONY rates the sky background darker and nebula contrast higher than with typical broadband filters.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptical glass in an aluminium frame:\u003c\/strong\u003e 1.85 mm coated substrate built for frequent use.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard 1.25″ cell:\u003c\/strong\u003e M28.5 x 0.6 thread fits most 1.25″ eyepieces, diagonals and accessories.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStorage:\u003c\/strong\u003e supplied in a transparent case.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/6387029079471920178388140.jpg?v=1791669898\" alt=\"SVBONY UHC filter nebula contrast and light pollution blocking 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\u003eVisual observing of emission nebulae:\u003c\/strong\u003e the Orion, Lagoon, Swan and Veil nebulae from suburban sites.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePlanetary nebulae:\u003c\/strong\u003e the Ring and Dumbbell show more clearly against a darkened background.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eColour imaging under bright skies:\u003c\/strong\u003e more contrast on emission targets with a 1.25″ imaging train.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/1_20260304091845_2351.webp?v=1791669898\" alt=\"SVBONY UHC light pollution filter for emission nebula observing and imaging\" 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\/2_20260304091847_9948.webp?v=1791669898\" alt=\"SVBONY UHC light pollution filter for emission nebula observing and imaging\" 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\u003eThread:\u003c\/strong\u003e M28.5 x 0.6, the standard 1.25″ filter thread on eyepieces, diagonals and nosepieces.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOther sizes:\u003c\/strong\u003e SVBONY also makes this filter in 2″ (F9131B, M48 x 0.75) and as a Canon EOS-C clip-in (F9131D).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUHC vs CLS:\u003c\/strong\u003e the UHC has the narrower passband and suits brighter skies; SVBONY's CLS filter is the wider option for less light-polluted sites.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/3_20260304091850_2188.webp?v=1791669898\" alt=\"SVBONY UHC light pollution filter for emission nebula observing and imaging\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWhat's in the Box\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e1 x 1.25″ UHC filter (F9131A)\u003c\/li\u003e\n\u003cli\u003e1 x transparent storage case\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBest on emission objects:\u003c\/strong\u003e galaxies and star clusters are broadband targets and gain little from a UHC filter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDimmer stars and colour shift:\u003c\/strong\u003e the narrower passband dims stars visually and gives images a colour cast that is corrected in processing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e SVBONY does not publish a weight for this filter.\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 the filter thread at the bottom of a 1.25″ eyepiece or the nosepiece of a diagonal.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs it for visual use or imaging?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eBoth. SVBONY presents it for visual observing and astrophotography.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eShould I choose UHC or CLS?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eUnder brighter suburban or city skies the UHC gives more contrast. Under moderately dark skies the wider CLS keeps more starlight. Get in touch if you want help choosing.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: a 1.25″ M28.5 UHC filter that darkens light-polluted skies and lifts emission and planetary nebulae, for visual observing and imaging through standard 1.25″ gear.\u003c\/p\u003e","brand":"SvBony","offers":[{"title":"1.25″","offer_id":67722179149935,"sku":"F9131A","price":34.2,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/f9131a_20250807111258_9145.jpg?v=1791669899","url":"https:\/\/ontariotelescope.com\/products\/svbony-1-25-uhc-light-pollution-filter","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}