{"title":"Narrow Band Filters","description":"\u003cp\u003eFor capturing faint emission nebulae or deep-sky targets in light-polluted skies, Optolong narrow-band filters isolate key spectral lines like H-alpha, OIII, and SII to dramatically boost contrast and suppress skyglow. Whether you’re using a monochrome CCD, cooled astro camera, or modified DSLR, these filters help reveal delicate nebular structures that broadband simply misses — making subtle clouds and details pop in your final images. If your goal is maximal clarity and signal-to-noise under challenging skies, narrow-band filters are a foundational part of any serious deep-sky imaging kit.\u003c\/p\u003e","products":[{"product_id":"sho-1-25-narrowband-filter-kit","title":"SHO 1.25\" Narrowband Filter Kit","description":"\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial; font-size: 10pt;\"\u003eSHO in OPTOLONG SHO FILTER KIT stands for SII, H-Alpha, OIII narrow-band filters, generally working with astronomical monochrome cooling CCD and modified DSLR imaging in each single-channel . Corresponding with RGB channel (Ha, OIII, SII), photographers can process Hubble images by astronomical post processing software. The OPTOLONG SHO FILTER KIT contains one H-ALPHA 7NM, one SII 6.5NM and one OIII 6.5NM filter.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eThe OPTOLONG 7NM H-ALPHA FILTER is the most popular narrowband filter allowing 7nm bandwidth of light centered on a wavelength of 656nm.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eThe narrowband OPTOLONG 6.5NM OIII FILTER is designed for nebula observation allowing 6.5nm bandwidth of light centered on a wavelength of 500nm.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial; font-size: 10pt;\"\u003eThe Optolong Sulfur-II 6.5nm Extra-Narrowband Filter transmits a 6.5nm bandwidth of light that is centered at 672nm and drastically reduces other transmissions, including wavelengths of light that are responsible for light pollution (both artificial and natural). \u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Lato, sans-serif; font-size: 10pt;\"\u003eAll of the Optolong Filters  blocks infrared wavelengths from 700nm to 1100nm so you don't need a separate IR-Cut filter.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial;\"\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). Narrowband imaging with SHO set (H-alpha, OIII-CCD and SII-CCD) can be done with the moon up in heavy light pollution, so your equipment is not sitting dormant for several weeks. H-alpha filter is the first narrowband addition to LRGB set for most imagers who blend a black-and-white Ha image into RGB data to enhance structural detail while maintaining natural look.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial;\"\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\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eWARNING: The filters of Optolong are not designed for sun observation. DO NOT LOOK AT THE SUN WITH OPTOLONG FILTER. You would be BLIND if you fail to observe the warning.\u003c\/span\u003e\u003c\/p\u003e","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44013542309999,"sku":"O-SHO-1","price":679.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/125_252520SHO__83393.1682640428.1280.1280.jpg?v=1766555826"},{"product_id":"sho-2-narrowband-filter-kit","title":"SHO 2\" Narrowband Filter Kit","description":"\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial; font-size: 10pt;\"\u003eSHO in OPTOLONG SHO FILTER KIT stands for SII, H-Alpha, OIII narrow-band filters, generally working with astronomical monochrome cooling CCD and modified DSLR imaging in each single-channel . Corresponding with RGB channel (Ha, OIII, SII), photographers can process Hubble images by astronomical post processing software. The OPTOLONG SHO FILTER KIT contains one H-ALPHA 7NM, one SII 6.5NM and one OIII 6.5NM filter.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eThe OPTOLONG 7NM H-ALPHA FILTER is the most popular narrowband filter allowing 7nm bandwidth of light centered on a wavelength of 656nm.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eThe narrowband OPTOLONG 6.5NM OIII FILTER is designed for nebula observation allowing 6.5nm bandwidth of light centered on a wavelength of 500nm.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial; font-size: 10pt;\"\u003eThe Optolong Sulfur-II 6.5nm Extra-Narrowband Filter transmits a 6.5nm bandwidth of light that is centered at 672nm and drastically reduces other transmissions, including wavelengths of light that are responsible for light pollution (both artificial and natural). \u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Lato, sans-serif; font-size: 10pt;\"\u003eAll of the Optolong Filters  blocks infrared wavelengths from 700nm to 1100nm so you don't need a separate IR-Cut filter.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial;\"\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). Narrowband imaging with SHO set (H-alpha, OIII-CCD and SII-CCD) can be done with the moon up in heavy light pollution, so your equipment is not sitting dormant for several weeks. H-alpha filter is the first narrowband addition to LRGB set for most imagers who blend a black-and-white Ha image into RGB data to enhance structural detail while maintaining natural look.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial;\"\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\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eWARNING: The filters of Optolong are not designed for sun observation. DO NOT LOOK AT THE SUN WITH OPTOLONG FILTER. You would be BLIND if you fail to observe the warning.\u003c\/span\u003e\u003c\/p\u003e","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44013542539375,"sku":"O-SHO-2","price":989.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/2_inch_filter_set_with_h-alpha_sii_and_oiii_filteres__16429.jpg?v=1766555832"},{"product_id":"sho-36mm-narrowband-filter-kit","title":"SHO 36mm\" Narrowband Filter Kit","description":"\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial; font-size: 10pt;\"\u003eSHO in OPTOLONG SHO FILTER KIT stands for SII, H-Alpha, OIII narrow-band filters, generally working with astronomical monochrome cooling CCD and modified DSLR imaging in each single-channel . Corresponding with RGB channel (Ha, OIII, SII), photographers can process Hubble images by astronomical post processing software. The OPTOLONG SHO FILTER KIT contains one H-ALPHA 7NM, one SII 6.5NM and one OIII 6.5NM filter.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eThe OPTOLONG 7NM H-ALPHA FILTER is the most popular narrowband filter allowing 7nm bandwidth of light centered on a wavelength of 656nm.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eThe narrowband OPTOLONG 6.5NM OIII FILTER is designed for nebula observation allowing 6.5nm bandwidth of light centered on a wavelength of 500nm.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial; font-size: 10pt;\"\u003eThe Optolong Sulfur-II 6.5nm Extra-Narrowband Filter transmits a 6.5nm bandwidth of light that is centered at 672nm and drastically reduces other transmissions, including wavelengths of light that are responsible for light pollution (both artificial and natural). \u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Lato, sans-serif; font-size: 10pt;\"\u003eAll of the Optolong Filters  blocks infrared wavelengths from 700nm to 1100nm so you don't need a separate IR-Cut filter.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial;\"\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). Narrowband imaging with SHO set (H-alpha, OIII-CCD and SII-CCD) can be done with the moon up in heavy light pollution, so your equipment is not sitting dormant for several weeks. H-alpha filter is the first narrowband addition to LRGB set for most imagers who blend a black-and-white Ha image into RGB data to enhance structural detail while maintaining natural look.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial;\"\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\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 10px; line-height: 1.6em; font-size: 13px; background-color: rgb(255, 255, 255); outline: none 0px !important;\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eWARNING: The filters of Optolong are not designed for sun observation. DO NOT LOOK AT THE SUN WITH OPTOLONG FILTER. You would be BLIND if you fail to observe the warning.\u003c\/span\u003e\u003c\/p\u003e","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44013542637679,"sku":"O-SHO-36","price":809.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/unmounted_filter_set_with_h-alpha_sii_and_oiii_filters__05831.jpg?v=1766555837"},{"product_id":"optolong-sii-6-5nm-2-filter","title":"Optolong SII 6.5nm 2\" filter","description":"\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003e\u003cstrong style=\"box-sizing: border-box;\"\u003eThe SII-CCD 6.5 nm Deep Sky Imaging Filter:\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003eThis filter \u003c\/span\u003eis an e\u003cspan style=\"box-sizing: border-box;\"\u003extra narrowband SII-CCD 6.5 nm filter (Sulfur II for CCD) is designed for nebula observation allowing 6.5 nm bandwidth of light centered on a wavelength of 672 nm 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\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003e\u003cstrong style=\"box-sizing: border-box;\"\u003eMain Use and Performance\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cul style=\"box-sizing: border-box; margin: 4px 0px 5px 30px; list-style-position: outside; list-style-image: initial; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003eUse with H-alpha and OIII-CCD extra narrowband filters (SHO Set) for tricolor CCD astrophotography\u003c\/span\u003e\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\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 style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\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 style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\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","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44013632487535,"sku":"O-SII-2","price":329.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/Optolong-Sulfur-II-Narrowband-Telescope-Filter_2__47046.jpg?v=1766558089"},{"product_id":"optolong-oiii-6-5nm-2-filter","title":"Optolong OIII 6.5nm 2\" Filter","description":"\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003e\u003cstrong style=\"box-sizing: border-box;\"\u003eOIII-CCD 6.5 nm Deep Sky Imaging Filter:\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003e\u003cstrong style=\"box-sizing: border-box;\"\u003e\u003c\/strong\u003e\u003c\/span\u003e\u003cspan style=\"box-sizing: border-box;\"\u003eThis filter is an extra Narrowband OIII-CCD 6.5 nm filter. It is designed for nebula observation allowing 6.5 nm bandwidth of light centered on a wavelength of 500 nm 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. skyglow).\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003eOIII emits 495.9 nm and 500.7 nm and it is a blue-green colored filter. Many of images of planetary nebula and supernova remnants are taken only with H-alpha and OIII filters. They show great structural details, but have natural colors, looking like an RGB image.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003eMain Use and Performance\u003c\/p\u003e\u003cul style=\"box-sizing: border-box; margin: 4px 0px 5px 30px; list-style-position: outside; list-style-image: initial; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003eSuitable for visual observation on most emission nebulae, planetary nebulae and supernova remnants\u003c\/span\u003e\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\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\u003c\/ul\u003e","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44013632520303,"sku":"O-OIII-2","price":329.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/Optolong-Oxygen-III-Narrowband-Telescope-Filter_2000x__61873.jpg?v=1766558094"},{"product_id":"optolong-oiii-6-5nm-1-25-filter","title":"Optolong OIII 6.5nm 1.25\" Filter","description":"\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003e\u003cstrong style=\"box-sizing: border-box;\"\u003eOIII-CCD 6.5 nm Deep Sky Imaging Filter:\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003e\u003cstrong style=\"box-sizing: border-box;\"\u003e\u003c\/strong\u003e\u003c\/span\u003e\u003cspan style=\"box-sizing: border-box;\"\u003eThis filter is an extra Narrowband OIII-CCD 6.5 nm filter. It is designed for nebula observation allowing 6.5 nm bandwidth of light centered on a wavelength of 500 nm 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. skyglow).\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003eOIII emits 495.9 nm and 500.7 nm and it is a blue-green colored filter. Many of images of planetary nebula and supernova remnants are taken only with H-alpha and OIII filters. They show great structural details, but have natural colors, looking like an RGB image.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003eMain Use and Performance\u003c\/p\u003e\u003cul style=\"box-sizing: border-box; margin: 4px 0px 5px 30px; list-style-position: outside; list-style-image: initial; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003eSuitable for visual observation on most emission nebulae, planetary nebulae and supernova remnants\u003c\/span\u003e\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\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\u003c\/ul\u003e","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44013632651375,"sku":"O-OIII-1","price":229.