{"title":"Optolong","description":"\u003cp style=\"text-align: center;\"\u003eHorizon Astronomy is an Authorised OPTOLONG Retailer for Europe. If you are looking for a specific Optolong product not listed below please \u003ca href=\"https:\/\/www.horizonastronomy.ie\/pages\/contact-us\" target=\"_blank\" rel=\"noopener\"\u003econtact us here\u003c\/a\u003e\u003ca href=\"https:\/\/www.horizonastronomy.ie\/en-de\/pages\/contact-us\" rel=\"noopener\" target=\"_blank\"\u003e\u003c\/a\u003e - and we would be happy to help you.\u003c\/p\u003e","products":[{"product_id":"optolong-l-extreme-deep-sky-light-pollution-filter-1-25","title":"Optolong L-eXtreme Dual Narrowband Filter - 1.25\"","description":"\u003cp\u003e\u003cspan data-mce-fragment=\"1\"\u003eThe L-eXtreme Filter is \u003c\/span\u003e\u003cspan data-mce-fragment=\"1\"\u003eperfect for deep sky nebula photography from the city as it uses much tighter narrowband limits - blocking out unwanted glow from the city. The relentless spread or urbanization and its associated light pollution have become a big problem for all amateur astro photographers around the world. One solution is to purchase a Mono camera but this can be expensive and might also require the purchase of several types of narrowband filters and a filter wheel.\u003c\/span\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eThese filters open up a whole new opportunity for fast newtonian telescopes, double-lens ED refractors or even achromats, allowing for extremely detailed and high class astronomical images even from heavy light polluted cities as it blocks out all artificial light pollution sources as it is a dual narrow bandpass filter, only allowing for the wavelengths of O-III and H-Alpha. This filter is fast bcoming a must have item for serious Astro-imagers using OSC cameras.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eThe L-eXtreme is a two 7NM narrow bandpass filter which can be used with one-shot color cameras like DSLRs (digital SLR), color CMOS and monochrome CCD cameras. The convenience and cost-effectiveness of this filter allows amateurs to photograph rich emission type nebulas, even in bright, heavily light-polluted skies. The L-eXtreme filter is the best choice for fast optical systems as it isolates the H-Alpha and Oxygen III nebula emission lines so that the contrast and signal-to-noise ratio between these are maximized.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eL-eXtreme has a multiple anti-reflective coatings on the optical substrate. The L-eXtreme filter uses a precision coating based on ion deposition coating technology. This ensures durability and scratch resistance as well as stability on the CWL (central wavelength), which is not affected by temperature changes. Absolute precision of the coatings as well as maximum values for transmission in the passband and optical density in the off-band range are guaranteed for all filters.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cem\u003eIMPORTANT WARNING: These nebula filters are NOT designed for observation of the Sun. Do not use this filter to look at the Sun as serious eye damage, blindness as well as damage to equipment may result.\u003c\/em\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cb\u003eFilter Details:\u003c\/b\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eProfessional photographic filter for astronomy\u003c\/li\u003e\n\u003cli\u003eImproves deep sky emission nebula photography\u003c\/li\u003e\n\u003cli\u003eBest choice for extreme light pollution suppression\u003c\/li\u003e\n\u003cli\u003eFor taking pictures also from highly light-polluted areas\u003c\/li\u003e\n\u003cli\u003eDual-narrow-band filter with high transmission for O-III and H-Alpha lines\u003c\/li\u003e\n\u003cli\u003eDoes not require very large or extremely expensive telescopes\u003c\/li\u003e\n\u003cli\u003eExcellent results also with fast inexpensive newtonian telescopes, double-lens ED refractors or even achromats\u003c\/li\u003e\n\u003cli\u003eL-eXtreme filter is the better choice for fast systems at a competitive price\u003c\/li\u003e\n\u003cli\u003eCMOS colour cameras can deliver an image quality that comes close to CCD monochrome cameras\u003c\/li\u003e\n\u003cli\u003eFilter diameter: 1.25 inches \/ 31.7 mm\u003c\/li\u003e\n\u003cli\u003eConnecting thread: M28x0.6mm\u003c\/li\u003e\n\u003cli\u003eSelected optical glass material\u003c\/li\u003e\n\u003cli\u003eSpectrum: 