{"title":"Filtres à bande étroite 5nm SVBONY SV227","description":"\u003cp\u003eLes filtres SVBONY SV227 sont des filtres à bande étroite de 5nm qui isolent les raies d'émission H-alpha, OIII et SII des nébuleuses, en bloquant l'essentiel de la pollution lumineuse et de la lumière de la Lune. Chaque raie existe en filtre monté 2\", et un jeu SHO réunit les trois en 1.25\" pour les petits capteurs et les roues à filtres.\u003c\/p\u003e\u003cp\u003eIls s'adressent aux astrophotographes en caméra monochrome qui réalisent des images en palette Hubble des nébuleuses en émission sous un ciel urbain ou périurbain.\u003c\/p\u003e","products":[{"product_id":"svbony-sv227-sho-5nm-h-alpha-oiii-sii-narrowband-filter-set-125in","title":"SVBONY SV227 SHO 5nm H-Alpha OIII SII Narrowband Filter Set - 1.25\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eComplete 1.25-inch SHO (SII, H-Alpha, OIII) filter set\u003c\/li\u003e\n\u003cli\u003eTight 5nm bandpass for high-contrast imaging\u003c\/li\u003e\n\u003cli\u003ePeak transmission rate of ≥90% at key wavelengths\u003c\/li\u003e\n\u003cli\u003eOD5 blocking of light from 300-1000nm\u003c\/li\u003e\n\u003cli\u003e1\/4λ surface parallelism for sharp stars\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 1.25\" SHO 5nm Narrowband Filter Set\u003c\/h2\u003e\n\u003cp\u003eThe SVBONY SV227 1.25\" SHO 5nm Narrowband Filter Set delivers the essential tools for creating high-contrast Hubble Palette images of deep-sky emission nebulae. This complete set isolates the critical emission lines of Sulfur-II at 671.6nm, Hydrogen-alpha at 656.3nm, and Oxygen-III at 500.7nm with a tight 5nm bandpass. With a peak transmission of ≥90% and OD5 blocking across the 300-1000nm spectrum, these filters capture faint nebula details while aggressively rejecting light pollution and moonlight.\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\u003eIsolate Key Nebula Emissions with a 5nm Bandwidth\u003c\/h3\u003e\n\u003cp\u003eThe core of narrowband imaging is isolating the specific wavelengths of light emitted by ionized gases in space. The SV227 set provides three filters precisely centered on these lines: 656.3nm for H-alpha, 500.7nm for OIII, and 671.6nm for SII. A narrow 5nm bandpass dramatically increases contrast by rejecting continuum emission from stars and suppressing skyglow, making faint structures within nebulae like the Pillars of Creation in the Eagle Nebula (M16) stand out against a dark background.\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\u003e≥90% Peak Transmission and 1\/4λ Surface Parallelism\u003c\/h3\u003e\n\u003cp\u003eHigh transmission and optical precision are critical for capturing clean data. The SV227 filters ensure that over 90% of the targeted narrowband light reaches your sensor, minimizing exposure times. Each filter is polished to a 1\/4λ surface parallelism, which prevents the introduction of astigmatism or other aberrations, keeping star shapes tight and round across the entire 26mm clear aperture.\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\u003eOD5 Blocking for Imaging Under Light-Polluted Skies\u003c\/h3\u003e\n\u003cp\u003eFor imagers in urban or suburban locations, aggressive blocking of unwanted light is non-negotiable. The SV227 filters provide an optical density (OD) of 5, which blocks out 99.999% of all light outside the 5nm passband, from 300nm to 1000nm. This deep blocking effectively eliminates gradients from streetlights, moonlight, and general skyglow, allowing you to capture clean, high-signal data even under compromised sky conditions.\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\u003e1.85mm Substrate with M28.5x0.6 Threads\u003c\/h3\u003e\n\u003cp\u003eBuilt for reliability, each SV227 filter uses a 1.85mm thick glass substrate housed in a CNC-machined 6061T aluminum alloy cell. The standard M28.5x0.6 male threads ensure compatibility with any 1.25-inch filter wheel or drawer. The consistent 1.85mm thickness across the set helps maintain focus between filter changes, reducing the need for constant refocusing throughout an imaging session.\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\u003eWhy Choose a 5nm Filter Set Over Wider Bandpasses?\u003c\/h3\u003e\n\u003cp\u003eWhile wider filters (like 7nm or 12nm) can allow for slightly shorter sub-exposures, a 5nm bandpass offers a distinct advantage in contrast. The tighter window rejects more of the unwanted light immediately surrounding the emission line, which results in a darker sky background and smaller, more controlled stars. This trade-off makes the 5nm SV227 set an excellent choice for imagers prioritizing maximum detail and contrast, especially from light-polluted locations.\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 advantage of the SVBONY SV227 5nm filter set?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary advantage is its tight \u003cstrong\u003e5nm bandpass\u003c\/strong\u003e. This provides extremely high contrast by isolating the specific H-alpha, OIII, and SII emission lines while rejecting nearly all other light, including light pollution and starlight. This results in a darker sky background and more prominent nebula detail compared to wider filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the SVBONY SV227 5nm filters perform on the Orion Nebula (M42) from a light-polluted suburb?