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/Optolong-Oxygen-III-Narrowband-Telescope-Filter_2000x__20500.jpg?v=1766558099"},{"product_id":"optolong-oiii-6-5nm-36mm-filter","title":"Optolong OIII 6.5nm 36mm filter","description":"\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003e\u003cstrong style=\"box-sizing: border-box;\"\u003eOIII-CCD 6.5 nm Deep Sky Imaging Filter:\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003e\u003cstrong style=\"box-sizing: border-box;\"\u003e\u003c\/strong\u003e\u003c\/span\u003e\u003cspan style=\"box-sizing: border-box;\"\u003eThis filter is an extra Narrowband OIII-CCD 6.5 nm filter. It is designed for nebula observation allowing 6.5 nm bandwidth of light centered on a wavelength of 500 nm 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. skyglow).\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003eOIII emits 495.9 nm and 500.7 nm and it is a blue-green colored filter. Many of images of planetary nebula and supernova remnants are taken only with H-alpha and OIII filters. They show great structural details, but have natural colors, looking like an RGB image.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003eMain Use and Performance\u003c\/p\u003e\u003cul style=\"box-sizing: border-box; margin: 4px 0px 5px 30px; list-style-position: outside; list-style-image: initial; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003eSuitable for visual observation on most emission nebulae, planetary nebulae and supernova remnants\u003c\/span\u003e\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\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\u003c\/ul\u003e","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44013634257007,"sku":"O-OIII-36","price":269.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/oiii_36u_2__51982.jpg?v=1766558105"},{"product_id":"optolong-sii-6-5nm-1-25-filter","title":"Optolong SII 6.5nm 1.25\" filter","description":"\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003e\u003cstrong style=\"box-sizing: border-box;\"\u003eThe SII-CCD 6.5 nm Deep Sky Imaging Filter:\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003eThis filter \u003c\/span\u003eis an e\u003cspan style=\"box-sizing: border-box;\"\u003extra narrowband SII-CCD 6.5 nm filter (Sulfur II for CCD) is designed for nebula observation allowing 6.5 nm bandwidth of light centered on a wavelength of 672 nm 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\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003e\u003cstrong style=\"box-sizing: border-box;\"\u003eMain Use and Performance\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cul style=\"box-sizing: border-box; margin: 4px 0px 5px 30px; list-style-position: outside; list-style-image: initial; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003eUse with H-alpha and OIII-CCD extra narrowband filters (SHO Set) for tricolor CCD astrophotography\u003c\/span\u003e\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\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 style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\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 style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\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","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44013634289775,"sku":"O-SII-1","price":229.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/Optolong-Sulfur-II-Narrowband-Telescope-Filter_2__54156.jpg?v=1766558109"},{"product_id":"optolong-sii-6-5nm-36mm-filter","title":"Optolong SII 6.5nm 36mm Filter","description":"\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003e\u003cstrong style=\"box-sizing: border-box;\"\u003eThe SII-CCD 6.5 nm Deep Sky Imaging Filter:\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003eThis filter \u003c\/span\u003eis an e\u003cspan style=\"box-sizing: border-box;\"\u003extra narrowband SII-CCD 6.5 nm filter (Sulfur II for CCD) is designed for nebula observation allowing 6.5 nm bandwidth of light centered on a wavelength of 672 nm 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\u003cp style=\"box-sizing: border-box; margin: 0px 0px 15px; line-height: 1.6em; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003e\u003cstrong style=\"box-sizing: border-box;\"\u003eMain Use and Performance\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cul style=\"box-sizing: border-box; margin: 4px 0px 5px 30px; list-style-position: outside; list-style-image: initial; color: rgb(15, 32, 59); font-family: Poppins, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\u003eUse with H-alpha and OIII-CCD extra narrowband filters (SHO Set) for tricolor CCD astrophotography\u003c\/span\u003e\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\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 style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\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 style=\"box-sizing: border-box; margin-bottom: 6px; width: 870px;\"\u003e\u003cspan style=\"box-sizing: border-box;\"\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","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44013634420847,"sku":"O-SII-36","price":269.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/sii_36u__52005.jpg?v=1766558115"},{"product_id":"optolong-1-25-h-alpha-7nm-filter","title":"OPTOLONG 1.25\" H-ALPHA 7nm FILTER","description":"\u003cul style=\"box-sizing: border-box; margin: 0px 0px 20px 15px; list-style-position: outside; list-style-image: initial; padding: 0px; font-family: Interstate-Light, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 5px;\"\u003eH-alpha 7nm 1.25\" Filter\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 5px;\"\u003eA very narrow emission-line filter\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 5px;\"\u003ePermits a 7nm bandwidth of light (focused on the 656nm wavelength) through\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 0px;\"\u003eBlocks transmission of contrast-killing light pollution wavelengths\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 40px; font-family: Interstate-Light, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e \u003c\/p\u003e","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44013634551919,"sku":"O-HA-1","price":229.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/Optolong_2_H-Alpha_7nm_Filter_grande__97416.jpg?v=1766558121"},{"product_id":"optolong-2-h-alpha-7nm-filter","title":"OPTOLONG 2\" H-ALPHA 7nm FILTER","description":"\u003cul style=\"box-sizing: border-box; margin: 0px 0px 20px 15px; list-style-position: outside; list-style-image: initial; padding: 0px; font-family: Interstate-Light, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 5px;\"\u003eH-alpha 7nm 2\" Filter\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 5px;\"\u003eA very narrow emission-line filter\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 5px;\"\u003ePermits a 7nm bandwidth of light (focused on the 656nm wavelength) through\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 0px;\"\u003eBlocks transmission of contrast-killing light pollution wavelengths\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 40px; font-family: Interstate-Light, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e \u003c\/p\u003e","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44013634584687,"sku":"O-HA-2","price":329.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/Optolong_2_H-Alpha_7nm_Filter_grande__93602.jpg?v=1766558126"},{"product_id":"optolong-36mm-h-alpha-7nm-filter","title":"OPTOLONG 36mm\" H-ALPHA 7nm FILTER","description":"\u003cul style=\"box-sizing: border-box; margin: 0px 0px 20px 15px; list-style-position: outside; list-style-image: initial; padding: 0px; font-family: Interstate-Light, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 5px;\"\u003eH-alpha 7nm 2\" Filter\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 5px;\"\u003eA very narrow emission-line filter\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 5px;\"\u003ePermits a 7nm bandwidth of light (focused on the 656nm wavelength) through\u003c\/li\u003e\n\u003cli style=\"box-sizing: border-box; margin-bottom: 0px;\"\u003eBlocks transmission of contrast-killing light pollution wavelengths\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp style=\"box-sizing: border-box; margin: 0px 0px 40px; font-family: Interstate-Light, sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);\"\u003e \u003c\/p\u003e","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44013634715759,"sku":"O-HA-36","price":269.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/ha_7nm_filter_1__21063.jpg?v=1766558131"},{"product_id":"optolong-sho-3nm-narrowband-filters-kit-36mm","title":"Optolong SHO-3nm narrowband filters kit 36mm","description":"\u003cspan style=\"font-family: \" microsoft yahei rgb font-size:=\"\" background-color:=\"\"\u003eOptolong SHO-3nm filter kit includes SII3nm, H-Alpha3nm, and OIII3nm narrow band filters, generally working with astronomical monochrome cooling CCD and modified DSLR imaging in each single-channel. Corresponding with RGB channel (HA, OIII, SII), photographers can process Hubble images by astronomical post processing software. \u003c\/span\u003e\u003cdiv\u003e\u003cspan style=\"font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e\u003cdiv\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cstrong style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-size: 18px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eOptolong SHO-3nm Narrowband Filters Introduction\u003c\/span\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eOptolong SHO-3nm filter kit includes SII 3nm, H-Alpha 3nm, and OIII 3nm narrow band filters, generally working with astronomical monochrome cooling CCD and modified DSLR imaging in each single-channel. Corresponding with RGB channel (HA, OIII, SII), photographers can process Hubble images by astronomical post processing software. \u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eExtra narrowband SIICCD3nm filter  (Sulfur II for CCD) is designed for nebula observation allowing 3nm 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\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eH-Alpha 3nm filter is the popular narrowband filter allowing 3nm bandwidth of light centered on a wavelength of 656nm 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 vapor lights and unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e.skyglow). Better choice of narrowband H-Alpha astrophotography filter for highest contrast and revealing subtle nebula details. \u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eExtra narrowband OIII-CCD 3nm filter is designed for nebula observation allowing 3nm bandwidth of light centered on a wavelength of 500nm through, which corresponds to OIII emission line, 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\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eOIII emits 495.9nm and 500.7nm and it is a blue-green colored filter. Many of images of planetary nebula and supernoval remnants are taken only with H-Alpha and OIIII filters. They show great structural details, but have natural colors, looking like an RGB image.\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e \u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cstrong style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eFeatures:\u003c\/span\u003e\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eGive you higher contrast and greater detailed viewing;\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eDecrease background noise and improve the contrast of objects;\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eIncrease the faint nebula signal and make it to be brightness;\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eWith narrow band filters kit, you are able to process a Hubble image;\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eThrough the optimization of the substrate and upgrading of coating technology.\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e \u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e \u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e \u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cstrong style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-size: 18px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eReference Spectrum\u003c\/span\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e \u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb text-align: center\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/56095a94c3cebfd0ebdc80f423d27c58_5c02a12e-f3f7-4b80-b5e0-d2f86e183d9a.png?v=1766561315\" style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; border: none; vertical-align: middle; max-width: 100%; height: 462px; width: 1000px;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb text-align: center\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e?This curve is only for reference, and is not used as the final product data.\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e \u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e\u003cstrong style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eHow to read the chart?\u003c\/strong\u003e\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e?The horizontal axis is the Wavelength in Nanometers(nm).\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e?The vertical axis is transmission in %.