300-1000nm\u003c\/li\u003e\n\u003cli\u003eOff-Band Blocking: \u0026gt; 99 %\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 wavefront and highest parallelism over the both surfaces\u003c\/li\u003e\n\u003cli\u003eHigh transmission at major nebula emission lines (i.e. H-alpha 656nm and OIII 496nm \u0026amp; 500nm)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cem\u003eWhats included:\u003c\/em\u003e\u003cbr data-mce-fragment=\"1\"\u003e\n\u003col\u003e\n\u003cli\u003eL-eXtreme filter (designed for 1.25\" optics)\u003c\/li\u003e\n\u003cli\u003eDust protection box\u003c\/li\u003e\n\u003cli\u003eTechnical Data\u003c\/li\u003e\n\u003c\/ol\u003e","brand":"Optolong","offers":[{"title":"Default Title","offer_id":40683481432259,"sku":"L-eXtreme1","price":259.0,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0596\/1924\/6275\/products\/OptolongL-ExtremeFilter125_6.jpg?v=1631716652"},{"product_id":"optolong-l-extreme-deep-sky-light-pollution-filter-2","title":"Optolong L-eXtreme Dual Narrowband Filter - 2\"","description":"\u003cp\u003eL-eXtreme Filter is absolutely perfect for deep sky nebula photography from the city as it uses much tighter narrowband limits. The relentless spread or urbanization and its associated light pollution have become a big problem for all amateur astro photographers around the world. One solution is to purchase a Mono camere but this can be extremely expensive and might include the purchase of several types of narrowband filters and a filter wheel.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eThese filters open up a whole new opportunity for fast newtonian telescopes, double-lens ED refractors or even achromats, allowing for extremely detailed and high class astronomical images even from heavy light polluted cities as it blocks out all artificial light pollution sources as it is a dual narrow bandpass filter, only allowing for the wavelengths of O-III and H-Alpha. This filter is fast bcoming a must have item for serious Astro-imagers using OSC cameras.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eThe L-eXtreme is a two 7NM narrow bandpass filter which can be used with one-shot color cameras like DSLRs (digital SLR), color CMOS and monochrome CCD cameras. The convenience and cost-effectiveness of this filter allows amateurs to photograph rich emission type nebulas, even in bright, heavily light-polluted skies. The L-eXtreme filter is the best choice for fast optical systems as it isolates the H-Alpha and Oxygen III nebula emission lines so that the contrast and signal-to-noise ratio between these are maximized.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eL-eXtreme has a multiple anti-reflective coatings on the optical substrate. The L-eXtreme filter uses a precision coating based on ion deposition coating technology. This ensures durability and scratch resistance as well as stability on the CWL (central wavelength), which is not affected by temperature changes. Absolute precision of the coatings as well as maximum values for transmission in the passband and optical density in the off-band range are guaranteed for all filters.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cem\u003eIMPORTANT WARNING: These nebula filters are NOT designed for observation of the Sun. Do not use this filter to look at the Sun as serious eye damage, blindness as well as damage to equipment may result.\u003c\/em\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cb\u003eFilter Details:\u003c\/b\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eProfessional photographic filter for astronomy\u003c\/li\u003e\n\u003cli\u003eImproves deep sky emission nebula photography\u003c\/li\u003e\n\u003cli\u003eBest choice for extreme light pollution suppression\u003c\/li\u003e\n\u003cli\u003eFor taking pictures also from highly light-polluted areas\u003c\/li\u003e\n\u003cli\u003eDual-narrow-band filter with high transmission for O-III and H-Alpha lines\u003c\/li\u003e\n\u003cli\u003eDoes not require very large or extremely expensive telescopes\u003c\/li\u003e\n\u003cli\u003eExcellent results also with fast inexpensive newtonian telescopes, double-lens ED refractors or even achromats\u003c\/li\u003e\n\u003cli\u003eL-eXtreme filter is the better choice for fast systems at a competitive price\u003c\/li\u003e\n\u003cli\u003eCMOS colour cameras can deliver an image quality that comes close to CCD monochrome cameras\u003c\/li\u003e\n\u003cli\u003eFilter diameter: 1.25 inches \/ 31.7 