{"product_id":"optolong-s-ii-6-5nm-filter","title":"Optolong Sulphur-II 6.5nm Filter","description":"\u003cp\u003eUse the Optolong S-II 6.5nm filter with the H-alpha and OIII-CCD extra narrowband filters (SHO Set) for tricolor CCD astrophotography\u003cbr\u003eNarrowband imaging with a SHO filter set can be done with the moon up in heavy light pollution, allowing you to image much more frequently that would otherwise be possible.\u003cbr\u003eHubble palette images can be made by combining H-alpha, OIII-CCD and SII-CCD images into a color rendering, such as the famous \"Pillars of Creation\" (M16 Eagle Nebula)\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eFine-optically polishing for double-sides-- Ensure accurate λ\/4 wavefront and \u0026lt;30 seconds parallelism over the both surfaces\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eUltrasonic wave cleaning substrate with purified water to remove impurities and dust effectively\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eIRO source assisted coating - For durability and resistance to scratching, as well as stability on CWL (central wavelength).  No deviation from temperature change.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eConstant stringent quality testing processes - Each filter is tested by spectrophotometer and laser interferometer testing spectrum and wavefront to ensure market filter is qualified product\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eOptolong will spare no effort to serve our customer with outstanding quality products and best service!\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003c\/p\u003e\u003ch4\u003eSpecifications\u003c\/h4\u003e\u003cbr\u003e\n\u003cul\u003e\u003c\/ul\u003e\nCWL(center of wavelength): \u003cspan\u003eSII 671.6nm\u003c\/span\u003e\u003cbr\u003eFWHM: \u003cspan\u003eSII 6.5nm\u003c\/span\u003e\u003cbr\u003eTpeak: \u0026lt;85%\u003cbr\u003eOptical Density: OD 3\u003cbr\u003eSurface Quality: 60\/40\u003cbr\u003eTransmitted Wavefront RMS: λ\/4\u003cbr\u003eParallelism(arc sec): 30s","brand":"Optolong","offers":[{"title":"1.25\"","offer_id":30271896191056,"sku":"Optolong-S-II-6.5nm-1.25\"","price":203.0,"currency_code":"CAD","in_stock":true},{"title":"31mm","offer_id":30271896256592,"sku":"Optolong-S-II-6.5nm-31mm","price":246.0,"currency_code":"CAD","in_stock":true},{"title":"36mm","offer_id":30271896289360,"sku":"Optolong-S-II-6.5nm-36mm","price":253.0,"currency_code":"CAD","in_stock":true},{"title":"2\"","offer_id":30271896223824,"sku":"Optolong-S-II-6.5nm-2\"","price":318.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0224\/6770\/6960\/products\/optolong-filter-optolong-sulphur-ii-6-5nm-filter-12786566299728.jpg?v=1668533744","url":"https:\/\/telescopescanada.ca\/products\/optolong-s-ii-6-5nm-filter","provider":"Telescopes Canada","version":"1.0","type":"link"}