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe SV227 filters are ideal for this scenario. The Orion Nebula (M42) is rich in H-alpha and OIII emissions. The \u003cstrong\u003eOD5 blocking\u003c\/strong\u003e will eliminate the vast majority of your suburban skyglow, and the 5nm bandpass will separate the faint, intricate structures of the nebula from the bright stars of the Trapezium, allowing you to capture far more detail than is possible with broadband or wider narrowband filters.\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 SHO set with my color camera and 80mm f\/6 refractor?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile technically possible, this set is designed and optimized for \u003cstrong\u003emonochrome astronomy cameras\u003c\/strong\u003e. Using these filters with a one-shot color (OSC) camera is highly inefficient, as the camera's color filter array will block most of the light that passes through the narrowband filter. For the best results and to create Hubble Palette images, you should pair the SV227 set with a monochrome camera and a filter wheel.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eAre the SVBONY SV227 filters parfocal with each other?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe filters in the SV227 set are manufactured to be nearly parfocal. They all use the same \u003cstrong\u003e1.85mm substrate thickness\u003c\/strong\u003e, which means that any focus shift when switching between the H-alpha, OIII, and SII filters should be minimal. This saves time during an imaging session as you won't need to perform a major refocus after every filter change.\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 the SV227 filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eOD5\u003c\/strong\u003e stands for Optical Density 5. This is a logarithmic scale meaning the filters block 10^5, or 100,000 times, the amount of unwanted light. In practical terms, it means they transmit only 0.001% of light outside their specified passband across a wide spectrum from 300nm to 1000nm, ensuring exceptional rejection of light pollution and moonlight.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy does the SVBONY SV227 set include three separate storage cases?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAs listed in the box contents, each of the three filters (H-alpha, SII, OIII) comes with its own protective \u003cstrong\u003ePP Storage Case\u003c\/strong\u003e. This prevents the filters from scratching or rubbing against each other during transport or storage and makes it easy to identify and handle them individually without exposing the others to dust or fingerprints.\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\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eSVBONY\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eProduct Name\u003c\/td\u003e\n\u003ctd\u003eSII \u0026amp; OIII \u0026amp; H-Alpha Filter Set\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSKU\u003c\/td\u003e\n\u003ctd\u003eW9187A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Size\u003c\/td\u003e\n\u003ctd\u003e1.25-Inch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandwidth\u003c\/td\u003e\n\u003ctd\u003e5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission Wavelengths\u003c\/td\u003e\n\u003ctd\u003e671.6nm (SII), 656.3nm (H-Alpha), 500.7nm (OIII)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePeak Transmission\u003c\/td\u003e\n\u003ctd\u003e≥90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Strength\u003c\/td\u003e\n\u003ctd\u003eOD5 @ 300-1000nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCut-off Depth\u003c\/td\u003e\n\u003ctd\u003eAverage ≥ OD5\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eClear Aperture\u003c\/td\u003e\n\u003ctd\u003e26mm\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\u003c\/td\u003e\n\u003ctd\u003e30\"\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\u003eThreads\u003c\/td\u003e\n\u003ctd\u003eM28.5x0.6 (Single Male Thread)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaterial\u003c\/td\u003e\n\u003ctd\u003e6061T Aluminum Alloy\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCell Finish\u003c\/td\u003e\n\u003ctd\u003eCNC Machined, Black Anodized\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Dimensions\u003c\/td\u003e\n\u003ctd\u003eΦ31.75 x 7mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet Weight (per filter)\u003c\/td\u003e\n\u003ctd\u003e15g\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet Weight (set)\u003c\/td\u003e\n\u003ctd\u003e140g\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\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003e1.25\" H-alpha Filter (5nm)\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003e1.25\" SII Filter (5nm)\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003e1.25\" OIII Filter (5nm)\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003ePP Storage Cases\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 3\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\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":52861237068061,"sku":"SV-W9187A","price":235.