{"title":"Optolong Visual \u0026 Nebula Filters","description":"\u003cp\u003eH-beta and visual OIII filters for nebula observation.\u003c\/p\u003e","products":[{"product_id":"optolong-h-beta-filters-25nm","title":"Optolong H-beta Filters 25nm","description":"\u003cp data-mce-fragment=\"1\"\u003eThis premium Optolong Narrowband H-beta filter is designed for nebula observation allowing 25nm bandwidth of light centered on a wavelength of appr 490nm throughout, about halfway between the H-beta emission line and OIII. It also reduces 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). H-beta emits 486.1nm and it is a blue colored filter. Some images of planetary nebulae and supernova remnants are taken with H-alpha, H-beta and OIII filters. They show great structural details, but have natural colors, looking like an RGB image.\u003c\/p\u003e\n\u003ch2 data-mce-fragment=\"1\"\u003eMain Use and Performance\u003c\/h2\u003e\n\u003cp data-mce-fragment=\"1\"\u003eSuitable for visual observation on most emission nebulae, planetary nebulae and supernova remnants. Suitable for viewing on bright nebulae like M42 Orion Nebula in heavy light pollution. Use with a large aperture telescope under clear and dark viewing conditions with good seeing. Due to the fact that this filter will let through a larger amount of light around the OIII emission line, its main purpose is visual observations, however it can also be used with a small telescope for imaging deep sky objects.\u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\"\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, not brightening the nebula.\u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\"\u003e\u003cstrong data-mce-fragment=\"1\"\u003eWARNING:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\"\u003e\u003cstrong data-mce-fragment=\"1\"\u003eOptolong filters are not designed for solar observation. DO NOT LOOK AT THE SUN WITH ANY OPTOLONG FILTER as permanent eye damage will be the result.\u003c\/strong\u003e\u003c\/p\u003e\n\u003ch2 data-mce-fragment=\"1\"\u003eTechnical Data\u003c\/h2\u003e\n\u003cul data-mce-fragment=\"1\"\u003e\n\u003cli data-mce-fragment=\"1\"\u003eSchott substrate material\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eGlass thickness 2.0 mm (1.25”\/2”\/36mm)\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eSurface Quality: 60\/40 (Refer to MIL-O-13830)\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eFine-optically polished to ensure accurate 1\/4 wavefront and \u0026lt; 30 seconds parallelism over both surfaces\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003e90% transmission at major H-beta line 486.1nm, Partial transmission (appr 65-70%) of OIII line at 495.9nm.\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003ePrecision off-band blocking, specifically the major emission lines of artificial light pollution (i.e. Na 589nm, Hg 435nm and 578nm).\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2 data-mce-fragment=\"1\"\u003eFilter Cell\u003c\/h2\u003e\n\u003cul data-mce-fragment=\"1\"\u003e\n\u003cli data-mce-fragment=\"1\"\u003eUltra-thin filter cell minimise vignetting by maximising possible clear aperture (clear aperture is 26mm for 1.25” size and 45mm for 2” size)\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eAerometal Material\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003ePrecise CNC Machining\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eSand Blasting Process\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eBlack Anodized Finish\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eExtinction Treatment to Prevent Reflection\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eLaser Engraving No Fading\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2 data-mce-fragment=\"1\"\u003eAvailable Sizes\u003c\/h2\u003e\n\u003cul data-mce-fragment=\"1\"\u003e\n\u003cli data-mce-fragment=\"1\"\u003eStandard 1.25” \u0026amp; 2”\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eRound 