{"product_id":"player-one-1-25-sii-7nm-narrowband-filter","title":"Player One 1.25\" SII 7nm Narrowband Filter","description":"\u003cp\u003e\u003cstrong\u003eOverview.\u003c\/strong\u003e The Player One 1.25\" SII 7nm Narrowband Filter is an S-series singly-ionized sulfur (SII) emission-line filter for monochrome deep-sky astrophotography. It transmits a narrow 7nm ±0.5nm band on the SII emission of nebulae while rejecting the rest of the spectrum, recording the sulfur channel used in Hubble-palette imaging with high contrast even under moderate light pollution. The filter uses a high-quality optical glass substrate with a multi-layer composite coating and threads into standard 1.25\" filter mounts.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWho It's For.\u003c\/strong\u003e This filter suits imagers using monochrome cameras who want to capture the SII channel of emission nebulae and complete a tricolor (SHO) narrowband dataset, or continue imaging on moonlit and light-polluted nights.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eKey Features \u0026amp; Design.\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eNarrow 7nm passband:\u003c\/strong\u003e a 7nm ±0.5nm FWHM isolates the SII emission and rejects most skyglow and broadband light pollution.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep blocking:\u003c\/strong\u003e OD3 blocking (less than 0.1% off-band transmission) with NIR cutoff across 700–1100nm suppresses stray light.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHigh in-band throughput:\u003c\/strong\u003e approximately 90% peak transmittance preserves faint sulfur signal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMulti-layer composite coating:\u003c\/strong\u003e on a high-quality optical glass substrate for consistent response.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard 1.25\" format:\u003c\/strong\u003e M28.5×0.6 cell fits common 1.25\" filter wheels and drawers.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eOptical\/Mechanical Design.\u003c\/strong\u003e The filter passes a 7nm ±0.5nm FWHM band on the SII emission line and holds OD3 off-band blocking (\u0026lt;0.1% transmission) with the near-infrared blocked from 700–1100nm. Peak in-band transmittance is about 90%. Both surfaces are polished to 1\/4 lambda surface accuracy on a 2.0 ±0.03 mm optical glass substrate carrying a multi-layer composite coating. The anodized cell uses M28.5×0.6 (1.25\") threads and measures 7.5mm overall (5mm body plus 2.5mm thread).\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eRecommended Uses.\u003c\/strong\u003e Narrowband imaging of emission nebulae, HII regions, and supernova remnants; the SII channel in tricolor (SHO) Hubble-palette processing; and deep-sky capture during bright-moon or light-polluted conditions.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCompatibility \u0026amp; Accessory Notes.\u003c\/strong\u003e The M28.5×0.6 cell fits standard 1.25\" filter wheels, drawers, and 1.25\" nosepieces. It pairs with matching Player One 1.25\" Ha 7nm and OIII 7nm filters for a complete SHO set. Narrowband filters are intended for monochrome imaging cameras; on one-shot-color sensors the effective throughput is reduced.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eGood to Know Before You Order.\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eIndividual center wavelength:\u003c\/strong\u003e Player One does not publish a numeric center wavelength for this line on the product page, so it is not stated here.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eShipping weight:\u003c\/strong\u003e a packaged weight is not published by the manufacturer; contact us if you need it before ordering.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCamera type:\u003c\/strong\u003e narrowband results are strongest with monochrome cameras.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eFAQ.\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e No. The filter threads into any standard 1.25\" filter wheel, drawer, or nosepiece and needs no adjustment once installed.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill it help under light pollution?\u003c\/strong\u003e Yes. The 7nm passband rejects most broadband skyglow, so SII emission is recorded with strong contrast even from suburban skies.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use it with a color camera?\u003c\/strong\u003e It is designed for monochrome cameras; a one-shot-color sensor will pass the band but with reduced efficiency.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eBottom Line.\u003c\/strong\u003e A well-coated 7nm SII filter in the convenient 1.25\" format, the Player One 1.25\" SII 7nm records high-contrast sulfur-line detail and completes the SHO narrowband set.\u003c\/p\u003e","brand":"Player One Astronomy","offers":[{"title":"Default Title","offer_id":53834274078831,"sku":"SII7-125","price":180.6,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/HSO125-SET-600x600_e78520a6-0066-4dc4-abd4-b1879ec5b7cd.jpg?v=1784239555","url":"https:\/\/ontariotelescope.com\/products\/player-one-1-25-sii-7nm-narrowband-filter","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}