\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e?The BLUE line shows the transmission of OIII3nm.The H-Alpha 3nm line is shown in GREEN. And the SII 3nm filter line is shown in RED. \u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44013739343983,"sku":"O-SHO-3-36","price":1369.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/Optolong-sho-filter-kit-36-3nm-produkt__29193.jpg?v=1766561317"},{"product_id":"optolong-sho-3nm-narrowband-filters-kit-2","title":"Optolong SHO-3nm narrowband filters kit 2\"","description":"\u003cspan style=\"font-family: \" microsoft yahei rgb font-size:=\"\" background-color:=\"\"\u003eOptolong SHO-3nm filter kit includes SII3nm, H-Alpha3nm, and OIII3nm narrow band filters, generally working with astronomical monochrome cooling CCD and modified DSLR imaging in each single-channel. Corresponding with RGB channel (HA, OIII, SII), photographers can process Hubble images by astronomical post processing software. \u003c\/span\u003e\u003cdiv\u003e\u003cspan style=\"font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e\u003cdiv\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cstrong style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-size: 18px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eOptolong SHO-3nm Narrowband Filters Introduction\u003c\/span\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eOptolong SHO-3nm filter kit includes SII 3nm, H-Alpha 3nm, and OIII 3nm narrow band filters, generally working with astronomical monochrome cooling CCD and modified DSLR imaging in each single-channel. Corresponding with RGB channel (HA, OIII, SII), photographers can process Hubble images by astronomical post processing software. \u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eExtra narrowband SIICCD3nm filter  (Sulfur II for CCD) is designed for nebula observation allowing 3nm 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\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eH-Alpha 3nm filter is the popular narrowband filter allowing 3nm bandwidth of light centered on a wavelength of 656nm 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 vapor lights and unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e.skyglow). Better choice of narrowband H-Alpha astrophotography filter for highest contrast and revealing subtle nebula details. \u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eExtra narrowband OIII-CCD 3nm filter is designed for nebula observation allowing 3nm bandwidth of light centered on a wavelength of 500nm through, which corresponds to OIII emission line, 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\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eOIII emits 495.9nm and 500.7nm and it is a blue-green colored filter. Many of images of planetary nebula and supernoval remnants are taken only with H-Alpha and OIIII filters. They show great structural details, but have natural colors, looking like an RGB image.\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e \u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cstrong style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eFeatures:\u003c\/span\u003e\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eGive you higher contrast and greater detailed viewing;\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eDecrease background noise and improve the contrast of objects;\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eIncrease the faint nebula signal and make it to be brightness;\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eWith narrow band filters kit, you are able to process a Hubble image;\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eThrough the optimization of the substrate and upgrading of coating technology.\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e \u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e \u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e \u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cstrong style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-size: 18px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003eReference Spectrum\u003c\/span\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e \u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb text-align: center\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/56095a94c3cebfd0ebdc80f423d27c58_802f74d5-c34b-498b-ba29-2c995e7f60fd.png?v=1766561323\" style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; border: none; vertical-align: middle; max-width: 100%; height: 462px; width: 1000px;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb text-align: center\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e?This curve is only for reference, and is not used as the final product data.\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e \u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e\u003cstrong style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eHow to read the chart?\u003c\/strong\u003e\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e?The horizontal axis is the Wavelength in Nanometers(nm).\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e?The vertical axis is transmission in %.\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e?The BLUE line shows the transmission of OIII3nm.The H-Alpha 3nm line is shown in GREEN. And the SII 3nm filter line is shown in RED. \u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44013739475055,"sku":"O-SHO-3-2","price":1669.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/SHO_2525203nm__34310.1682640975.1280.1280.png?v=1766561325"},{"product_id":"optolong-ir-pass-685nm-2","title":"Optolong IR Pass 685nm 2\"","description":"\u003cspan style=\"font-family: Arial; font-size: 14px; background-color: rgb(255, 255, 255);\"\u003eIR Pass 685nm filter is designed to block wavelengths below 670nm and can be used in IR-LRGB imaging to produce a sharper luminance image for the best planetary contrast as atmospheric seeing and distortion is much reduced at longer IR wavelengths.\u003c\/span\u003e\u003cdiv\u003e\u003cspan style=\"font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e\u003cdiv\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-size: 18px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e\u003cstrong style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eIR Pass685 Introduction\u003c\/strong\u003e\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-size: 10pt;\"\u003eOptolong IR Pass 685nm filter is designed to block wavelengths below 670nm and can be used in IR-LRGB imaging to produce a sharper luminance image for the best planetary contrast as atmospheric seeing and distortion is much reduced at longer IR wavelengths.\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-size: 10pt;\"\u003eThe sensor of CCD or CMOS cameras is capable of detecting light in the 350-1100nm range including infrared wavelengths. Thus RGB planetary images taken with IR as the luminance channel have visible-enhanced contrast and surface detail than standard LRGB images.\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e \u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-size: 18px;\"\u003e\u003cstrong style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eIR Pass685 Spectrum and Characteristic\u003c\/strong\u003e\u003c\/span\u003e\u003cbr style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eSbustrate: B270\u003cbr style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eThickness: 1.85mm\u003cbr style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eTave:  T\u0026gt;90%\u003cbr style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eBlocking range: 350-1050nm\u003cbr style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eBlcoking depth: light pollution  line blocking \u0026gt;99%\u003cbr style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eSurface quality: 60\/40\u003cbr style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eTransmitted Wavefront RMS: ?\/4\u003cbr style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e Parallelism: 30s\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e \u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb text-align: center\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/f38d04404d461d5c64dd2159dc025330_870265cc-86e5-4418-ac58-9f2f8e31a542.png?v=1766562599\" style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; border: none; vertical-align: middle; max-width: 100%; height: 346px; width: 631px;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44013783056495,"sku":"IR 685-2","price":164.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/O-IR685__59774.jpg?v=1766562601"},{"product_id":"optolong-ir-pass-685nm-1-25","title":"Optolong IR Pass 685nm 1.25\"","description":"\u003cspan style=\"font-family: Arial; font-size: 14px; background-color: rgb(255, 255, 255);\"\u003eIR Pass 685nm filter is designed to block wavelengths below 670nm and can be used in IR-LRGB imaging to produce a sharper luminance image for the best planetary contrast as atmospheric seeing and distortion is much reduced at longer IR wavelengths.\u003c\/span\u003e\u003cdiv\u003e\u003cspan style=\"font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e\u003cdiv\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-size: 18px;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e\u003cstrong style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eIR Pass685 Introduction\u003c\/strong\u003e\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-size: 10pt;\"\u003eOptolong IR Pass 685nm filter is designed to block wavelengths below 670nm and can be used in IR-LRGB imaging to produce a sharper luminance image for the best planetary contrast as atmospheric seeing and distortion is much reduced at longer IR wavelengths.\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-size: 10pt;\"\u003eThe sensor of CCD or CMOS cameras is capable of detecting light in the 350-1100nm range including infrared wavelengths. Thus RGB planetary images taken with IR as the luminance channel have visible-enhanced contrast and surface detail than standard LRGB images.\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e \u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-size: 18px;\"\u003e\u003cstrong style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eIR Pass685 Spectrum and Characteristic\u003c\/strong\u003e\u003c\/span\u003e\u003cbr style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eSbustrate: B270\u003cbr style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eThickness: 1.85mm\u003cbr style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eTave:  T\u0026gt;90%\u003cbr style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eBlocking range: 350-1050nm\u003cbr style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eBlcoking depth: light pollution  line blocking \u0026gt;99%\u003cbr style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eSurface quality: 60\/40\u003cbr style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003eTransmitted Wavefront RMS: 1\/4\u003cbr style=\"overflow-wrap: break-word; margin: 0px; padding: 0px;\"\u003e Parallelism: 30s\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb\u003e \u003c\/p\u003e\n\u003cp style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: \" microsoft yahei font-size: background-color: rgb text-align: center\u003e\u003cspan style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; font-family: Arial, Helvetica, sans-serif;\"\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/f38d04404d461d5c64dd2159dc025330_0c1ef099-a786-47d0-bc0e-8c33b2ad0042.png?v=1766562607\" style=\"overflow-wrap: break-word; margin: 0px; padding: 0px; border: none; vertical-align: middle; max-width: 100%; height: 346px; width: 631px;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44013783187567,"sku":"IR 685-1","price":109.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/O-IR685__87378.jpg?v=1766562609"},{"product_id":"optolong-night-sky-h-alpha-filter","title":"Optolong Night Sky H-Alpha filter","description":"\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eOptolong Night Sky H-Alpha Introduction\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eNight Sky H-Alpha filter (IR Pass 650nm) with 50% transition from blocking to passing at about 640nm and 95% or above transmission at wavelengths longer than 650nm can be used in IR-LRGB imaging to produce a sharper luminance image for the best planetary contrast as atmospheric seeing and distortion is much reduced at longer IR wavelengths.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eMain Use\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe sensor of CCD or CMOS cameras is capable of detecting light in the 350-1100nm range including infrared wavelengths. Thus RGB planetary images taken with IR as the luminance channel have visible-enhanced contrast and surface detail than standard LRGB images.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eWARNING: The filters of Optolong are not designed for sun observation. DO NOT LOOK AT THE SUN WITH OPTOLONG FILTER. You would be BLIND if you fail to observe the warning.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eOptolong \u003c\/strong\u003e\u003c\/span\u003e\u003cspan\u003e\u003cstrong\u003eNight Sky H-Alpha\u003c\/strong\u003e\u003c\/span\u003e\u003cspan\u003e\u003cstrong\u003e Spectrum and Characteristic\u003c\/strong\u003e\u003cbr\u003eSbustrate: Optical glass\u003cbr\u003eThickness: 1.85mm\u003cbr\u003eTave:  T\u0026gt;90%\u003cbr\u003eBlocking range: 300-570nm\u003cbr\u003eSurface quality: 60\/40\u003cbr\u003eTransmitted Wavefront RMS: λ\/4\u003cbr\u003eParallelism: 30s\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/afe8c3f4e4eb968ef68dd5839b667b29_1a9b17f8-620a-4047-be2d-e6f582975e46.png?v=1766572968\" alt=\"\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eHow to read the chart?