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/SVBONY-SV227-1-25-SHO-5nm-Narrowband-Filter-Set-for-Deep-Sky-1_eea5be8f-ad97-4327-a6bb-e8e103fa63cc.jpg?v=1788883698"},{"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":131.0,"currency_code":"CAD","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"},{"product_id":"svbony-sv227-h-alpha-5nm-narrowband-filter-2in","title":"SVBONY SV227 H-Alpha 5nm Narrowband Filter - 2\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eIsolates the 656.3nm H-Alpha wavelength\u003c\/li\u003e\n\u003cli\u003eAggressive 5nm Full Width at Half Maximum (FWHM) bandpass\u003c\/li\u003e\n\u003cli\u003ePeak transmittance of ≥90% for high signal throughput\u003c\/li\u003e\n\u003cli\u003eDeep ≥OD5 blocking of unwanted wavelengths from 300-1000nm\u003c\/li\u003e\n\u003cli\u003eStandard 2-inch (M48x0.75 thread) housing\u003c\/li\u003e\n\u003cli\u003e44mm clear aperture minimizes vignetting on larger sensors\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\" H-Alpha 5nm Narrowband CCD Filter\u003c\/h2\u003e\n      \u003cp\u003eThe SVBONY SV227 2\" H-Alpha 5nm Narrowband CCD Filter isolates the critical 656.3nm hydrogen-alpha emission line with a tight 5nm bandpass for maximum contrast. With peak transmittance rated at ≥90% and deep out-of-band blocking of ≥OD5 across the 300-1000nm range, this filter passes nebula signal while aggressively rejecting light pollution. The optical substrate is polished to a 1\/4λ surface parallelism, ensuring that the high resolution of your telescope is preserved in the final image.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eIsolating H-Alpha: The 5nm Bandpass at 656.3nm\u003c\/h3\u003e\n      \u003cp\u003eThe core of the SV227 is its ability to isolate a very specific slice of the red spectrum. The 5nm FWHM (Full Width at Half Maximum) is narrow enough to dramatically darken skyglow from city lights and moonlight, causing the faint structures within emission nebulae like the Heart Nebula (IC 1805) or Veil Nebula (NGC 6960) to stand out with stark contrast. Centered precisely on the 656.3nm H-alpha line, it captures the most dominant wavelength emitted by these deep-sky targets.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eOptical Integrity: ≥90% Transmission and OD5 Blocking\u003c\/h3\u003e\n      \u003cp\u003eA narrowband filter is only as good as its signal efficiency and its ability to block unwanted light. The SV227's coatings achieve a peak transmittance of ≥90%, ensuring that the faint H-alpha signal you're collecting isn't lost. Just as importantly, its ≥OD5 blocking rejects off-band light by a factor of 100,000, preventing bloated stars and washed-out backgrounds from compromising your long exposures.\u003c\/p\u003e\n        \u003cul\u003e\n            \u003cli\u003e\n\u003cstrong\u003e1\/4λ Surface Parallelism:\u003c\/strong\u003e Advanced polishing ensures the filter will not introduce distortions or degrade the sharpness of your optical system.\u003c\/li\u003e\n            \u003cli\u003e\n\u003cstrong\u003e1.85mm Substrate:\u003c\/strong\u003e The thin glass substrate helps minimize focus shift when switching between filters in a wheel.\u003c\/li\u003e\n            \u003cli\u003e\n\u003cstrong\u003eSurface Quality (60\/40):\u003c\/strong\u003e A clean, professional-grade surface finish minimizes scatter and artifacts.\u003c\/li\u003e\n        \u003c\/ul\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n    \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eMechanical Design: 2-Inch Format with 44mm Clear Aperture\u003c\/h3\u003e\n      \u003cp\u003eThe SV227 is housed in a standard 2-inch cell with M48x0.75 threads, making it compatible with virtually all modern filter wheels, filter drawers, and accessories. Its generous 44mm clear aperture provides an unvignetted field for cameras with APS-C or even larger sensors, ensuring even illumination from edge to edge. The filter features a single-thread design, intended for use within a filter holder rather than for stacking directly onto other filters or eyepieces.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003e5nm vs. Wider Bandwidths: Contrast and Signal Trade-offs\u003c\/h3\u003e\n      \u003cp\u003eChoosing a bandwidth is a critical decision in narrowband imaging. The SV227's 5nm bandpass offers a significant advantage over wider 7nm or 12nm filters, especially under light-polluted skies, by providing a darker background and higher contrast. While a narrower 3nm filter might offer even more contrast, it requires longer exposure times to achieve the same signal level. The 5nm design represents a highly effective balance, delivering excellent contrast without demanding excessive sub-exposure times, making it a practical choice for a wide range of telescopes and sky conditions.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main advantage of the SVBONY SV227's 5nm bandwidth?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe primary advantage of the \u003cstrong\u003e5nm bandwidth\u003c\/strong\u003e is significantly higher contrast compared to wider filters (like 7nm or 12nm). It does a better job of rejecting light pollution, moonlight, and natural skyglow, making faint nebula details pop against a darker background. This is especially beneficial for imagers in suburban or urban locations.