mm\u003c\/li\u003e\n\u003cli\u003eConnecting thread: M28x0.6mm\u003c\/li\u003e\n\u003cli\u003eSelected optical glass material\u003c\/li\u003e\n\u003cli\u003eSpectrum: 300-1000nm\u003c\/li\u003e\n\u003cli\u003eOff-Band Blocking: \u0026gt; 99 %\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 wavefront and highest parallelism over the both surfaces\u003c\/li\u003e\n\u003cli\u003eHigh transmission at major nebula emission lines (i.e. H-alpha 656nm and OIII 496nm \u0026amp; 500nm)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cem\u003eWhats included:\u003c\/em\u003e\u003cbr data-mce-fragment=\"1\"\u003e\n\u003col\u003e\n\u003cli\u003eL-eXtreme filter (designed for 1.25\" optics)\u003c\/li\u003e\n\u003cli\u003eDust protection box\u003c\/li\u003e\n\u003cli\u003eTechnical Data\u003c\/li\u003e\n\u003c\/ol\u003e","brand":"Optolong","offers":[{"title":"Default Title","offer_id":40683519803587,"sku":"0310170","price":319.0,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0596\/1924\/6275\/products\/OptolongL-ExtremeFilter2_2.jpg?v=1631718336"},{"product_id":"optolong-l-enhance-deep-sky-light-pollution-filter-2","title":"Optolong L-eNhance Dual Narrowband Filter - 2\"","description":"The L-enhance Filter is a Tri-band filter, perfect for deep sky nebula photography from the city as it uses tight narrowband limits - blocking out unwanted glow from the city. The relentless spread or urbanization and its associated light pollution have become a big problem for all amateur astro photographers around the world. One solution is to purchase a Mono camera but this can be expensive and might also require the purchase of several types of narrowband filters and a filter wheel.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eThese filters open up a whole new opportunity for fast newtonian telescopes, double-lens ED refractors or even achromats, allowing for extremely detailed and high class astronomical images even from heavy light polluted cities as it blocks out all artificial light pollution sources as it is a Tri-bandpass filter, only allowing for the wavelengths of O-III, H-Beta \u0026amp; H-Alpha.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eL-eNhance provides an economical and practical solution for amateurs using DSLR or color CMOS and monochrome CCD cameras. The convenience and cost-effectiveness of this filter allows amateurs to take detailed astronomical images, even in bright, heavily light-polluted areas thanks to its maximum transmission lines of up to 90%. The narrow bandpass for the wavelengths of O-III, H-Beta and H-Alpha really help control the impact from light polluted skies.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eL-eNhance has a multiple anti-reflective coating on the optical substrate which uses a precision coating based on ion deposition coating technology. This ensures durability and scratch resistance as well as stability on the CWL (central wavelength), which is not affected by temperature changes.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cem\u003eIMPORTANT WARNING: These nebula filters are NOT designed for observation of the Sun. Do not use this filter to look at the Sun as serious eye damage, blindness as well as damage to equipment may result.\u003c\/em\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cstrong\u003eFeatures:\u003c\/strong\u003e\u003cbr data-mce-fragment=\"1\"\u003e\n\u003cul\u003e\n\u003cli\u003eProfessional photographic filter for astronomy\u003c\/li\u003e\n\u003cli\u003eImproves deep sky emission nebula photography\u003c\/li\u003e\n\u003cli\u003eBest choice for enhanced light pollution suppression\u003c\/li\u003e\n\u003cli\u003eFor taking pictures also from highly light polluted areas\u003c\/li\u003e\n\u003cli\u003eTri-band filter with high transmission for O-III, H-Beta and H-Alpha lines\u003c\/li\u003e\n\u003cli\u003eDoes not require very large or extremely expensive telescopes\u003c\/li\u003e\n\u003cli\u003eExcellent results also with inexpensive newtonian telescopes, double-lens ED refractors or even achromats\u003c\/li\u003e\n\u003cli\u003eCMOS colour cameras can deliver an image quality that comes close to CCD monochrome cameras\u003c\/li\u003e\n\u003cli\u003eBalanced colour for a natural image\u003c\/li\u003e\n\u003cli\u003eFilter diameter: 2 inch\u003c\/li\u003e\n\u003cli\u003eConnecting thread: M28,5 x 0,6mm (Eyepiece thread 1.25 inch)\u003c\/li\u003e\n\u003cli\u003eSelected optical glass material\u003c\/li\u003e\n\u003cli\u003eSpectrum: 300-1000nm\u003c\/li\u003e\n\u003cli\u003eOff-Band Blocking: \u0026gt; 99%\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 wavefront and highest parallelism over the both surfaces\u003c\/li\u003e\n\u003cli\u003eHigh transmission at major nebula emission lines (i.e. H-alpha 656nm, OIII 496nm\u0026amp;500nm and H-beta 486nm).