{"product_id":"used-optolong-uhc-light-pollution-filter-1-27","title":"Used Optolong UHC Light Pollution Filter - 1.25\"","description":"\u003cp\u003eThis is an Optolong UHC light pollution filter in the 1.25\" format.  It is in excellent condition, clean surfaces, in its original jewel case.  \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch5\u003e\u003cbr\u003e\u003c\/h5\u003e\n\u003ch5\u003eDescription\u003c\/h5\u003e\n\u003cp\u003e\u003cspan\u003eThe UHC (Ultra High Contrast) broadband filter is designed to improve the visibility of various deep sky objects by selectively reducing the transmission of wavelengths of light pollutants.  Specifically, it reduces those produced by artificial lighting, including mercury vapor lamps, both high \u0026amp; 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\u003eThe UHC filter is highly transparent in the main nebula emission lines at OIII (496nm and 500nm), H-beta (486nm), NII (654nm and 658nm), H-alpha (656nm), as well as SII (672nm).  The UHC filter enhances the contrast and details for both visual and photographic purposes in areas with heavy light pollution.\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\u003eSuitable for color CCD cameras and unmodified DSLRs.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eThe UHC filter, with a narrower passband, provides higher contrast than the CLS filter. Thus it is more suitable for urban environments which suffer from severe light pollution.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eThe UHC filter has a substantial red passband and offers superb views for objects like the Orion Nebula (M42)\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eLight pollution filters 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, but without brightening the nebula.\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhich to Choose?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eL-Pro provides the broadest spectrum and most natural color. Suitable for imaging nebula and galaxy targets.\u003c\/li\u003e\n\u003cli\u003eUHC is not as broad spectrum, less natural color, but will block more stray light and skyglow than the L-Pro. Best suited to nebula targets, not broad spectrum targets like galaxies or clusters.\u003c\/li\u003e\n\u003cli\u003eL-Enhance is a narrow tri-band filter. Best suited to capturing dim nebula targets. Will decrease brightness of surrounding stars, allowing for more faint detail. \u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eIf you plan to use the filter to image a wide range of targets, the L-Pro is the most versatile. The L-Enhance will provide the most faint detail on emission nebula, and the UHC is a budget option in the middle.\u003c\/p\u003e\n\u003ch5\u003e\u003cspan\u003eSpecfications\u003c\/span\u003e\u003c\/h5\u003e\n\u003cp\u003e\u003cstrong\u003eTechnical Data\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eSchott substrate material\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eThickness 2.0 mm (1.25”\/2”\/36mm\/77mm\/82mm)\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eThickness 1.0 mm (Clip series)\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\u003eOptically polished to ensure accurate 1\/4 wavefront and \u0026lt;30 seconds parallelism over the both surfaces\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e95% transmission of main nebula emission lines (i.e. H-alpha 656nm, OIII 496nm and 500nm, SII 672nm and H-beta 486nm\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e0.1% transmission of off-band, specifically the major emission lines of artificial light pollution (i.e. Na 589nm, Hg 435nm and 578nm). Transmission of 0.1% is equivalent to OD3(Optical Density), where a high optical density value indicates very low transmission, and low optical density indicates high transmission.\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eCoating Parameter\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eMulti-layered anti-reflection coating\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eNon-cemented 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\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFilter Cell\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eUltra-thin filter cell minimizes vignetting by maximizing possible clear aperture (clear aperture is 26mm for 1.25”; 45mm for 2”)\u003c\/li\u003e\n\u003cli\u003eAerometal Material\u003c\/li\u003e\n\u003cli\u003ePrecise CNC Machining\u003c\/li\u003e\n\u003cli\u003eSand Blasting Process\u003c\/li\u003e\n\u003cli\u003eBlack Anodized Finish\u003c\/li\u003e\n\u003cli\u003eExtinction Treatment to Prevent Reflection\u003c\/li\u003e\n\u003cli\u003eLaser Engraving No Fading\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003ePackage\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003ePlastic PP Case\u003c\/li\u003e\n\u003cli\u003eImported High Pressure EVA Case Lining\u003c\/li\u003e\n\u003cli\u003eSilver Cardboard Box\u003c\/li\u003e\n\u003cli\u003eHigh Density Sponge Carton Lining\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eSizes\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eStandard 1.25”\u003c\/li\u003e\n\u003cli\u003eStandard 2”\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eClip Filters for crop sensors and full sensors\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eSpectral Curve (see image)\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eTransmits the major emission lines of nebulae\u003c\/strong\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eH-β 486.1nm, OIII 495.9nm, OIII 500.7nm, H-α 656.3nm\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eBlocks the major emission lines of artificial light pollution\u003c\/strong\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eMercury (Hg): 435.8nm, 546.1nm, 577nm, 578.1nm\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eSodium (Na): 598nm, 589.6nm, 615.4nm, 616.1nm\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"Optolong","offers":[{"title":"Default Title","offer_id":50138867859715,"sku":"U2610-KK-10101","price":34.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/462543754_998816185383495_3003646430733348290_n.jpg?v=1793823602","url":"https:\/\/milehighastro.com\/products\/used-optolong-uhc-light-pollution-filter-1-27","provider":"Mile High Astronomy","version":"1.0","type":"link"}