{"product_id":"svbony-sv227-sii-5nm-narrowband-filter-2in","title":"SVBONY SV227 SII 5nm Narrowband Filter - 2\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eCaptures Sulfur-II (SII) emission at a 672nm center wavelength\u003c\/li\u003e\n\u003cli\u003eExtremely narrow 5nm bandpass for maximum contrast\u003c\/li\u003e\n\u003cli\u003ePeak light transmission of ≥90% for strong signal\u003c\/li\u003e\n\u003cli\u003eOD5 blocking rejects light pollution and unwanted wavelengths\u003c\/li\u003e\n\u003cli\u003eStandard 2-inch format with M48x0.75 filter threads\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\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\u003eSVBONY SV227 2\" SII 5nm Narrowband CCD Filter for Deep Sky\u003c\/h2\u003e\n\u003cp\u003eThe SVBONY SV227 2\" SII 5nm Narrowband CCD Filter isolates the critical 672nm Sulfur-II emission line with a tight 5nm full width at half maximum (FWHM) for extreme-contrast imaging. With a peak transmittance of ≥90% and deep out-of-band blocking rated at OD5, the SV227 ensures a pure signal from emission nebulae reaches your sensor. The filter is built on a 1.85mm thick substrate with 1\/4λ surface parallelism and fits standard 2-inch filter wheels via its M48x0.75 thread.\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\u003eThe 5nm Bandpass: Isolating the 672nm SII Line\u003c\/h3\u003e\n\u003cp\u003eBy restricting the incoming light to a narrow 5nm window centered on the 672nm SII line, the SV227 dramatically increases the contrast of emission nebulae against the skyglow background. This narrow bandpass is significantly more effective at rejecting light pollution from streetlights and moonlight than wider filters, darkening the sky background and allowing faint structural details to emerge during long exposures.\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\u003eOptical Precision: ≥90% Transmission with OD5 Blocking\u003c\/h3\u003e\n\u003cp\u003eA narrow filter is only effective if it transmits the light you want while rejecting everything else. The SV227 achieves a high peak transmittance of ≥90% within its passband, ensuring that valuable photons from your target aren't lost. Simultaneously, its OD5 blocking rating attenuates unwanted wavelengths by a factor of 100,000, delivering a clean signal free of IR contamination and reflected halos, which is critical for producing sharp stars and clean nebulosity.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSubstrate Quality:\u003c\/strong\u003e The 1.85mm substrate with a 1\/4λ surface parallelism rating ensures that the filter will not introduce distortions into your optical train.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eClear Aperture:\u003c\/strong\u003e A 44mm clear aperture minimizes the risk of vignetting, even with fast optical systems or large-format sensors.\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\u003eThe SV227 in SHO Imaging: Completing the Hubble Palette\u003c\/h3\u003e\n\u003cp\u003eThe SV227 is the essential \"S\" channel for creating tricolor narrowband images in the popular Hubble Palette (SHO). When combined with H-alpha and OIII filters of a similar 5nm bandpass, it allows you to assign each emission line to a different color channel (SII=Red, Ha=Green, OIII=Blue) to reveal the complex chemical composition of targets like the Pillars of Creation in the Eagle Nebula (M16).\u003c\/p\u003e\n\u003cp\u003eThe shared 5nm bandpass across your filter set ensures that star sizes are consistent between channels, simplifying post-processing and resulting in a more refined final image. The SV227's M48x0.75 thread makes it a direct fit for any standard 2-inch filter wheel or drawer.\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 main purpose of the SVBONY SV227 SII filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe SVBONY SV227 is a specialized narrowband filter for astrophotography. It is designed to isolate the \u003cstrong\u003eSulfur-II (SII) emission line at 672nm\u003c\/strong\u003e, which is prominent in many emission nebulae. This allows you to capture high-contrast images of these objects, even from light-polluted locations, and is a critical component for creating \"Hubble Palette\" color images.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the SV227's 5nm bandpass compare to a 7nm filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA \u003cstrong\u003e5nm bandpass\u003c\/strong\u003e is narrower than a 7nm one, offering superior rejection of light pollution and higher contrast on faint nebulae. The trade-off is that it requires slightly longer exposure times to achieve the same signal level. For heavily light-polluted skies or for imagers seeking maximum detail, the 5nm bandpass of the SV227 is the better choice.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the SVBONY SV227 work for imaging the Soul Nebula (IC 1848) with my monochrome camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. The Soul Nebula is rich in glowing ionized gas, including Sulfur-II. Using the SVBONY SV227 with a monochrome camera is the ideal way to capture the faint, intricate structures within this nebula that are often lost in broadband or wider-filter images. It will provide the \"S\" data needed for a full SHO color composite.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 5nm bandpass of the SV227 suitable for my f\/5 Newtonian telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, a 5nm filter like the SV227 is generally fine for systems down to f\/4. In very fast optical systems (f\/4 and faster), narrowband filters can experience a slight shift in their center wavelength. However, at f\/5, the SV227 will perform very well, providing excellent contrast without significant band-shifting issues.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does OD5 blocking mean for my images with the SV227 filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eOD5 (Optical Density 5)\u003c\/strong\u003e means the filter blocks out-of-band light by a factor of 100,000 (10^5). This is a very high level of rejection that ensures only the desired 672nm SII light reaches your sensor. It prevents star bloat from infrared (IR) light and eliminates gradients from nearby light pollution sources, resulting in a cleaner, higher-contrast image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the SVBONY SV227 filter for visual observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this filter is not recommended for visual use. The 5nm bandpass is extremely restrictive and will make the view through an eyepiece far too dim to see anything. Narrowband filters like the SV227 are designed specifically for long-exposure astrophotography with sensitive monochrome or color cameras.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eSII (Sulfur-II) Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSize\u003c\/td\u003e\n\u003ctd\u003e2-Inch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCenter Wavelength (CWL)\u003c\/td\u003e\n\u003ctd\u003e672nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandpass (FWHM)\u003c\/td\u003e\n\u003ctd\u003e5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePeak Transmittance\u003c\/td\u003e\n\u003ctd\u003e≥90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking\u003c\/td\u003e\n\u003ctd\u003e≥OD5 over 300-1000nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eClear Aperture\u003c\/td\u003e\n\u003ctd\u003e44mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Thickness\u003c\/td\u003e\n\u003ctd\u003e1.85mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Quality\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Parallelism\u003c\/td\u003e\n\u003ctd\u003e1\/4λ\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism (Angle)\u003c\/td\u003e\n\u003ctd\u003e30\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eThread\u003c\/td\u003e\n\u003ctd\u003eM48x0.75\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSingle Thread\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet Weight\u003c\/td\u003e\n\u003ctd\u003e12.5g \/ 0.44oz\u003c\/td\u003e\n\u003c\/tr\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\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/svbony-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eSVBONY 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"SVBONY","offers":[{"title":"Default Title","offer_id":52861237100829,"sku":"SV-W9187DA","price":93.33,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/SVBONY-SV227-2-SII-5nm-Narrowband-CCD-Filter-for-Deep-Sky-1_2a8aa192-1666-4ce7-b82b-c908d4dc5980.jpg?v=1788883710","url":"https:\/\/davidastro.com\/fr-us\/products\/svbony-sv227-sii-5nm-narrowband-filter-2in","provider":"David Astro","version":"1.0","type":"link"}