{"product_id":"optolong-l-ultimate-dual-narrowband-filter-2","title":"Optolong L-Ultimate Dual Narrowband Filter - 2\"","description":"The Optolong L-Ultimate dual narrowband filter is designed to drastically reduce the effect of light pollution and capture a very specific wavelength of light emitted from deep space emission and planetary nebula. Its two ultra-narrow 3 nm passing bands isolate the nebulae emissions in Ha (red) as well as OIII (green-blue).\u003cbr\u003e\u003cbr\u003eThis effectively means local light pollution is much less significant and even imaging during a full moon is possible too as all other wavelengths outside of the specific Ha and OIII signal are blocked from entering the camera. The L-Ultimate filter is literally the ultimate filter for astrophotography under urban light polluted skies.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eFeatures:\u003c\/strong\u003e\u003cbr\u003e\n\u003cul\u003e\n\u003cli\u003eBlocks the artificial light from mercury vapour lamps, both high and low pressure sodium vapour lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (skyglow).\u003c\/li\u003e\n\u003cli\u003eMaximum transmission of the main nebula emission lines at OIII (496 nm and 500 nm) and H-alpha (656 nm)\u003c\/li\u003e\n\u003cli\u003eTwo transmission bands with a bandpass of 3nm each\u003c\/li\u003e\n\u003cli\u003eDesigned mainly for astrophotography with color cameras\u003c\/li\u003e\n\u003cli\u003eAlso helpful with monochrome cameras, no need to change filters for catching both lines\u003c\/li\u003e\n\u003cli\u003eIdeal for urban areas with extreme light pollution\u003c\/li\u003e\n\u003cli\u003eIt incorporates an IR\/UV cut filter that is necessary in astrophotography, especially for astronomy cameras that are sensitive to the infrared radiation.\u003c\/li\u003e\n\u003cli\u003eUltra-thin filter cell to maximise the compatibility with most filter wheels.\u003c\/li\u003e\n\u003cli\u003eMulti-layered anti-reflection coating\u003c\/li\u003e\n\u003cli\u003eNo obvious halo around bright stars\u003c\/li\u003e\n\u003cli\u003eCell in an aerometal material, CNC machined, sand blasted, black anodized and laser engraved\u003c\/li\u003e\n\u003cli\u003eIncludes a PP plastic case, high pressure EVA case lining\u003c\/li\u003e\n\u003c\/ul\u003e\nThe interferential coating is deposited on the substrate using electron-beam gun evaporation with Ion-assisted deposition coating technology. This essentially increases the filter durability and resistance to scratching, as well as stability on CWL (central wavelength) and no deviation affected by temperature changes. \u003cbr\u003e\u003cbr\u003eThe planetary rotation system offers precision and homogeneity of coatings ensuring high transmission of pass-band and high optical density off-band.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eSpec:\u003c\/strong\u003e\u003cbr\u003e\n\u003cul\u003e\n\u003cli\u003eTransmitted lines: OIII (500.7 nm), H-alpha (656.3 nm)\u003c\/li\u003e\n\u003cli\u003eFWHM: 3nm\u003c\/li\u003e\n\u003cli\u003eSuitable for: 2\" Filter threads\u003c\/li\u003e\n\u003cli\u003eBlocking range: 300 - 1000 nm (UV\/IR cut)\u003c\/li\u003e\n\u003cli\u003eBlocking: \u0026gt;OD4\u003c\/li\u003e\n\u003cli\u003eSubstrate: Optical glass made by Schott\u003c\/li\u003e\n\u003cli\u003eSubstrate thickness: 2mm\u003c\/li\u003e\n\u003cli\u003eSurface quality: 60\/40\u003c\/li\u003e\n\u003cli\u003eOptical flatness: λ\/4 rms\u003c\/li\u003e\n\u003cli\u003eParallelism: 30 arc sec\u003c\/li\u003e\n\u003cli\u003eAR coating: Multi layer\u003c\/li\u003e\n\u003cli\u003eCell: Aluminum, black anodized\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cbr\u003e\u003cem\u003eWhats included:\u003c\/em\u003e\u003cbr\u003e\n\u003col\u003e\n\u003cli\u003eL-Ultimate Filter\u003c\/li\u003e\n\u003cli\u003eProtective box, foam lined\u003c\/li\u003e\n\u003c\/ol\u003e","brand":"Optolong","offers":[{"title":"Default Title","offer_id":43659544494323,"sku":"L-ULTIMATE2","price":310.0,"currency_code":"CHF","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0596\/1924\/6275\/products\/Optolong-L-Ultimate-Narrowband-Filter.jpg?v=1677184128","url":"https:\/\/www.horizonastronomy.ie\/en-ch\/products\/optolong-l-ultimate-dual-narrowband-filter-2","provider":"Horizon Astronomy • Telescope Center","version":"1.0","type":"link"}