\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cem\u003eWhats included:\u003c\/em\u003e\u003cbr data-mce-fragment=\"1\"\u003e\n\u003col\u003e\n\u003cli\u003eL-eNhance 2\" filter\u003c\/li\u003e\n\u003cli\u003eDust protection box\u003c\/li\u003e\n\u003c\/ol\u003e","brand":"Optolong","offers":[{"title":"Default Title","offer_id":40683842339011,"sku":"L-eXtreme2","price":350.0,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0596\/1924\/6275\/products\/OptolongL-Enhance2_2.jpg?v=1631720499"},{"product_id":"optolong-l-pro-deep-sky-light-pollution-filter-1-25","title":"Optolong L-Pro Deep Sky Light Pollution Filter - 1.25\"","description":"The L-Pro Filter is the best choice for light pollution suppression and allows astrophotos to be taken of broadband emission objects such as galaxies, reflection nebulae and globular star clusters.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eThe relentless spread or urbanization and its associated light pollution have become a big problem for all amateur astro photographers around the world. One solution is to purchase a Mono camera but this can be expensive and might also require the purchase of several types of narrowband filters and a filter wheel.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eL-Pro is a multi-bandpass filter which offers much better color balance by maximizing the transmission band. The balanced transmission allows astrophotos to be taken with minimal color cast to broadband emission objects such as galaxies, reflection nebulae and globular star clusters. L-Pro remains the best choice for viewing or photographing broadband targets in light polluted areas.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eL-Pro (L-Professional) filter is designed to improve the visibility of various deepsky objects by selectively reducing the transmission of wavelengths of light pollutants, specifically those produced by artificial lights such as 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). Together with the highly transparent main emission lines at OIII (496nm and 500nm), H-beta (486nm), NII (654nm and 658nm), H-alpha (656nm) as well as SII (672nm), the filter is suitable for enhancing the contrast and details for both visual and photograghic purpose at sub-rural areas with heavy light pollution.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eL-Pro has a multiple anti-reflective coating on the optical substrate and uses a precision coating based on ion deposition coating technology. This ensures durability and scratch resistance as well as stability on the CWL (central wavelength), which is not affected by temperature changes.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cem\u003eIMPORTANT WARNING: These nebula filters are NOT designed for observation of the Sun. Do not use this filter to look at the Sun as serious eye damage, blindness as well as damage to equipment may result.\u003c\/em\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cstrong\u003eFeatures:\u003c\/strong\u003e\u003cbr data-mce-fragment=\"1\"\u003e\n\u003cul\u003e\n\u003cli\u003eProfessional visual and photographic filter for astronomy\u003c\/li\u003e\n\u003cli\u003eImproves deep sky nebula constellation photography\u003c\/li\u003e\n\u003cli\u003eBest choice for broadband light pollution suppression\u003c\/li\u003e\n\u003cli\u003eFilter diameter: 1.25 inch \/ 31.7mm\u003c\/li\u003e\n\u003cli\u003eConnecting thread: M28.5 x 0.6mm (Eyepiece thread 1.25 inch)\u003c\/li\u003e\n\u003cli\u003eSelected optical glass material\u003c\/li\u003e\n\u003cli\u003eSpectrum: 380-750nm\u003c\/li\u003e\n\u003cli\u003eSurface Quality: 60\/40 (Refer to MIL-O-13830)\u003c\/li\u003e\n\u003cli\u003eFine-optically polished glass to ensure accurate 1\/4 wavefront and highest parallelism over the both surfaces\u003c\/li\u003e\n\u003cli\u003eHigh transmission at major nebula emission lines (i.e. H-alpha 656nm, OIII 496nm\u0026amp;500nm, SII 672nm and H-beta 486nm)\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\u003cbr data-mce-fragment=\"1\"\u003e\u003cem\u003eWhats included:\u003c\/em\u003e\u003cbr