\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe horizontal axis is the Wavelength in Nanometers(nm).\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe vertical axis is transmission in %.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe \u003cstrong\u003eRED\u003c\/strong\u003e line shows the transmission of the \u003c\/span\u003e\u003cspan\u003e\u003cstrong\u003eNight Sky H-Alpha\u003c\/strong\u003e\u003c\/span\u003e\u003cspan\u003e filter.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eCoating Technology\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e·Multi-layers anti-reflection coating\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e·Non-cementing optical substrate coating\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e·Optolong filter adopts precision coating based on 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\/p\u003e\n\u003cp\u003e\u003cspan\u003e·Planetary 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\/p\u003e","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44014146781295,"sku":"O-Ha-NS-1","price":110.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/3d46da1c9e20c7176d9f19420034d9b3__40980.jpg?v=1766572970"},{"product_id":"optolong-night-sky-h-alpha-filter-2","title":"Optolong Night Sky H-Alpha filter 2\"","description":"\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eOptolong Night Sky H-Alpha Introduction\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eNight Sky H-Alpha filter (IR Pass 650nm) with 50% transition from blocking to passing at about 640nm and 95% or above transmission at wavelengths longer than 650nm can be used in IR-LRGB imaging to produce a sharper luminance image for the best planetary contrast as atmospheric seeing and distortion is much reduced at longer IR wavelengths.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eMain Use\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe sensor of CCD or CMOS cameras is capable of detecting light in the 350-1100nm range including infrared wavelengths. Thus RGB planetary images taken with IR as the luminance channel have visible-enhanced contrast and surface detail than standard LRGB images.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eWARNING: The filters of Optolong are not designed for sun observation. DO NOT LOOK AT THE SUN WITH OPTOLONG FILTER. You would be BLIND if you fail to observe the warning.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eOptolong \u003c\/strong\u003e\u003c\/span\u003e\u003cspan\u003e\u003cstrong\u003eNight Sky H-Alpha\u003c\/strong\u003e\u003c\/span\u003e\u003cspan\u003e\u003cstrong\u003e Spectrum and Characteristic\u003c\/strong\u003e\u003cbr\u003eSbustrate: Optical glass\u003cbr\u003eThickness: 1.85mm\u003cbr\u003eTave:  T\u0026gt;90%\u003cbr\u003eBlocking range: 300-570nm\u003cbr\u003eSurface quality: 60\/40\u003cbr\u003eTransmitted Wavefront RMS: λ\/4\u003cbr\u003eParallelism: 30s\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/afe8c3f4e4eb968ef68dd5839b667b29_4da6abeb-6d7e-4490-93a7-886226364cad.png?v=1766572977\" alt=\"\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eHow to read the chart?\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe horizontal axis is the Wavelength in Nanometers(nm).\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe vertical axis is transmission in %.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe \u003cstrong\u003eRED\u003c\/strong\u003e line shows the transmission of the \u003c\/span\u003e\u003cspan\u003e\u003cstrong\u003eNight Sky H-Alpha\u003c\/strong\u003e\u003c\/span\u003e\u003cspan\u003e filter.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eCoating Technology\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e·Multi-layers anti-reflection coating\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e·Non-cementing optical substrate coating\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e·Optolong filter adopts precision coating based on 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\/p\u003e\n\u003cp\u003e\u003cspan\u003e·Planetary 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\/p\u003e","brand":"Optolong Filters","offers":[{"title":"Default Title","offer_id":44014147141743,"sku":"O-Ha-NS-2","price":165.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/3d46da1c9e20c7176d9f19420034d9b3__40980.1763489464.1280.1280__31623.jpg?v=1766572979"},{"product_id":"explore-scientific-1-25-inch-sulphur-ii-12nm-nebula-filter","title":"Explore Scientific 1.25-inch Sulphur II 12nm Narrowband Nebula Filter","description":"\u003ch2\u003eProduct Overview\u003c\/h2\u003e\u003cp\u003eThe Explore Scientific 1.25-inch S-II Nebula Filter is a narrowband interference filter with a 12 nm passband centred on the ionised sulphur emission line at 672 nm. Explore Scientific states the design goal plainly: block the rest of the spectrum, and with it almost all artificial light, so that only the sulphur emission from the nebula reaches your eyepiece or sensor. It is supplied in a standard 1.25-inch threaded cell, and like every filter in this Explore Scientific narrowband range it arrives with an individual test report for the specific piece of glass in the cell.\u003c\/p\u003e\u003ch2\u003eWho It's For\u003c\/h2\u003e\u003cp\u003eS-II is the difficult member of the usual narrowband trio. In most emission nebulae the ionised sulphur signal is considerably weaker than hydrogen-alpha, and it is frequently weaker than doubly ionised oxygen as well. That changes how you should think about bandpass. Going narrower always buys contrast, because the sky background falls roughly in proportion to the width of the passband while the emission line itself passes through intact. It also costs you, though: a narrower filter is less tolerant of a converging light cone, less tolerant of focus and temperature drift, and it makes an already faint subject fainter on the chip. With S-II you are starting from a weak signal, so 12 nm is the sensible default rather than a compromise.\u003c\/p\u003e\u003cp\u003eThis is the filter to reach for if you are assembling your first mapped-colour narrowband set, if you image at f\/4 to f\/6 where a very narrow band begins to shift and lose effective transmission across the field, or if you are working with a 200 mm or smaller aperture and cannot realistically commit twenty-minute subframes to the weakest channel of a three-channel project. It suits 1.25-inch filter wheels and sensors up to roughly Four Thirds or small APS-C format. If your rig is fast and modest in aperture, the extra photons the 12 nm passband lets through will do more for your final image than the extra sky rejection of a 6.5 nm filter would.\u003c\/p\u003e\u003ch2\u003eKey Features \u0026amp; Design\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e12 nm passband, wide enough to keep the weak S-II signal usable on modest apertures and fast optics\u003c\/li\u003e\n\u003cli\u003eCentred on the ionised sulphur emission line at 672 nm, deep in the red\u003c\/li\u003e\n\u003cli\u003eInterference coatings reject the rest of the visible spectrum, including the mercury and sodium vapour lines that dominate urban skyglow\u003c\/li\u003e\n\u003cli\u003eStandard 1.25-inch threaded cell that fits eyepiece barrels, camera nosepieces and 1.25-inch filter wheels\u003c\/li\u003e\n\u003cli\u003eIndividual test report for your specific filter included in the scope of delivery\u003c\/li\u003e\n\u003cli\u003eBuilt for the sulphur channel of narrowband imaging, with useful contrast on bright planetary nebulae in larger visual apertures\u003c\/li\u003e\n\u003cli\u003eExplore Scientific positions the S-II filter specifically at urban observers and astrophotographers fighting a brightened sky\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eFilter Design\u003c\/h2\u003e\u003cp\u003eAn interference filter of this kind works through thin-film physics rather than absorption. Many alternating layers of high and low refractive index material are deposited on the substrate, and light at the design wavelength reflects between those layers in phase and is transmitted, while everything else interferes destructively and is rejected. The consequence worth understanding is that the passband is defined for light arriving perpendicular to the coating. As the angle of incidence rises, the effective optical thickness of each layer falls and the whole passband shifts toward the blue. In the converging beam of a fast telescope the edge rays arrive at a meaningful angle, so part of your light cone sees a passband that no longer sits on 672 nm. A 12 nm window has enough margin to absorb that shift at ordinary imaging speeds, which is exactly why it remains a practical choice for f\/4 and f\/5 systems where a much narrower filter would start to lose transmission toward the edge of the field.\u003c\/p\u003e\u003ch2\u003eRecommended Uses\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eThe sulphur channel of mapped-colour narrowband imaging on emission nebulae\u003c\/li\u003e\n\u003cli\u003eSupernova remnants such as the Veil, where S-II structure is genuinely distinct from hydrogen\u003c\/li\u003e\n\u003cli\u003ePlanetary nebulae, where sulphur often traces the outer shells\u003c\/li\u003e\n\u003cli\u003eImaging from suburban and urban sites, or under moonlight, when broadband work is not an option\u003c\/li\u003e\n\u003cli\u003eContrast work on bright planetary nebulae visually, with generous aperture\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCompatibility and Accessory Notes\u003c\/h2\u003e\u003cp\u003eThe cell uses the standard 1.25-inch filter thread, so it screws into the bottom of a conventional 1.25-inch eyepiece barrel, into a 1.25-inch camera nosepiece, or into the carousel of a 1.25-inch filter wheel. It will not fit a 2-inch wheel or an unmounted 31 mm or 36 mm filter drawer without an adapter, and mounted 1.25-inch filters are too thick for many slim internal drawers. If you are building a full narrowband set, keep it within the same Explore Scientific 1.25-inch family so that your exposure planning stays consistent from channel to channel. If you are unsure whether your particular filter wheel, off-axis guider or backfocus budget will take a mounted 1.25-inch filter, contact our team in Bolton and we will confirm the fit before you order.\u003c\/p\u003e\u003ch2\u003eGood to Know Before You Order\u003c\/h2\u003e\u003cp\u003eExplore Scientific publishes no shipping weight for this item, so we are confirming it on our own scales before the listing goes live. That is why it is currently unpublished. Contact us and we will give you a shipping figure for your address. Beyond that, be realistic about visual use: at 672 nm the dark-adapted eye is already well down its sensitivity curve, and on all but the brightest planetary nebulae in a large aperture this behaves as a photographic filter. Explore Scientific does not publish a peak transmission figure, a substrate specification or a full blocking range for this filter, so we will not quote numbers we cannot source; the individual test report in the box gives the measured curve for the filter you receive. Explore Scientific lists the filter and that test report as the scope of delivery, so no eyepiece, nosepiece, filter wheel or adapter is included.\u003c\/p\u003e\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eWill I see anything through this filter visually?\u003c\/strong\u003e On a large aperture and a bright planetary nebula, sometimes. In general, no. S-II sits deep in the red where the dark-adapted eye is least sensitive, and a 12 nm window passes very little total light. Treat it as an imaging filter and use an O-III or broadband nebula filter for visual work.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy choose 12 nm rather than the 6.5 nm version?\u003c\/strong\u003e Because sulphur is faint. The narrower filter darkens the sky background further, but it also demands longer subframes, more aperture and a slower light cone to hold its passband. If you image at f\/4 to f\/6, or your total integration per target is a few hours rather than tens of hours, the 12 nm filter will usually give you the cleaner sulphur channel.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it work with a one-shot colour camera or a DSLR?\u003c\/strong\u003e It will pass light, but only the red-sensitive photosites contribute, so most of your sensor sits idle and the Bayer array costs you further transmission. Narrowband filters of this kind are built around monochrome cameras.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much sensor will it cover?\u003c\/strong\u003e A mounted 1.25-inch filter typically offers a clear aperture near 27 mm, which comfortably covers Four Thirds and smaller sensors. On APS-C and larger, expect vignetting and step up to the 2-inch version.\u003c\/p\u003e\u003ch2\u003eBottom Line\u003c\/h2\u003e\u003cp\u003eThe 12 nm S-II is the version of this filter that keeps the weakest narrowband channel practical for ordinary apertures, ordinary exposure budgets and fast optics. If you are building a 1.25-inch narrowband set and want sulphur data you can actually stretch, this is the sensible place to start. Contact us and we will help you match it to your camera, wheel and focal ratio.