{"product_id":"touptek-sho-4nm-filters","title":"Touptek SHO 4nm Filters for Astrophotography","description":"\u003ch2\u003eTouptek SHO 4nm Filters for Astrophotography\u003c\/h2\u003e\n\u003cp\u003e\u003cspan style=\"font-weight: 600; color: #3860ea;\"\u003eNarrowband filters\u003c\/span\u003e are essential accessories in astrophotography used to isolate specific wavelength emission lines and enhance the signal-to-noise ratio of your target—especially for capturing breathtaking emission nebulae.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eToupTek HSO narrowband filters\u003c\/b\u003e are precisely tuned to the three main ionized emission lines found in star-forming regions:\u003cspan style=\"color: #e04156; font-weight: 600;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eHα (656.3nm)\u003c\/li\u003e\n\u003cli\u003eSII (671.6nm)\u003c\/li\u003e\n\u003cli\u003eOIII (500.7nm)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cdiv style=\"margin-top: 12px;\"\u003eBy using these filters, you can effectively block urban light pollution and background stray light, dramatically enhance signal contrast, and bring out incredible detail—empowering you to achieve \u003cb\u003eHubble-like color mixing (SHO synthesis)\u003c\/b\u003e in your astrophotography.\u003c\/div\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch4\u003ePrecise Band Control \u0026amp; Enhanced Detail Resolution\u003c\/h4\u003e\n\u003cp\u003eThe precise narrowband design effectively suppresses background noise while highlighting the emission structures of different elements, resulting in clearer celestial stratification and enhanced detail gradation.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cspan style=\"text-decoration: underline;\"\u003e\u003cstrong\u003eHα filter: Central wavelength 656.3nm, FWHM 4nm. \u003c\/strong\u003e\u003c\/span\u003eOptimized for hydrogen ionization regions, this filter serves as the primary channel for capturing nebular morphology.\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"text-decoration: underline;\"\u003e\u003cstrong\u003eOIII filter:\u003c\/strong\u003e\u003c\/span\u003e\u003cstrong\u003e Central wavelength 500.7nm \u003c\/strong\u003e\u003cstrong\u003e(OIII emission line), FWHM 4nm.\u003c\/strong\u003e Designed to reveal high-energy excitation zones, particularly effective for visualizing blue-green nebular details.\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"text-decoration: underline;\"\u003e\u003cstrong\u003eSII filter: Central wavelength 671.6nm, FWHM 4nm. \u003c\/strong\u003e\u003c\/span\u003eEnhances detection of faint signals and reveals structural stratification through ionized sulfur distribution. When combined with Hα, significantly improves image contrast.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eHigh-Quality Quartz Glass, High Transparency and Purity\u003c\/h4\u003e\n\u003cp\u003eThe entire series of ToupTek Astro filters utilize high-quality colorless transparent quartz glass, with \u0026gt;90% high transmittance, high purity, exceptional blue-violet band transmission, and outstanding thermal stability—ideal for various demanding astronomical imaging applications.\u003c\/p\u003e\n\u003ch4\u003eIAD Dense Coating, Durable and Stable\u003c\/h4\u003e\n\u003cp\u003eUsing IAD (Ion Assisted Deposition) coating technology, which is more costly than conventional vacuum evaporation but produces denser and more uniform coatings that are durable, corrosion-resistant, and have superior environmental stability.\u003c\/p\u003e\n\u003ch4\u003ePrecision Coating, Significantly Suppresses Halos\u003c\/h4\u003e\n\u003cp\u003eToupTek Astro filters employ a proprietary multi-layer system: a single-sided cutoff coating, front surface AR anti-reflection coating, and edge blackening treatment. This combination effectively minimizes internal reflections and stray light while ensuring coating integrity and extended service life.\u003c\/p\u003e\n\u003ch4\u003eHigh Optical Cutoff Depth, Restores Natural Colors\u003c\/h4\u003e\n\u003cp\u003eAll channel filters have a cutoff depth of OD≥5.0, effectively blocking non-target spectral regions, avoiding band crosstalk and color cast, resulting in accurate and natural color reproduction.\u003c\/p\u003e\n\u003ch4\u003eMatte Black Edge Coating, Easy Installation\u003c\/h4\u003e\n\u003cp\u003eThe filter edge is coated with a black matte treatment to minimize stray light, which ensures transmittance, reduces glare, and enhances image contrast.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e36mm filters: The telescope-facing side has an inward-extending blackened border for quick orientation identification.\u003c\/li\u003e\n\u003cli\u003e1.25\" \u0026amp; 2\" filters: Feature threaded aluminum alloy frames for direct screw-in installation, ensuring fast and tool-free mounting.