data-mce-fragment=\"1\"\u003e\n\u003col\u003e\n\u003cli\u003eL-Pro filter (1.25\")\u003c\/li\u003e\n\u003cli\u003eDust protection box\u003c\/li\u003e\n\u003c\/ol\u003e","brand":"Optolong","offers":[{"title":"Default Title","offer_id":40684892553411,"sku":"OPL-LPRO1","price":179.0,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0596\/1924\/6275\/products\/OptolongL-ProFilter125_2.jpg?v=1631729853"},{"product_id":"optolong-l-pro-deep-sky-light-pollution-filter-2","title":"Optolong L-Pro Deep Sky Light Pollution Filter - 2\"","description":"The L-Pro Filter is the best choice for light pollution suppression and allows astrophotos to be taken of broadband emission objects such as galaxies, reflection nebulae and globular star clusters.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eThe relentless spread or urbanization and its associated light pollution have become a big problem for all amateur astro photographers around the world. One solution is to purchase a Mono camera but this can be expensive and might also require the purchase of several types of narrowband filters and a filter wheel.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eL-Pro is a multi-bandpass filter which offers much better color balance by maximizing the transmission band. The balanced transmission allows astrophotos to be taken with minimal color cast to broadband emission objects such as galaxies, reflection nebulae and globular star clusters. L-Pro remains the best choice for viewing or photographing broadband targets in light polluted areas.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eL-Pro (L-Professional) filter is designed to improve the visibility of various deepsky objects by selectively reducing the transmission of wavelengths of light pollutants, specifically those produced by artificial lights such as 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). Together with the highly transparent main emission lines at OIII (496nm and 500nm), H-beta (486nm), NII (654nm and 658nm), H-alpha (656nm) as well as SII (672nm), the filter is suitable for enhancing the contrast and details for both visual and photograghic purpose at sub-rural areas with heavy light pollution.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eL-Pro has a multiple anti-reflective coating on the optical substrate and uses a precision coating based on ion deposition coating technology. This ensures durability and scratch resistance as well as stability on the CWL (central wavelength), which is not affected by temperature changes.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cem\u003eIMPORTANT WARNING: These nebula filters are NOT designed for observation of the Sun. Do not use this filter to look at the Sun as serious eye damage, blindness as well as damage to equipment may result.\u003c\/em\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cstrong\u003eFeatures:\u003c\/strong\u003e\u003cbr data-mce-fragment=\"1\"\u003e\n\u003cul\u003e\n\u003cli\u003eProfessional visual and photographic filter for astronomy\u003c\/li\u003e\n\u003cli\u003eImproves deep sky nebula constellation photography\u003c\/li\u003e\n\u003cli\u003eBest choice for broadband light pollution suppression\u003c\/li\u003e\n\u003cli\u003eFilter diameter: 2 inch\u003c\/li\u003e\n\u003cli\u003eConnecting thread: M28.5 x 0.6mm (Eyepiece thread 1.25 inch)\u003c\/li\u003e\n\u003cli\u003eSelected optical glass material\u003c\/li\u003e\n\u003cli\u003eSpectrum: 380-750nm\u003c\/li\u003e\n\u003cli\u003eSurface Quality: 60\/40 (Refer to MIL-O-13830)\u003c\/li\u003e\n\u003cli\u003eFine-optically polished glass to ensure accurate 1\/4 wavefront and highest parallelism over the both surfaces\u003c\/li\u003e\n\u003cli\u003eHigh transmission at major nebula emission lines (i.e. H-alpha 656nm, OIII 496nm\u0026amp;500nm, SII 672nm and H-beta 486nm)\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\u003cem\u003eWhats included:\u003c\/em\u003e\u003cbr data-mce-fragment=\"1\"\u003e\n\u003col\u003e\n\u003cli\u003eL-Pro filter (2\")\u003c\/li\u003e\n\u003cli\u003eDust protection box\u003c\/li\u003e\n\u003c\/ol\u003e","brand":"Optolong","offers":[{"title":"Default Title","offer_id":40684948291779,"sku":"0310150","price":229.0,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0596\/1924\/6275\/products\/OptolongL-ProFilter2_2.jpg?v=1631730201"},{"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":385.0,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0596\/1924\/6275\/products\/Optolong-L-Ultimate-Narrowband-Filter.jpg?v=1677184128"},{"product_id":"optolong-l-synergy-dual-narrowband-filter-2","title":"Optolong