36mm Unmounted\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2 data-mce-fragment=\"1\"\u003ePackaging\u003c\/h2\u003e\n\u003cul data-mce-fragment=\"1\"\u003e\n\u003cli data-mce-fragment=\"1\"\u003ePlastic PP Case\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eImported High Pressure EVA Case Lining\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eSilver Cardboard Box\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eHigh Density Sponge Carton Lining\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2 data-mce-fragment=\"1\"\u003eOptical Coating\u003c\/h2\u003e\n\u003cul data-mce-fragment=\"1\"\u003e\n\u003cli data-mce-fragment=\"1\"\u003eMulti-layer anti-reflection coating\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eNon-cementing optical substrate coating\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\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\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003ePlanetary rotation system offers precision and homogeneity of coatings ensuring high value on transmission of pass-band and Optical density of off-band. (Please note, \"planetary rotation system\" is a type of optical coating process and does not refer to the astronomical system describing the motion of the planets in our solar system.)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-mce-fragment=\"1\"\u003e\u003cem data-mce-fragment=\"1\"\u003e\u003cstrong data-mce-fragment=\"1\"\u003e\u003ca href=\"https:\/\/www.365astronomy.com\/image\/cache\/wp\/ij\/content\/Optolong-H-Beta-25nm-transmission.webp\" data-mce-fragment=\"1\" data-mce-href=\"https:\/\/www.365astronomy.com\/image\/cache\/wp\/ij\/content\/Optolong-H-Beta-25nm-transmission.webp\"\u003e\u003cimg alt=\"\" src=\"https:\/\/www.365astronomy.com\/image\/cache\/wp\/ij\/content\/Optolong-H-Beta-25nm-transmission.webp\" data-mce-fragment=\"1\" data-mce-src=\"https:\/\/www.365astronomy.com\/image\/cache\/wp\/ij\/content\/Optolong-H-Beta-25nm-transmission.webp\"\u003e\u003c\/a\u003e\u003c\/strong\u003e\u003c\/em\u003e\u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\"\u003eThe Major Emission Lines of Nebulae: H-α 656.3nm, H-β486.1nm, OIII 495.9nm, OIII 500.7nm \u003cbr data-mce-fragment=\"1\"\u003eThe Major Emission Lines of Artificial Light Pollution: Hg 435.8nm, 546.1nm, 577nm, 578.1nm, Na 598nm, 589.6nm, 615.4nm, 616.1nm\u003c\/p\u003e","brand":"Optolong","offers":[{"title":"1.25\"","offer_id":42296370233521,"sku":null,"price":67.99,"currency_code":"GBP","in_stock":true},{"title":"2\"","offer_id":42296370266289,"sku":null,"price":106.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0523\/1650\/4241\/files\/optolong-h-beta-filters-25nm-477844.webp?v=1718364506"},{"product_id":"optolong-oiii-25nm-filter","title":"Optolong OIII 25nm Filter","description":"\u003ch3\u003eThis premium Optolong Narrowband OIII filter is designed for nebula observation allowing 25nm bandwidth of light centred on a wavelength of 500nm through, which corresponds to OIII emission lines, 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. sky glow).\u003c\/h3\u003e\n\u003cp\u003eOIII emits 495.9nm and 500.7nm and it is a blue-green coloured filter. Many images of planetary nebulae and supernova remnants are taken only with H-alpha and OIII filters. They show great structural details, but have natural colours, looking like an RGB image.\u003c\/p\u003e\n\u003ch2\u003eMain Use and Performance\u003c\/h2\u003e\n\u003cp\u003eSuitable for visual observation on most emission nebulae, planetary nebulae and supernova remnants. Suitable for viewing on bright nebulae like M42 Orion Nebula in heavy light pollution. Use with a large aperture telescope under clear and dark viewing conditions with good seeing. Due to the fact that this filter will let through a larger amount of light around the OIII emission line, its main purpose is visual observations, however it can also be used with a small telescope for imaging deep sky objects.