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eHighly Compatible\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eAll filters use a single-piece, glue-free structure.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e36mm: Recommended for APS-C and smaller cameras.\u003c\/li\u003e\n\u003cli\u003e1.25\": Recommended for cameras with a 1-inch or smaller sensor.\u003c\/li\u003e\n\u003cli\u003e2\": Recommended for full-frame and smaller cameras.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCompatible with various brands on the market featuring 7-hole 36mm, 8-hole 1.25-inch, and 5-hole 2-inch electric filter wheels, offering a wider range of compatibility options.\u003c\/p\u003e\n\u003ch4 style=\"margin-top: 12px;\"\u003eSpectrum\u003c\/h4\u003e\n\u003ch3 style=\"margin-top: 12px;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0652\/6245\/2965\/files\/HSO-Spectrogram-01.webp?v=1772823218\" alt=\"\"\u003e\u003c\/h3\u003e\n\u003ch3 style=\"margin-top: 12px;\"\u003e\u003c\/h3\u003e\n\u003ch3 style=\"margin-top: 12px;\"\u003eTechnical Specifications\u003c\/h3\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eSize\u003c\/th\u003e\n\u003cth\u003e36mm (unframed) \/ 2”\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eGlass Thickness\u003c\/td\u003e\n\u003ctd\u003e2mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-alpha filter\u003c\/td\u003e\n\u003ctd\u003eCentral wavelength 656.3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSII filter\u003c\/td\u003e\n\u003ctd\u003eCentral wavelength 671.6nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOIII filter\u003c\/td\u003e\n\u003ctd\u003eCentral wavelength 500.7nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmittance\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFWHM (36mm)\u003c\/td\u003e\n\u003ctd\u003eH-alpha (4nm) \/ SII (4nm) \/ OIII (4nm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eGlass Material\u003c\/td\u003e\n\u003ctd\u003eQuartz glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFrame Material\u003c\/td\u003e\n\u003ctd\u003eAluminum Alloy\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Treatment\u003c\/td\u003e\n\u003ctd\u003eDouble-sided high-precision optical polishing\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating Technology\u003c\/td\u003e\n\u003ctd\u003eIAD (Ion Assisted Deposition)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating System Design\u003c\/td\u003e\n\u003ctd\u003eAR anti-reflection coating + quartz glass + precision cutoff coating layer\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOD\u003c\/td\u003e\n\u003ctd\u003e≥5.0\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003c\/p\u003e\n\u003ch3 style=\"margin-top: 12px;\"\u003eIn the box\u003c\/h3\u003e\n\u003cdiv style=\"margin-top: 12px;\"\u003e4nm SHO Filters, in selected size : \u003c\/div\u003e\n\u003cul\u003e\n\u003cli\u003e36mm\u003c\/li\u003e\n\u003cli\u003e2''\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cdiv style=\"margin-top: 12px;\"\u003e\n\u003ch3\u003e\n\u003cspan\u003eWarranty \u0026amp; Manual\u003c\/span\u003e\u003cspan\u003e\u003c\/span\u003e\n\u003c\/h3\u003e\n\u003cp\u003e\u003cspan\u003e\u003ca rel=\"noopener\" href=\"https:\/\/www.touptek-astro.com\/sales_policy\/\" target=\"_blank\"\u003e\u003cstrong data-end=\"650\" data-start=\"615\"\u003eToupTek 2 year Warranty \u003c\/strong\u003e\u003c\/a\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Touptek","offers":[{"title":"36mm \/ Ha","offer_id":48506947174629,"sku":"TOU-SHO4-Ha-36","price":251.0,"currency_code":"CAD","in_stock":true},{"title":"36mm \/ SII","offer_id":48506947207397,"sku":"TOU-SHO4-SII-36","price":251.0,"currency_code":"CAD","in_stock":true},{"title":"36mm \/ OIII","offer_id":48506947240165,"sku":"TOU-SHO4-OIII-36","price":251.0,"currency_code":"CAD","in_stock":true},{"title":"36mm \/ SHO Filter Set","offer_id":48506947272933,"sku":"TOU-SHO4-SET36","price":671.0,"currency_code":"CAD","in_stock":true},{"title":"2'' \/ Ha","offer_id":48506947305701,"sku":"TOU-SHO4-Ha-2","price":293.0,"currency_code":"CAD","in_stock":true},{"title":"2'' \/ SII","offer_id":48506947338469,"sku":"TOU-SHO4-SII-2","price":293.0,"currency_code":"CAD","in_stock":true},{"title":"2'' \/ OIII","offer_id":48506947371237,"sku":"TOU-SHO4-OIII-2","price":293.0,"currency_code":"CAD","in_stock":true},{"title":"2'' \/ SHO Filter Set","offer_id":48506947404005,"sku":"TOU-SHO4-SET2","price":834.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0652\/6245\/2965\/files\/SHO_2_6.5_filter.webp?v=1772824288","url":"https:\/\/astronomyplus.com\/products\/touptek-sho-4nm-filters","provider":"Astronomy Plus – Telescopes \u0026 Astrophotography Canada","version":"1.0","type":"link"}