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":53958583418991,"sku":"310115","price":179.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/310115_2.jpg?v=1785960578"},{"product_id":"explore-scientific-1-25-inch-sulphur-ii-6-5nm-nebula-filter","title":"Explore Scientific 1.25-inch Sulphur II 6.5nm Narrowband Nebula Filter","description":"\u003ch2\u003eProduct Overview\u003c\/h2\u003e\u003cp\u003eThis is the tighter of the two 1.25-inch sulphur filters Explore Scientific builds: a narrowband interference filter with a 6.5 nm passband sitting on the ionised sulphur emission line at 672 nm. Explore Scientific describes the effect in blunt terms, noting that with the filter in place fog becomes visible in places that appear completely empty without one. The filter comes in a standard 1.25-inch threaded cell and is supplied with an individual test report measured on the actual filter you receive rather than a generic curve for the product line.\u003c\/p\u003e\u003ch2\u003eWho It's For\u003c\/h2\u003e\u003cp\u003eHalving the passband does something specific and worth being precise about. The emission line you want is a few tenths of a nanometre wide, so narrowing the window from 12 nm to 6.5 nm passes essentially the same nebular signal while cutting the continuum sky background you collect alongside it by close to half. In a background-limited exposure that is a real gain in signal-to-noise, and it is why this filter keeps working on nights when a 12 nm filter is already struggling: near a gibbous or full moon, under a bright suburban dome, or on targets low enough to sit in the worst of the light dome.\u003c\/p\u003e\u003cp\u003eThe bill comes due elsewhere. Sulphur is the faintest of the three lines normally mapped in narrowband work, and a tighter filter is more sensitive to the angle at which light strikes it. That combination means this filter wants a slower light cone, roughly f\/5 and above, a camera with low read noise so that long subframes are not wasted, and an owner willing to spend real integration time on the sulphur channel: ten to twenty minute subframes and several hours per session are normal here, not exceptional. Choose it if you already know your way around narrowband processing, if your sky is genuinely bright and you need the extra rejection more than the extra photons, or if you image with enough aperture that the faintness of S-II is not the limiting factor. If you are still on a fast small refractor and short exposures, the 12 nm sibling is the better tool.\u003c\/p\u003e\u003ch2\u003eKey Features \u0026amp; Design\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e6.5 nm passband, roughly half the sky background of a 12 nm filter for the same nebular signal\u003c\/li\u003e\n\u003cli\u003eCentred on the ionised sulphur emission line at 672 nm\u003c\/li\u003e\n\u003cli\u003eDeep rejection of the rest of the visible spectrum, including mercury and sodium vapour street lighting\u003c\/li\u003e\n\u003cli\u003eMounted in a standard 1.25-inch threaded cell for eyepiece barrels, nosepieces and 1.25-inch filter wheels\u003c\/li\u003e\n\u003cli\u003eIndividual test report for the specific filter supplied, included with the product\u003c\/li\u003e\n\u003cli\u003eSuited to planetary nebulae, emission nebulae and supernova remnants, the three families Explore Scientific names for this filter\u003c\/li\u003e\n\u003cli\u003eHolds contrast in moonlight where wider narrowband filters begin to lose it\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eFilter Design\u003c\/h2\u003e\u003cp\u003eThe passband of a dielectric interference filter is set by the optical thickness of its coating layers, and that optical thickness depends on the path a ray takes through them. Light arriving square to the surface sees the design thickness; light arriving at an angle sees a different one, and the whole transmission curve slides toward shorter wavelengths. The shift is not large in absolute terms, but it is measured against the width of your window. A ray tilted enough to move the band by two nanometres is a minor nuisance in a 12 nm filter and a significant loss of transmission in a 6.5 nm one, because the 672 nm line you are trying to record is now sitting on the shoulder of the curve rather than at its peak. This is the physical reason narrower filters are usually specified with a focal ratio limit, and why 6.5 nm is best matched to systems around f\/5 and slower rather than to fast astrographs.\u003c\/p\u003e\u003ch2\u003eRecommended Uses\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eSulphur data for mapped-colour narrowband imaging from bright suburban and urban sites\u003c\/li\u003e\n\u003cli\u003eImaging through moonlight, when the sky background rather than the target sets your limit\u003c\/li\u003e\n\u003cli\u003eSupernova remnants and planetary nebulae where sulphur structure is the point of the exercise\u003c\/li\u003e\n\u003cli\u003eLong-integration projects on emission nebulae where the sulphur channel needs the most help\u003c\/li\u003e\n\u003cli\u003eMonochrome cameras on 1.25-inch filter wheels with sensors up to about Four Thirds format\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCompatibility and Accessory Notes\u003c\/h2\u003e\u003cp\u003eStandard 1.25-inch filter threads mean this screws directly into a 1.25-inch camera nosepiece, an eyepiece barrel, or the carousel of a 1.25-inch filter wheel. It is not a match for 2-inch wheels or for the unmounted 31 mm and 36 mm formats used in many larger wheels, and the extra thickness of a mounted cell can matter in tight backfocus arrangements with an off-axis guider. If you already own the matching Explore Scientific hydrogen-alpha filter at a different bandwidth, be aware that mixing widths across a set means each channel reaches a given depth at a different rate, which complicates exposure planning more than it complicates processing. Send us your imaging train and our team in Bolton will confirm the fit and the spacing before you order.\u003c\/p\u003e\u003ch2\u003eGood to Know Before You Order\u003c\/h2\u003e\u003cp\u003eExplore Scientific publishes no shipping weight for this item, so we are confirming it on our own scales before the listing goes live. That is why it is currently unpublished. Contact us and we will give you a shipping figure for your address. Two other things are worth saying plainly. First, this is not a visual filter in any practical sense: 6.5 nm at 672 nm leaves far too little light for the dark-adapted eye. Second, Explore Scientific does not publish peak transmission, substrate or out-of-band blocking figures on the product page, so we do not repeat numbers we cannot verify. The individual test report packed with the filter is the authoritative measurement for your copy. The scope of delivery is the filter and that report; camera, wheel, adapters and spacers are not included.\u003c\/p\u003e\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eIs 6.5 nm always better than 12 nm?\u003c\/strong\u003e No. It is better when the sky background is what limits you, which is most urban and moonlit nights. It is worse when the target itself is what limits you, which is what happens on a fast small aperture with short subframes on a faint line like sulphur. Match the filter to your bottleneck.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat focal ratio can I use it at?\u003c\/strong\u003e Explore Scientific does not publish a limit, but the physics of interference coatings means that below roughly f\/4 the passband shift across a converging beam starts to cost you real transmission at 672 nm. Around f\/5 and slower this filter is comfortable. If you are near the boundary, contact us and we will talk through your specific optics.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow long should my subframes be?\u003c\/strong\u003e Longer than you are used to. With a cooled monochrome camera, ten to twenty minutes per subframe on the sulphur channel is a reasonable starting point, and expect to need more total integration on S-II than on hydrogen-alpha for the same target.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the test report matter?\u003c\/strong\u003e It is genuinely useful. It tells you where the centre wavelength of your particular filter landed and how the transmission curve is shaped, which is the information you need if you are ever troubleshooting a weak channel.\u003c\/p\u003e\u003ch2\u003eBottom Line\u003c\/h2\u003e\u003cp\u003eThe 6.5 nm S-II is the version for imagers whose enemy is the sky, not the clock: it trades photons for contrast and rewards patience, aperture and a moderate focal ratio. If you are already producing usable sulphur data and want it cleaner under a brighter sky, this is the upgrade. Contact us if you would like a second opinion on whether your rig will make the most of it.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":53958658752623,"sku":"310125","price":193.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/310125_2.jpg?v=1785960770"},{"product_id":"explore-scientific-1-25-inch-h-alpha-12nm-nebula-filter","title":"Explore Scientific 1.25-inch Hydrogen-Alpha 12nm Narrowband Nebula Filter","description":"\u003ch2\u003eProduct Overview\u003c\/h2\u003e\u003cp\u003eThe Explore Scientific 1.25-inch H-Alpha Nebula Filter has a 12 nm passband and is built to pass the hydrogen emission line at 656.3 nm while rejecting everything else. Explore Scientific is direct about the intended use: this is a filter developed for astrophotography, aimed squarely at imagers working near cities, and the company notes it blocks almost all the light from mercury and sodium vapour lamps. It comes mounted in a standard 1.25-inch threaded cell with an individual test report for the filter in the box.\u003c\/p\u003e\u003ch2\u003eWho It's For\u003c\/h2\u003e\u003cp\u003eHydrogen-alpha is the loud one. In an emission nebula it is normally the strongest of the three lines narrowband imagers work with, often by a wide margin, and that single fact changes the whole calculation around bandpass. Because the signal is strong, you do not need to squeeze the window down to get a usable result, and a 12 nm passband gives you something more valuable on modest equipment: tolerance. Tolerance of a fast light cone, where the passband shifts as rays strike the coating off-axis. Tolerance of shorter subframes, because the target is bright enough that you are not waiting forever to climb out of the read noise. Tolerance of nights that are less than ideal, since the streetlight emission that ruins broadband work sits at 589 nm and below, comfortably outside this window.\u003c\/p\u003e\u003cp\u003eThat makes this the natural first narrowband filter for someone with a 1.25-inch filter wheel and a small monochrome sensor, for an f\/4 or f\/5 Newtonian where a 3 nm filter would be a poor match, or for anyone who wants a hydrogen luminance layer to blend into an existing colour image. It is also the honest choice if your total time per target is one or two nights rather than one or two months. If you routinely image from a genuinely bright site through a full moon and you already own a slower scope and a patient temperament, the tighter 7 nm hydrogen-alpha filters will pull the background down further; for everyone else, 12 nm is the width that gets a good image out of ordinary conditions.\u003c\/p\u003e\u003ch2\u003eKey Features \u0026amp; Design\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e12 nm passband on the hydrogen emission line at 656.3 nm, in the red\u003c\/li\u003e\n\u003cli\u003eExplore Scientific states it blocks almost all light from mercury and sodium vapour street lighting\u003c\/li\u003e\n\u003cli\u003eWide enough to stay well behaved in fast light cones around f\/4 to f\/5\u003c\/li\u003e\n\u003cli\u003eStandard 1.25-inch threaded cell for nosepieces, eyepiece barrels and 1.25-inch filter wheels\u003c\/li\u003e\n\u003cli\u003eIndividual test report for the specific filter included with the product\u003c\/li\u003e\n\u003cli\u003eExplore Scientific specifies it for astrophotography rather than visual observing\u003c\/li\u003e\n\u003cli\u003eRecords red emission nebulae to their full extent in photographs where an unfiltered exposure shows mostly skyglow\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eFilter Design\u003c\/h2\u003e\u003cp\u003eA narrowband filter is not tinted glass. It is a stack of dielectric layers whose thicknesses are chosen so that light near 656 nm reflects back and forth between them in phase and emerges, while every other wavelength interferes with itself and is turned back. The reason this matters for a 12 nm filter specifically is that the window's width is what buys you angular tolerance. The transmission curve moves toward the blue as the angle of incidence increases, and in a converging beam the edge of your light cone is always arriving at an angle. With 12 nm of width the shift produced by an f\/4 or f\/5 cone still leaves 656.3 nm sitting near the top of the curve across the whole field, so the centre and the corners of the frame record the same signal. Narrow that window enough and the corners start to see a filter that is no longer tuned to hydrogen, which shows up as an unevenly illuminated frame that no amount of flat-fielding fixes properly.