{"product_id":"optolong-sii-narrowband-telescope-filter-31mm","title":"Optolong SII Narrowband Telescope Filter - 31mm","description":"\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eThe SII-CCD 6.5nm Deep Sky Imaging Filter:\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThis filter \u003c\/span\u003eis an e\u003cspan\u003extra narrowband SII-CCD 6.5nm filter (Sulfur II for CCD) is designed for nebula observation allowing 6.5nm bandwidth of light centered on a wavelength of 672nm through, and reducing the transmission of certain wavelengths of light, specifically those produced by artificial light including mercury vapor, and both high and low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow).\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eMain Use and Performance\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eUse with H-alpha and OIII-CCD extra narrowband filters (SHO Set) for tricolor CCD astrophotography\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eNarrowband imaging with SHO set can be done with the moon up in heavy light pollution, so your equipment is not sitting dormant for several weeks\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eHubble look of images can be made by the combination of H-alpha, OIII-CCD and SII-CCD, such as the famous “Pillars of Creation” (M16 Eagle Nebula)\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eNarrowband filter do not eliminate the effects of light pollution or increase the object’s brightness. In many cases, they increase the contrast between nebula and night sky, not brightening the nebula.\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1594\/4815\/files\/Optolong_SII-CCD_6.5nm.jpg?v=1526318713\u0026amp;width=700\" alt=\"Optolong LRGB Ha SII \u0026amp; OIII Telescope Filter Kit-SII graph\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003ch2 itemprop=\"name\"\u003e\u003c\/h2\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eFeatures of the SII Filter:\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003eTechnical Data\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eSchott substrate material\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eThickness 2.0mm\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eSurface Quality: 60\/40 (Refer to MIL-O-13830)\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eFine-optically polished to ensure accurate 1\/4 wavefront and \u0026lt;30 seconds parallelism over the both surfaces\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003eThe SII filter has 80% transmission, the SII line is 672nm\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003ePrecision off-band blocking\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCoating Parameter\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eMulti-layers anti-reflection coating\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eNon-cementing optical substrate coating\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eElectron-beam gun evaporation with Ion-assisted deposition coating technology for durability and resistance to scratching, as well as stability on CWL(central wavelength) no deviation affected by temperature change\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003ePlanetary rotation system offers precision and homogeneity of coatings ensuring high value on transmission of pass-band and Optical density of off-band\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eFilter Cell\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eUltra-thin filter cell minimize vignetting by maximize possible clear aperture (clear aperture is 26mm for 1.25-inch; 45mm for 2-inch)\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eAerometal Material\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003ePrecise CNC Machining\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eSand Blasting Process\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eBlack Anodized Finish\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eExtinction Treatment to Prevent Reflection\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eLaser Engraving No Fading\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003c!-- split --\u003e\n\u003cul\u003e\n\u003cli\u003eSII 6.5nm CCD Deep Sky Imaging Filter\u003c\/li\u003e\n\u003cli\u003e80% peak transmission\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"Default Title","offer_id":67818666623209,"sku":"isx1793407156037","price":129.31,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0811\/1964\/1833\/files\/optolong-sii-narrowband-telescope-filter---31mm_1.jpg?v=1793407165","url":"https:\/\/engineerbootp.shop\/products\/optolong-sii-narrowband-telescope-filter-31mm","provider":"My Store","version":"1.0","type":"link"}