\u003c\/p\u003e\n\u003cp\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, not brightening the nebula.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWARNING:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eOptolong filters are not designed for solar observation. DO NOT LOOK AT THE SUN WITH ANY OPTOLONG FILTER as permanent eye damage will be the result.\u003c\/strong\u003e\u003c\/p\u003e\n\u003ch2\u003eTechnical Data\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eSchott substrate material\u003c\/li\u003e\n\u003cli\u003eGlass thickness 2.0 mm (1.25”\/2”\/36mm)\u003c\/li\u003e\n\u003cli\u003eSurface Quality: 60\/40 (Refer to MIL-O-13830)\u003c\/li\u003e\n\u003cli\u003eFine-optically polished to ensure accurate 1\/4 wave front and \u0026lt; 30 seconds parallelism over both surfaces\u003c\/li\u003e\n\u003cli\u003e90% transmission at major OIII line 495.9nm and 500.7nm\u003c\/li\u003e\n\u003cli\u003ePrecision off-band blocking, specifically the major emission lines of artificial light pollution (i.e. Na 589nm, Hg 435nm and 578nm).\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eFilter Cell\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eUltra-thin filter cell minimise vignetting by maximising possible clear aperture (clear aperture is 26mm for 1.25” size and 45mm for 2” size)\u003c\/li\u003e\n\u003cli\u003eAero metal 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\u003ch2\u003eAvailable Sizes\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eStandard 1.25” \u0026amp; 2”\u003c\/li\u003e\n\u003cli\u003eRound 36mm Unmounted\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003ePackaging\u003c\/h2\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\u003ch2\u003eOptical Coating\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eMulti-layer anti-reflection coating\u003c\/li\u003e\n\u003cli\u003eNon-cementing optical substrate coating\u003c\/li\u003e\n\u003cli\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\/li\u003e\n\u003cli\u003ePlanetary rotation system offers precision and homogeneity of coatings ensuring high value on transmission of pass-band and Optical density of off-band. (Please note, \"planetary rotation system\" is a type of optical coating process and does not refer to the astronomical system describing the motion of the planets in our solar system.)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/www.365astronomy.com\/image\/cache\/wp\/iJ\/content\/Optolong-OIII-25nm-visual-nebulosity-filter-transmission.webp\"\u003e\u003cimg src=\"https:\/\/www.365astronomy.com\/image\/cache\/wp\/iJ\/content\/Optolong-OIII-25nm-visual-nebulosity-filter-transmission.webp\" alt=\"\"\u003e\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003eThe Major Emission Lines of Nebulae: H-α 656.3nm, H-β486.1nm, OIII 495.9nm, OIII 500.7nm \u003cbr\u003eThe Major Emission Lines of Artificial Light Pollution: Hg 435.8nm, 546.1nm, 577nm, 578.1nm, Na 598nm, 589.6nm, 615.4nm, 616.1nm\u003c\/p\u003e\n\u003ch1 class=\"title page-title\" data-mce-fragment=\"1\"\u003e\u003cbr\u003e\u003c\/h1\u003e\n\u003ch1 class=\"title page-title\" data-mce-fragment=\"1\"\u003e\n\u003cimg src=\"https:\/\/www.365astronomy.com\/image\/cache\/wp\/iJ\/content\/Optolong-OIII-25nm-visual-nebulosity-filter-NGC2244-Rosette-Nebula.webp\" data-mce-fragment=\"1\"\u003e\u003cbr\u003e\n\u003c\/h1\u003e","brand":"Optolong","offers":[{"title":"1.25\"","offer_id":54907357626744,"sku":"10211125","price":91.0,"currency_code":"GBP","in_stock":true},{"title":"2\"","offer_id":54907357659512,"sku":null,"price":54.0,"currency_code":"GBP","in_stock":false},{"title":"36mm Unmounted Round","offer_id":54907357692280,"sku":null,"price":54.0,"currency_code":"GBP","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0523\/1650\/4241\/files\/optolong-oiii-25nm-filter-205692.webp?v=1718364480"}],"url":"https:\/\/www.darkclearskies.co.uk\/collections\/optolong-hub-visual-nebula.oembed","provider":"Dark Clear Skies ","version":"1.0","type":"link"}