\u003c\/p\u003e\u003ch2\u003eRecommended Uses\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eThe hydrogen channel of mapped-colour narrowband imaging on emission nebulae\u003c\/li\u003e\n\u003cli\u003eHydrogen-alpha luminance layers blended into broadband colour images\u003c\/li\u003e\n\u003cli\u003eImaging emission nebulae and supernova remnants from urban and suburban back gardens\u003c\/li\u003e\n\u003cli\u003eContinuing to collect useful data through moonlight, when broadband imaging is finished for the night\u003c\/li\u003e\n\u003cli\u003eFast Newtonians and small refractors at f\/4 to f\/6 with monochrome cameras\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCompatibility and Accessory Notes\u003c\/h2\u003e\u003cp\u003eThe cell carries the usual 1.25-inch filter thread, so it will thread into a 1.25-inch camera nosepiece, the barrel of a 1.25-inch eyepiece, or a 1.25-inch filter wheel carousel. It is not intended for 2-inch focusers or for wheels built around unmounted 31 mm and 36 mm discs. If your imaging train is tight on backfocus, remember that a mounted filter adds a few millimetres of glass in the optical path and shifts focus slightly rearward, which is worth accounting for when you set your spacing to a field flattener. This is also the filter most people pair first with a matching Explore Scientific O-III and S-II in the same 1.25-inch format when they are building a full narrowband set. Tell us what camera and wheel you are running and our team in Bolton will confirm the fit.\u003c\/p\u003e\u003ch2\u003eGood to Know Before You Order\u003c\/h2\u003e\u003cp\u003eExplore Scientific publishes no shipping weight for this item, so we are confirming it on our own scales before the listing goes live. That is why it is currently unpublished. Contact us and we will give you a shipping figure for your address. It is also worth repeating that Explore Scientific specifies this filter for photographic use. Visually, a 12 nm window in the deep red passes far too little light for the dark-adapted eye to do much with, and you should not buy this expecting an eyepiece filter. Explore Scientific does not publish peak transmission, substrate or blocking specifications for the filter, so we do not quote figures we cannot source; the enclosed test report is the measurement that applies to your copy. The scope of delivery is the filter and its report, with no adapters, wheel or camera included.\u003c\/p\u003e\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eCan I use this with an unmodified DSLR?\u003c\/strong\u003e You can, but the result will disappoint you. The internal cut filter in a stock camera is designed to attenuate exactly the deep red region where hydrogen-alpha sits, so you lose most of the signal before it reaches the sensor. A modified or astronomy-specific camera is the right partner for this filter, and a monochrome camera is better still.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy start with hydrogen-alpha rather than O-III or S-II?\u003c\/strong\u003e Because it is the strongest line and the most forgiving. You will get a usable image from a single night with H-alpha long before you get one with sulphur, and the technique you learn on this filter transfers directly to the others.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs 12 nm too wide for a light-polluted sky?\u003c\/strong\u003e Not for hydrogen. The window at 656 nm sits clear of the sodium and mercury emission that dominates urban skyglow, so a 12 nm filter already removes the great majority of what a broadband exposure suffers from. A tighter filter reduces the remaining continuum background further, which matters most under a bright moon.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill it vignette on my sensor?\u003c\/strong\u003e A mounted 1.25-inch filter usually offers a clear aperture near 27 mm, which is comfortable for Four Thirds and smaller chips. Larger sensors want the 2-inch version of this filter.\u003c\/p\u003e\u003ch2\u003eBottom Line\u003c\/h2\u003e\u003cp\u003eIf you are taking your first serious step into narrowband imaging with a 1.25-inch wheel and a small sensor, the 12 nm hydrogen-alpha is the filter that gives you the most result for the least demanded of your equipment. It is forgiving of fast optics, short subframes and imperfect nights in a way the tighter filters are not. Contact us and we will help you slot it into your imaging train.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":53958684409967,"sku":"310135","price":154.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/310135_2.jpg?v=1785960832"},{"product_id":"explore-scientific-2-inch-sulphur-ii-12nm-nebula-filter","title":"Explore Scientific 2-inch Sulphur II 12nm Narrowband Nebula Filter","description":"\u003ch2\u003eProduct Overview\u003c\/h2\u003e\u003cp\u003eThe Explore Scientific 2-inch S-II Nebula Filter is a 12 nm narrowband filter tuned to the ionised sulphur emission line at 672 nm, mounted in a 2-inch cell. Explore Scientific explains the principle behind it directly: emission nebulae glow in specific colours tied to specific chemical elements, and this filter blocks all the other colours, and with them almost all artificial light, letting only the sulphur emission through. Each filter ships with an individual test report for that particular piece of glass.\u003c\/p\u003e\u003ch2\u003eWho It's For\u003c\/h2\u003e\u003cp\u003eThe reason to buy this rather than the 1.25-inch version is aperture, and the reason to buy 12 nm rather than 6.5 nm is what a large aperture does to a narrowband filter. On a big sensor the light reaching one corner of the frame arrives at the filter with a different angle and a different range of angles than the light landing at the centre. Because an interference coating shifts its passband toward the blue as the angle of incidence increases, that means the corners of a full-frame chip are effectively looking through a slightly different filter than the middle. With a 12 nm window there is enough room either side of 672 nm to absorb that variation, and your corners and your centre record the sulphur line at comparable efficiency. Tighten the window and the difference starts to appear in the data as a radial falloff that is not a vignette and does not calibrate out cleanly.\u003c\/p\u003e\u003cp\u003eSo this is the sulphur filter for someone running a full-frame or large APS-C monochrome camera in a 2-inch filter wheel or drawer, or for an observer with a large-aperture visual instrument who wants to try sulphur contrast on bright planetary nebulae through a 2-inch diagonal. It also suits fast, wide astrographs where both the focal ratio and the field size are working against a narrow band at once. Given that sulphur is already the faintest of the commonly mapped lines, the extra photons a 12 nm window collects are worth more here than the additional background suppression a 6.5 nm filter would provide, unless your sky is exceptionally bright.\u003c\/p\u003e\u003ch2\u003eKey Features \u0026amp; Design\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e2-inch mounted cell, sized for full-frame sensors, 2-inch filter wheels and 2-inch diagonals\u003c\/li\u003e\n\u003cli\u003e12 nm passband centred on the ionised sulphur emission line at 672 nm\u003c\/li\u003e\n\u003cli\u003eRejects the remainder of the visible spectrum, including the artificial light that dominates an urban sky\u003c\/li\u003e\n\u003cli\u003eBandwidth chosen to stay consistent from field centre to corner across a large sensor\u003c\/li\u003e\n\u003cli\u003eIndividual test report for the filter you receive, included in the scope of delivery\u003c\/li\u003e\n\u003cli\u003eExplore Scientific names planetary nebulae, emission nebulae and supernova remnants as its targets\u003c\/li\u003e\n\u003cli\u003eUsable both photographically and, on large apertures, for visual contrast work on the brightest planetaries\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eFilter Design\u003c\/h2\u003e\u003cp\u003eThe 672 nm passband is produced by a multilayer dielectric coating, and its behaviour depends on geometry as much as on chemistry. Each layer is a fraction of a wavelength thick, and the interference condition that defines the transmission peak depends on the optical path a ray takes through the stack. Rays arriving perpendicular to the surface see the design condition. Rays arriving at an angle satisfy the same condition at a shorter wavelength, so the peak migrates blueward. In a 2-inch filter placed in a converging beam ahead of a large sensor, the angle of incidence varies systematically across the aperture of the filter, which is why the 12 nm width is the practical choice at this size: it is broad enough that the whole illuminated area of the coating still delivers the sulphur line near peak transmission. A wider window does admit slightly more sky continuum, but with a line as faint as S-II, uniform transmission across the field is usually the more valuable property.\u003c\/p\u003e\u003ch2\u003eRecommended Uses\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eSulphur data for mapped-colour narrowband imaging on full-frame and large APS-C monochrome cameras\u003c\/li\u003e\n\u003cli\u003eWide-field emission nebula work with fast astrographs and short focal lengths\u003c\/li\u003e\n\u003cli\u003eSupernova remnants where the sulphur structure diverges from the hydrogen structure\u003c\/li\u003e\n\u003cli\u003eImaging from suburban and urban sites where broadband work is not practical\u003c\/li\u003e\n\u003cli\u003eVisual contrast work on bright planetary nebulae through a 2-inch diagonal with generous aperture\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCompatibility and Accessory Notes\u003c\/h2\u003e\u003cp\u003eThe cell is threaded to the standard 2-inch filter thread, so it screws into the barrel of a 2-inch eyepiece, into a 2-inch nosepiece or star diagonal, and into most 2-inch filter wheels. It does not fit wheels that take unmounted 36 mm or 50.8 mm discs, and its cell thickness is worth checking against tight filter drawers before you commit. If you already own the 1.25-inch Explore Scientific narrowband filters, note that a 2-inch cell will not step down without an adapter, and that the mounted glass adds a small amount of optical path that shifts focus rearward, which matters when you are setting the spacing between a field flattener and your sensor. If you are unsure whether your wheel, drawer or diagonal will take a mounted 2-inch filter, contact our team in Bolton with the model and we will confirm it.\u003c\/p\u003e\u003ch2\u003eGood to Know Before You Order\u003c\/h2\u003e\u003cp\u003eExplore Scientific publishes no shipping weight for this item, so we are confirming it on our own scales before the listing goes live. That is why it is currently unpublished. Contact us and we will give you a shipping figure for your address. Also worth setting expectations on: sulphur is the weakest of the three lines most narrowband imagers work with, so this channel will always need more integration time than hydrogen-alpha to reach the same depth, whatever the bandpass. Explore Scientific does not publish peak transmission, substrate material or a full out-of-band blocking range for this filter, and we will not invent those numbers; the individual test report supplied with the filter carries the measured curve for your copy. The delivery is the filter and that report, with no diagonal, wheel, adapter or camera included.\u003c\/p\u003e\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eDo I actually need a 2-inch filter?\u003c\/strong\u003e If your sensor is larger than about Four Thirds, or your filter wheel and drawer are built around 2-inch threads, yes. A 1.25-inch filter in front of an APS-C or full-frame chip will vignette the corners noticeably. If you are running a small mono camera, the 1.25-inch version does the same optical job for less.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs this usable visually?\u003c\/strong\u003e On a large aperture and a bright planetary nebula it can show real structure, and Explore Scientific does mention urban observers alongside astrophotographers for the S-II line. But 672 nm is deep in the red where the dark-adapted eye is weakest, so treat visual use as a bonus rather than the purpose.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy not go to 6.5 nm for more contrast?\u003c\/strong\u003e Because on a big sensor, a fast beam, and the faintest of the three lines, you would be paying twice: once in signal and once in field uniformity. The 6.5 nm version rewards slower optics, smaller fields and long integration. This one is the more forgiving instrument.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill it work with a colour camera?\u003c\/strong\u003e Only inefficiently. Bayer-array cameras dedicate roughly a quarter of their photosites to red, and the colour filters themselves attenuate what reaches them. Narrowband work of this kind belongs to monochrome sensors.\u003c\/p\u003e\u003ch2\u003eBottom Line\u003c\/h2\u003e\u003cp\u003eThis is the sulphur filter for a large sensor and a fast telescope, where uniform transmission across a wide field matters more than the last decibel of background rejection. It fits standard 2-inch threads, ships with its own measured test report, and behaves predictably from centre to corner. Contact us if you would like help deciding between this and the 6.5 nm version for your particular optics.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":53958705905775,"sku":"310110","price":249.