L-Synergy Dual Narrowband Filter - 2\"","description":"\u003cp\u003eThe core innovation of L-Synergy filters lies not in a single functional breakthrough, but rather in the precise combination of traditional dual-narrowband (Ha \u0026amp; OIII) technology—specifically designed for color Astronomy cameras. By adopting a dual-filter setup of \"Ha \u0026amp; OIII + SII \u0026amp; OIII\", it overcomes the inherent limitations of color cameras in narrowband astrophotography. With L-Synergy, users can achieve Hubble Palette-style deep-sky images comparable to those captured by monochrome SHO (SII\/Ha\/OIII) systems—without switching to a monochrome camera or purchasing additional SHO filters.\u003c\/p\u003e\n\u003cp\u003eThis solution delivers high-quality results with minimal investment, making professional-level narrowband imaging accessible to all.\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003eOptolong L-Synergy is a dual 7nm narrowband filter compatible with DSLR cameras, color CMOS sensors, and CCD cameras, supporting telescope systems with an F-ratio of F3.3 or above (i.e slower systems）. Its key advantage lies in enabling astrophotographers to capture exceptionally detailed emission nebulae even in light-polluted environments.\u003c\/p\u003e\n\u003cp\u003eThe Optolong L-Synergy's advantage lies in its selective transmission of only the nebula emission lines OIII (500.7nm) and SII (672.4nm), while blocking all other light-polluting emission lines. This ensures that only the signals from oxygen and sulfur elements are captured during imaging, resulting in a darker sky background and significantly enhanced contrast and signal-to-noise ratio (SNR) between nebulae.\u003c\/p\u003e\n\u003cp\u003eEven in heavily light-polluted areas, this filter selectively transmits nebula emission lines while filtering out light pollution, ultimately eliminating its impact on astrophotography.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eKey Features:\u003c\/strong\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e2\" low-profile filter holder suitable for filter drawers and filter wheels - with M48x0.75 filter thread.\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eThe filter has a very narrow bandwidth of only 7 nm at O-III and S-II and ensures very high contrast.\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eSuitable for telescopes from F3.3 and slower.\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eAreas of light pollution are completely blocked, making successful deep-sky photography possible even near cities.\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eBest possible anti-reflection coating to prevent halos around stars.\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eThe filter is suitable for mono and color cameras.\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eDelivered in sturdy plastic packaging.\u003cbr\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eSpec:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eFilter size: 2\" mounted\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eMount height: 5mm without external thread, 7mm with M48 thread\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eSubstrate: High-quality optical glass (Schott)\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eSurface: Finely polished\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eFilter type: Dual bandpass filter\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eTransmission ranges: O-III and S-II - 7 nm bandwidth\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eFilter thickness: 2mm\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cem\u003eWhats included:\u003c\/em\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003col\u003e\n\u003cli\u003eOptolong 2\" L-Synergy 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":56206941389135,"sku":"L-Synergy2","price":310.0,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0596\/1924\/6275\/files\/Optolong-Synergy_4.jpg?v=1761112189"}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0596\/1924\/6275\/collections\/Brand_Header_dc23b5bc-1100-421a-a3ff-5bad91df5e81.jpg?v=1779097233","url":"https:\/\/www.horizonastronomy.ie\/en-mt\/collections\/optolong.oembed","provider":"Horizon Astronomy • Telescope Center","version":"1.0","type":"link"}