{"product_id":"explore-scientific-310115","title":"Explore Scientific Nebula Filter S-II 1.25-inch 12nm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eIsolates the ionized sulfur (S-II) emission line at 672nm\u003c\/li\u003e\n\u003cli\u003eFeatures a 12nm bandpass to increase contrast\u003c\/li\u003e\n\u003cli\u003eStandard 1.25-inch filter format\u003c\/li\u003e\n\u003cli\u003eIdeal for both visual observation and astrophotography\u003c\/li\u003e\n\u003cli\u003eIncludes an individual test report for quality assurance\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eNebula Filter S-II 1.25-inch 12nm\u003c\/h2\u003e\n\u003cp\u003eThe Explore Scientific S-II Nebula Filter isolates a specific 12nm band of red light centered on the 672nm wavelength, targeting the emission line of ionized sulfur. This 1.25-inch filter is engineered to dramatically increase the contrast of specific deep-sky objects by rejecting light pollution from artificial sources and the unwanted glow of natural skyglow.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eIsolating the 672nm S-II Line: A 12nm Passband for High Contrast\u003c\/h3\u003e\n\u003cp\u003eMany of the most sought-after deep-sky targets are emission nebulae, which glow at discrete wavelengths corresponding to their chemical makeup. This filter is designed to transmit only the light from ionized sulfur at 672nm, a key component in the structure of objects like the Eagle Nebula (M16) and the Lagoon Nebula (M8). By blocking nearly all other wavelengths, the filter renders the faint structure of the nebula against a much darker sky background.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e12nm Bandpass:\u003c\/strong\u003e This width is an excellent compromise, offering a significant contrast boost over broadband filters while being more forgiving for visual use than ultra-narrow 3nm or 5nm filters. It reveals details in emission nebulae, planetary nebulae, and supernova remnants that are otherwise lost to light pollution.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIndividual Test Report:\u003c\/strong\u003e Each Explore Scientific filter includes an individual test certificate, guaranteeing that its bandpass and transmission characteristics meet the 12nm specification. This ensures you receive a filter that performs as advertised.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eA 1.25-Inch Filter for Visual and Photographic Deep Sky\u003c\/h3\u003e\n\u003cp\u003eDesigned in the universal 1.25-inch format, this S-II filter threads directly into standard eyepieces and filter wheels. For visual observers, it can make the difference between seeing a faint nebula and missing it entirely, especially from suburban skies. The contrast enhancement can reveal intricate wisps and structural details that are normally invisible.\u003c\/p\u003e\n\u003cp\u003eFor astrophotographers, the S-II filter is a cornerstone of narrowband imaging. It allows you to capture one of the three key emission lines (along with H-alpha and O-III) used to create detailed, full-color images from even heavily light-polluted locations. Capturing S-II data is essential for producing images in popular palettes like the \"Hubble Palette\" (SHO).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the primary purpose of the Explore Scientific 12nm S-II filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary purpose of this filter is to increase the contrast of emission nebulae that glow in the light of \u003cstrong\u003eionized sulfur (S-II)\u003c\/strong\u003e. It achieves this by selectively passing a 12nm-wide band of light centered at the 672nm wavelength while blocking out light pollution and other unwanted wavelengths, resulting in a darker sky background and more visible nebular detail.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the 12nm S-II filter help in light-polluted skies?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eArtificial lighting, like streetlights, primarily emits light across a broad spectrum. The Explore Scientific S-II filter blocks almost all of this light, only allowing the specific 672nm wavelength from the nebula to pass through. This effectively subtracts the light pollution from the view, making faint objects visible even from urban or suburban locations.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill this 1.25-inch S-II filter work with my color camera for astrophotography?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile you can use this filter with a color camera, it is not ideal. The camera's Bayer matrix has red, green, and blue pixels, and this filter only passes deep red light that will be recorded by the red pixels. For best results, narrowband filters like this S-II are used with \u003cstrong\u003emonochrome astronomy cameras\u003c\/strong\u003e, allowing you to capture separate data for each emission line (S-II, H-alpha, O-III) and combine them later into a full-color image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat objects show the most detail with the 12nm S-II filter, for example, the Eagle Nebula (M16)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Eagle Nebula (M16) is an excellent target, as its famous \"Pillars of Creation\" are rich in ionized sulfur. Other strong S-II targets include:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eThe Lagoon Nebula (M8)\u003c\/li\u003e\n\u003cli\u003eThe Omega\/Swan Nebula (M17)\u003c\/li\u003e\n\u003cli\u003eThe Rosette Nebula (NGC 2237)\u003c\/li\u003e\n\u003cli\u003eSupernova remnants like the Veil Nebula (NGC 6960)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eI have an 8\" SCT. Is a 12nm S-II filter a good choice for visual observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, it's a very good choice. In an 8\" SCT, you have enough aperture to gather sufficient light for visual narrowband observing. The 12nm bandpass provides a strong contrast boost without making the image overly dim, which can be an issue with tighter 3nm or 5nm filters for visual use. It will help you see structure in planetary and emission nebulae that would otherwise be washed out.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is an individual test report included with the Explore Scientific S-II filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe individual test report is your assurance of quality control. It certifies that your specific filter has been tested and meets the advertised specifications for its central wavelength (672nm) and bandpass (12nm). This guarantees that the filter will perform as expected, effectively isolating the desired S-II emission line.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/explore-scientific-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eExplore Scientific Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":52909386727709,"sku":"ES-310115","price":224.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/ExploreScientific-Nebula-Filter-S-II-1-25-inch-12nm-1_fb1392c6-04ef-4c06-a312-3b545f36c956.jpg?v=1789061546","url":"https:\/\/davidastro.com\/fr\/products\/explore-scientific-310115","provider":"David Astro","version":"1.0","type":"link"}