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/310110_2.jpg?v=1785960889"},{"product_id":"explore-scientific-2-inch-sulphur-ii-6-5nm-nebula-filter","title":"Explore Scientific 2-inch Sulphur II 6.5nm Narrowband Nebula Filter","description":"\u003ch2\u003eProduct Overview\u003c\/h2\u003e\u003cp\u003eThis is the most specialised sulphur filter Explore Scientific offers in the 2-inch format: a 6.5 nm passband centred on the ionised sulphur emission line at 672 nm, in a mounted 2-inch cell. Explore Scientific describes the result as amazing for revealing nebulae in light-polluted urban areas, and frames the filter's job as absorbing interfering emission lines to deliver more contrast and detail for urban observers and astrophotographers. As with the rest of the range, an individual test report for the specific filter is part of the scope of delivery.\u003c\/p\u003e\u003ch2\u003eWho It's For\u003c\/h2\u003e\u003cp\u003eEverything in narrowband imaging is a negotiation between contrast and signal, and this filter sits at one extreme of it. Halving the passband relative to a 12 nm filter roughly halves the sky continuum you accumulate in a given exposure while leaving the nebular emission line untouched, so the target sits on a darker background and the contrast in the raw subframe is visibly better. That is exactly what you want when the sky itself is the problem: a white-zone back garden, a rising moon, a target that never climbs out of the light dome to the south.\u003c\/p\u003e\u003cp\u003eWhat you should be clear-eyed about is that this filter stacks the two hardest conditions in the range on top of each other. Sulphur is the weakest of the three lines commonly mapped in narrowband work, and 6.5 nm is the tightest window Explore Scientific puts on it. The result is a filter that demands things of your setup rather than accommodating it: enough aperture that the sulphur channel is not hopeless, a focal ratio around f\/5 or slower so the passband does not drift off the line in a steep light cone, a cooled monochrome camera with low read noise so that fifteen or twenty minute subframes actually pay, and a project measured in tens of hours rather than a single clear night. Buy it if you are already producing decent S-II data with a wider filter and you have decided the sky background is what stands between you and a better image. If you are still fighting for signal rather than fighting the sky, the 12 nm 2-inch version is the more sensible instrument.\u003c\/p\u003e\u003ch2\u003eKey Features \u0026amp; Design\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e6.5 nm passband, the narrowest sulphur window in the Explore Scientific 2-inch range\u003c\/li\u003e\n\u003cli\u003eCentred on the ionised sulphur emission line at 672 nm\u003c\/li\u003e\n\u003cli\u003eRoughly half the sky background of a 12 nm filter for the same nebular signal\u003c\/li\u003e\n\u003cli\u003eMounted 2-inch cell suited to large sensors, 2-inch filter wheels and 2-inch diagonals\u003c\/li\u003e\n\u003cli\u003eBlocks the artificial light that dominates urban skies, including sodium and mercury vapour lighting\u003c\/li\u003e\n\u003cli\u003eIndividual test report for your specific filter included\u003c\/li\u003e\n\u003cli\u003eIntended for planetary nebulae, emission nebulae and supernova remnants\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eFilter Design\u003c\/h2\u003e\u003cp\u003eThe narrower the window, the more the geometry of your optical system matters. A dielectric interference filter defines its passband for light arriving perpendicular to the coating, and the transmission curve moves toward shorter wavelengths as the angle of incidence grows. In a 2-inch filter feeding a large sensor there are two separate contributors to that angle: the convergence of the beam, set by your focal ratio, and the field position, since light destined for a corner of a full-frame chip crosses the filter differently from light headed for the centre. Both effects push the passband away from 672 nm. In a 12 nm filter that drift eats into the margin. In a 6.5 nm filter, with only about three nanometres either side of the peak to spare, the same drift can move the sulphur line onto the shoulder of the curve, where transmission falls away. The practical consequence is that this filter belongs on moderate focal ratios and rewards a well-collimated, well-spaced imaging train, and it is why the enclosed test report showing where your filter's centre wavelength actually landed is more than a nicety here.\u003c\/p\u003e\u003ch2\u003eRecommended Uses\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eDeep sulphur channels for mapped-colour imaging from heavily light-polluted sites\u003c\/li\u003e\n\u003cli\u003eMulti-night and multi-season projects on emission nebulae where S-II is the limiting channel\u003c\/li\u003e\n\u003cli\u003eImaging through moonlight, when sky background rather than target brightness sets the floor\u003c\/li\u003e\n\u003cli\u003eSupernova remnants and planetary nebulae photographed with large monochrome sensors\u003c\/li\u003e\n\u003cli\u003eModerate focal ratio refractors and reflectors with 2-inch filter wheels or drawers\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCompatibility and Accessory Notes\u003c\/h2\u003e\u003cp\u003eStandard 2-inch filter threads let this screw into a 2-inch nosepiece, a 2-inch star diagonal, the barrel of a 2-inch eyepiece, or most 2-inch filter wheels. It is not a fit for wheels designed around unmounted 36 mm or 50.8 mm discs, and the mounted cell is thicker than an unmounted disc, so check the clearance in a filter drawer before ordering. Mounted glass in the light path also shifts focus slightly rearward, which is worth allowing for when you set the distance between a field flattener or reducer and your sensor. If you are matching this to a hydrogen-alpha and an O-III filter, keeping the whole set at a similar bandwidth makes your exposure planning far easier to reason about. Our team in Bolton will confirm fit against your specific wheel or drawer if you send us the model.\u003c\/p\u003e\u003ch2\u003eGood to Know Before You Order\u003c\/h2\u003e\u003cp\u003eExplore Scientific publishes no shipping weight for this item, so we are confirming it on our own scales before the listing goes live. That is why it is currently unpublished. Contact us and we will give you a shipping figure for your address. Two honest caveats beyond that. This is not a visual filter: a 6.5 nm window at 672 nm passes far too little light for the eye, whatever your aperture. And Explore Scientific does not publish peak transmission, substrate specification or an out-of-band blocking range for this filter, so we do not quote figures we cannot source. The measured curve for your individual filter comes with it in the box. The delivery is the filter and that report; no wheel, adapter, diagonal or camera is included.\u003c\/p\u003e\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eHow does this differ from the 12 nm 2-inch S-II?\u003c\/strong\u003e Same line, same format, roughly half the window. You get a darker sky background and better raw contrast, and you pay for it with a filter that is less tolerant of fast optics, large fields and short exposures. The 12 nm is the general-purpose filter; this one is a specialist for bright skies and long projects.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat focal ratio does it want?\u003c\/strong\u003e Explore Scientific does not publish a limit. As a working guide, around f\/5 and slower is comfortable, and below roughly f\/4 the passband shift across the beam begins to cost you meaningful transmission at 672 nm. If your system sits near that boundary, contact us and we will work through it with you.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much total integration should I plan for?\u003c\/strong\u003e More than you would for hydrogen-alpha, typically by a factor of two or three on the same target. Sulphur is faint and a tight window is unforgiving, so treat this as a channel you build up across several nights.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill it cover a full-frame sensor?\u003c\/strong\u003e The 2-inch format is the right choice for large chips, though as with any filter placed in a converging beam close to the sensor, keep an eye on transmission uniformity in the corners at fast focal ratios.\u003c\/p\u003e\u003ch2\u003eBottom Line\u003c\/h2\u003e\u003cp\u003eThe 6.5 nm 2-inch S-II is the filter you buy when the sky is the obstacle and you have the aperture, the focal ratio and the patience to meet its terms. It rewards long integration and a well-sorted imaging train, and it will out-contrast a wider filter on any night with a bright background. If you want to talk through whether your rig is the right home for it, contact us and we will give you a straight answer.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":53958724976751,"sku":"310120","price":297.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/310120_2.jpg?v=1785960948"},{"product_id":"explore-scientific-2-inch-h-alpha-12nm-nebula-filter","title":"Explore Scientific 2-inch Hydrogen-Alpha 12nm Narrowband Nebula Filter","description":"\u003ch2\u003eProduct Overview\u003c\/h2\u003e\u003cp\u003eThe Explore Scientific 2-inch H-Alpha Nebula Filter pairs a 12 nm passband on the hydrogen emission line with a mounted 2-inch cell, so it covers large sensors and drops straight into 2-inch wheels, drawers and diagonals. Explore Scientific presents it as an answer to artificial light: it passes the hydrogen emission and blocks the interfering wavelengths, including the mercury and sodium vapour lighting that makes deep-sky work from a town so difficult. Explore Scientific specifies it for astrophotography, and each filter is supplied with an individual test report.\u003c\/p\u003e\u003ch2\u003eWho It's For\u003c\/h2\u003e\u003cp\u003eThis is the filter that stays in the wheel. Hydrogen-alpha is the brightest of the lines narrowband imagers work with, and 12 nm is a generous window, so the combination produces usable signal fast. That has a practical consequence that is easy to overlook when you are comparing bandpass numbers on a page: because the target is bright through this filter, you can work in three to five minute subframes rather than fifteen or twenty. Short subframes mean a satellite trail or a gust of wind costs you one frame instead of a quarter of an hour, and it means you can integrate meaningfully on a night that only offers ninety clear minutes. Under a 12 nm hydrogen window that is a real image; under a 3 nm sulphur window it is a test frame.\u003c\/p\u003e\u003cp\u003eThe 2-inch format is what makes it a wide-field instrument. On a full-frame or large APS-C monochrome camera behind a short focal length astrograph, you are covering several degrees of sky, and the light heading for the corners crosses the filter at a very different angle from the light heading for the centre. A wide passband is what keeps those two regions transmitting the hydrogen line equally, so mosaics stitch cleanly and gradients are genuinely sky gradients rather than filter artefacts. Choose this if you shoot wide fields at f\/4 to f\/6, if you build mosaics, if you want a hydrogen luminance layer for broadband colour work, or if you simply want the narrowband filter that asks the least of your mount, your sky and your available hours. If your sky is bright enough that the residual background under 12 nm is still what limits you, step to the 7 nm version instead.\u003c\/p\u003e\u003ch2\u003eKey Features \u0026amp; Design\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e12 nm passband on the hydrogen emission line at 656.3 nm\u003c\/li\u003e\n\u003cli\u003eMounted 2-inch cell for full-frame and large APS-C sensors, 2-inch wheels and 2-inch diagonals\u003c\/li\u003e\n\u003cli\u003eExplore Scientific states it blocks almost all mercury and sodium vapour lamp light\u003c\/li\u003e\n\u003cli\u003eWide enough to transmit evenly from field centre to corner on short focal length astrographs\u003c\/li\u003e\n\u003cli\u003eStrong enough signal to work in short subframes, which limits the cost of a spoiled frame\u003c\/li\u003e\n\u003cli\u003eIndividual test report for the specific filter included in the scope of delivery\u003c\/li\u003e\n\u003cli\u003eRecords red emission nebulae to their full extent in photographs taken from bright sites\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eFilter Design\u003c\/h2\u003e\u003cp\u003eThe passband comes from a dielectric interference stack rather than from dye or absorption glass, and the property that governs its behaviour in a real telescope is angular sensitivity. The interference condition that defines peak transmission is satisfied at progressively shorter wavelengths as light strikes the coating further from perpendicular, so the whole curve shifts blueward with angle. In a 2-inch filter mounted close to a large sensor, the range of angles present across the filter is set both by the focal ratio and by how far off-axis a given ray is headed. A 12 nm window is broad enough that even the most steeply inclined rays in an f\/4 cone at the corner of a full-frame chip still see 656.3 nm well inside the flat part of the transmission curve. That is the whole argument for a wider band at this aperture: it is not that narrower filters are worse in principle, it is that the geometry of a fast, wide system uses up the margin a narrow filter does not have.\u003c\/p\u003e\u003ch2\u003eRecommended Uses\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eWide-field hydrogen-alpha imaging on emission nebulae and supernova remnants\u003c\/li\u003e\n\u003cli\u003eMulti-panel mosaics, where consistent transmission across the frame matters most\u003c\/li\u003e\n\u003cli\u003eHydrogen luminance layers blended into broadband colour images\u003c\/li\u003e\n\u003cli\u003eContinuing to collect data through moonlight and from urban and suburban sites\u003c\/li\u003e\n\u003cli\u003eFast astrographs and Newtonians at f\/4 to f\/6 with large monochrome sensors\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCompatibility and Accessory Notes\u003c\/h2\u003e\u003cp\u003eThe cell uses the standard 2-inch filter thread and will screw into a 2-inch camera nosepiece, a 2-inch star diagonal, the barrel of a 2-inch eyepiece, or the carousel of most 2-inch filter wheels. It is not compatible with wheels built for unmounted 36 mm or 50.8 mm discs, and the mounted cell may be too thick for some slim filter drawers, so check that clearance first. Adding a mounted filter to the light path shifts focus slightly rearward, which matters when you are dialling in the spacing between a reducer or field flattener and your sensor. This filter is the usual first purchase in a 2-inch narrowband set, with matching Explore Scientific narrowband filters available in the same format. Send us the model of your wheel or drawer and our team in Bolton will confirm the fit before you order.\u003c\/p\u003e\u003ch2\u003eGood to Know Before You Order\u003c\/h2\u003e\u003cp\u003eExplore Scientific publishes no shipping weight for this item, so we are confirming it on our own scales before the listing goes live. That is why it is currently unpublished. Contact us and we will give you a shipping figure for your address. It is also worth being plain that Explore Scientific develops these hydrogen-alpha filters for photography, not for the eyepiece; a 12 nm window in the deep red gives the dark-adapted eye very little to work with, and you should not buy it as a visual nebula filter. Explore Scientific does not publish transmission, substrate or blocking figures on the product page, so we do not repeat numbers we cannot verify. The measured curve for your particular filter is in the enclosed test report. Delivery consists of the filter and that report, with no camera, wheel, diagonal or adapter included.\u003c\/p\u003e\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eShould I buy this or the 7 nm 2-inch hydrogen-alpha?\u003c\/strong\u003e Ask what limits your images. If it is the sky background, because you are shooting from a bright site or through a full moon, the 7 nm filter will help. If it is field size, focal ratio or available clear hours, the 12 nm filter will produce better data, and it is the more forgiving filter on fast optics.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use it visually?\u003c\/strong\u003e Not productively. Explore Scientific developed the hydrogen-alpha line of filters for astrophotography. For visual nebula observing, an O-III or a broadband nebula filter is the correct tool.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it work with a colour camera?\u003c\/strong\u003e Poorly. Only the red photosites of a Bayer sensor contribute, and their own colour filters attenuate the signal further. A monochrome camera gets the full benefit.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow long should my subframes be?\u003c\/strong\u003e Considerably shorter than for the fainter lines. Many imagers find three to five minutes per subframe sufficient with this filter on a cooled monochrome camera, which is one of its practical advantages over a narrower window.\u003c\/p\u003e\u003ch2\u003eBottom Line\u003c\/h2\u003e\u003cp\u003eThe 2-inch 12 nm hydrogen-alpha is the workhorse of a large-format narrowband set: bright, forgiving, even across a wide field, and productive on nights that would defeat a tighter filter. It is the one most imagers use the most. Contact us if you would like help deciding between this and the 7 nm version for your optics and your sky.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":53958752960623,"sku":"310130","price":242.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/310130_2.jpg?v=1785961005"},{"product_id":"explore-scientific-2-inch-h-alpha-7nm-nebula-filter","title":"Explore Scientific 2-inch Hydrogen-Alpha 7nm Narrowband Nebula Filter","description":"\u003ch2\u003eProduct Overview\u003c\/h2\u003e\u003cp\u003eThe Explore Scientific 2-inch H-Alpha Nebula Filter with a 7 nm passband is the tighter of the company's two 2-inch hydrogen filters. Explore Scientific describes what it does without hedging: it blocks all other colours and nearly all artificial light, letting through only the hydrogen emission lines, and the effect is that structure appears in photographs where an unfiltered frame looks empty. The company developed it exclusively for astrophotography and calls it a must for urban astrophotographers, noting that it is especially effective when the sky is slightly brightened. It is mounted in a 2-inch cell and supplied with an individual test report.\u003c\/p\u003e\u003ch2\u003eWho It's For\u003c\/h2\u003e\u003cp\u003eThe argument for narrowing the band is different for hydrogen than it is for sulphur or oxygen, and it is worth understanding why. Narrowing the window from 12 nm to 7 nm cuts the continuum background you collect by roughly forty percent while the emission line, which is a fraction of a nanometre wide, passes through as strongly as before. The image gets darker overall and the nebula does not, which is the entire point. The reason this is a comfortable trade with hydrogen specifically, and an uncomfortable one with sulphur, is that hydrogen-alpha is normally the strongest line in an emission nebula by a considerable margin. You have signal to spend, so spending some of it on contrast is a reasonable bargain rather than a sacrifice.\u003c\/p\u003e\u003cp\u003eThat makes this the hydrogen filter for people whose limiting factor is the sky rather than the target. If you image from a genuinely bright suburban or urban site, if you want to keep working within a few days of full moon, or if you are shooting targets that sit low over a city light dome, the 7 nm window keeps the background down where the 12 nm filter starts to fill in. It suits full-frame and large APS-C monochrome cameras in 2-inch wheels and drawers, and it is at its best on systems around f\/5 and slower, where the angular spread across a converging beam is modest enough that the tighter passband stays parked on 656.3 nm from centre to corner. On a very fast wide-field astrograph, or on nights where you only get an hour of sky, the 12 nm version will still serve you better.\u003c\/p\u003e\u003ch2\u003eKey Features \u0026amp; Design\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e7 nm passband on the hydrogen emission line at 656.3 nm\u003c\/li\u003e\n\u003cli\u003eAround forty percent less continuum sky background than a 12 nm filter for the same nebular signal\u003c\/li\u003e\n\u003cli\u003eMounted 2-inch cell for full-frame and large APS-C sensors and 2-inch filter wheels\u003c\/li\u003e\n\u003cli\u003eBlocks mercury and sodium vapour lamp emission, the dominant components of urban skyglow\u003c\/li\u003e\n\u003cli\u003eExplore Scientific developed it exclusively for astrophotography and recommends it for brightened skies\u003c\/li\u003e\n\u003cli\u003eNarrow enough to hold contrast through moonlight, wide enough to stay practical on moderate focal ratios\u003c\/li\u003e\n\u003cli\u003eIndividual test report for your specific filter included in the scope of delivery\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eFilter Design\u003c\/h2\u003e\u003cp\u003eThe transmission window is produced by a dielectric interference coating, and its two most important behaviours both follow from the same physics. First, the band is defined at normal incidence: light striking the coating at an angle satisfies the interference condition at a shorter wavelength, so the passband shifts toward the blue as the beam converges or as a ray heads for the edge of the field. Second, the size of that shift is the same in nanometres regardless of how wide your window is, which means it costs you proportionally more the tighter the filter. Seven nanometres is a well-judged compromise for a 2-inch filter: it leaves roughly three and a half nanometres of margin either side of the hydrogen line, enough that a moderate light cone and a large sensor still see the line near peak transmission, while removing a substantial slice of the background that a 12 nm filter admits. Push much narrower than this in a 2-inch cell close to a big chip and you begin trading real corner transmission for background suppression you may not need.\u003c\/p\u003e\u003ch2\u003eRecommended Uses\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eHydrogen-alpha imaging from light-polluted urban and suburban sites\u003c\/li\u003e\n\u003cli\u003eWorking through moonlit periods when broadband and wider narrowband filters lose contrast\u003c\/li\u003e\n\u003cli\u003eEmission nebulae, supernova remnants and hydrogen-rich star-forming regions on large sensors\u003c\/li\u003e\n\u003cli\u003eHigh-contrast hydrogen luminance layers for blending into broadband colour images\u003c\/li\u003e\n\u003cli\u003eModerate focal ratio refractors and reflectors with 2-inch filter wheels or drawers\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCompatibility and Accessory Notes\u003c\/h2\u003e\u003cp\u003eThe cell carries the standard 2-inch filter thread and screws into a 2-inch nosepiece, a 2-inch star diagonal, a 2-inch eyepiece barrel or the carousel of most 2-inch filter wheels. Wheels and drawers designed around unmounted 36 mm or 50.8 mm discs will not take a mounted cell, and slim drawers may not have the clearance, so it is worth confirming that before you order. Any mounted filter adds glass to the optical path and moves focus slightly rearward, which is a detail worth accounting for in the spacing between a reducer or field flattener and your sensor. If you are pairing this with sulphur and oxygen filters, remember that hydrogen tolerates a tighter window better than the other two lines do, so a mixed-bandwidth set is a defensible choice rather than an error, provided you plan your exposures accordingly. Our team in Bolton will confirm fit against your wheel, drawer or diagonal if you send us the model.\u003c\/p\u003e\u003ch2\u003eGood to Know Before You Order\u003c\/h2\u003e\u003cp\u003eExplore Scientific publishes no shipping weight for this item, so we are confirming it on our own scales before the listing goes live. That is why it is currently unpublished. Contact us and we will give you a shipping figure for your address. Beyond that: Explore Scientific is explicit that this filter was developed for astrophotography alone, and a 7 nm window in the deep red is of no practical use at the eyepiece. Explore Scientific also does not publish peak transmission, substrate details or a full out-of-band blocking specification for this filter, so we do not quote numbers we cannot source; the individual test report in the box gives the measured curve for the filter you receive. Delivery is the filter and that report, with no camera, wheel, adapter or diagonal included.\u003c\/p\u003e\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eWhy is 7 nm sensible for hydrogen when 6.5 nm is demanding for sulphur?\u003c\/strong\u003e Because the underlying signal is different. Hydrogen-alpha is usually much the strongest line in an emission nebula, so you can afford to trade some throughput for background suppression. Sulphur is the weakest, so the same trade leaves you scraping for signal. Bandwidth choices should follow line strength, not just the number on the box.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I image through a full moon with this?\u003c\/strong\u003e Within reason, yes, provided the moon is not close to your target. The narrower window is exactly what keeps moonlit continuum out of the frame, and it is the main reason to choose this over the 12 nm version.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs it too narrow for my f\/4 astrograph?\u003c\/strong\u003e Explore Scientific does not publish a focal ratio limit. As a practical guide, 7 nm is comfortable around f\/5 and slower and starts to lose corner transmission on very fast systems with large sensors. If you are near that boundary, contact us with your optics and sensor size and we will give you our honest read.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it need a monochrome camera?\u003c\/strong\u003e It works best with one. On a Bayer-array colour camera only the red photosites see the hydrogen line, and their own dyes cost you further transmission, so you are paying for a premium filter and using a quarter of your sensor.\u003c\/p\u003e\u003ch2\u003eBottom Line\u003c\/h2\u003e\u003cp\u003eThis is the hydrogen filter for imagers fighting a bright sky: tight enough to suppress the background that ruins urban and moonlit frames, but sitting on a line strong enough to absorb the cost. On a moderate focal ratio and a large monochrome sensor it is the version that produces the cleanest hydrogen data. Contact us if you would like help choosing between it and the 12 nm filter for your site and your optics.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":53958771114095,"sku":"310140","price":311.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/310140_2.jpg?v=1785961061"}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/collections\/optolong-sho-filter-kit-36-3nm-produkt__29193_category.jpg?v=1767588693","url":"https:\/\/ontariotelescope.com\/collections\/narrow-band-filters.oembed?page=2","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}