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the SV227 5nm H-Alpha filter perform on the Pelican Nebula (IC 5070) from a suburban backyard?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe SV227 is ideal for this scenario. The Pelican Nebula is rich in H-alpha emissions. From a suburban backyard, the \u003cstrong\u003e5nm bandpass\u003c\/strong\u003e will effectively isolate the nebula's 656.3nm signal from city skyglow, allowing you to capture its intricate dust lanes and bright ionization fronts with much greater clarity than you could with a broadband or wider narrowband filter.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the SV227 2-inch filter a good match for a fast f\/4 Newtonian telescope?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, but with a consideration. Fast optical systems can cause a slight \"band-shift\" in narrowband filters. While the SV227's 5nm bandpass is generally robust enough for systems down to f\/4, it offers a good balance between the contrast benefits of narrowband and tolerance for faster optics. The high ≥90% transmittance also helps gather signal efficiently in these fast systems.\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 astrophotos with the SV227 filter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003e\u003cstrong\u003eOD5 blocking\u003c\/strong\u003e means the filter reduces unwanted light outside its 5nm bandpass by a factor of at least 100,000. For your images, this translates to:\n    \u003c\/p\u003e\n\u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCleaner Backgrounds:\u003c\/strong\u003e It eliminates gradients caused by light pollution or moonlight.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eTighter Stars:\u003c\/strong\u003e It prevents halos and bloating around bright stars caused by out-of-band emissions (like near-infrared).\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eHigher Contrast:\u003c\/strong\u003e By ensuring only the desired 656.3nm light reaches the sensor, the nebula signal is maximized relative to the background noise.\u003c\/li\u003e\n    \u003c\/ul\u003e\n    \n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eThe SVBONY SV227 filter has a single M48x0.75 thread. Can I stack it with other filters?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo, this filter is not designed for stacking. The \u003cstrong\u003eSingle Thread: Yes\u003c\/strong\u003e specification indicates it has threads on one side only, meant for securing it into a filter wheel or filter drawer. It does not have female threads on the opposite side to attach another filter directly to it.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 1.85mm substrate thickness of the SV227 filter parfocal with other filters?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe \u003cstrong\u003e1.85mm thickness\u003c\/strong\u003e is quite thin, which helps minimize focus shift between filters. However, achieving perfect parfocal performance across an entire set of filters from different manufacturers is rare. While the SV227 is designed to be close, you should expect to make minor focus adjustments when switching between it and other filters, especially those with different substrate thicknesses.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003ctable class=\"DAV-specifications\"\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd\u003eFilter Type\u003c\/td\u003e\n\u003ctd\u003eH-Alpha Narrowband\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\u003e656.3nm\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 Range\u003c\/td\u003e\n\u003ctd\u003e300-1000nm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eBlocking Depth\u003c\/td\u003e\n\u003ctd\u003e≥OD5\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\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\u003eThreading\u003c\/td\u003e\n\u003ctd\u003eSingle Thread\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\n\u003cli\u003e\n  \u003cul class=\"DAV-grid\"\u003e\n    \u003cli class=\"DAV-grid-item\"\u003e\n      \u003cdiv\u003e\n        \u003cp class=\"DAV-item-title\"\u003eSVBONY SV227 2\" H-Alpha 5nm Filter\u003c\/p\u003e\n        \u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/li\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":52861237133597,"sku":"SV-W9187DB","price":131.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/SVBONY-SV227-2-H-Alpha-5nm-Narrowband-CCD-Filter-for-Deep-Sky-1_ab1cee9f-5a35-4f02-889e-fbc732a5f309.jpg?v=1788883673"},{"product_id":"svbony-sv227-oiii-5nm-narrowband-filter-2in","title":"SVBONY SV227 OIII 5nm Narrowband Filter - 2\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eIsolates the Oxygen III emission line at 500.7nm\u003c\/li\u003e\n\u003cli\u003eExtremely narrow 5nm Full Width at Half Maximum (FWHM) bandpass\u003c\/li\u003e\n\u003cli\u003eAchieves ≥90% peak light transmittance at the OIII line\u003c\/li\u003e\n\u003cli\u003eStandard 2-inch format with M48x0.75 filter threads\u003c\/li\u003e\n\u003cli\u003ePrecision 1.85mm thick substrate with 1\/4λ surface parallelism\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 OIII 5nm 2-inch Telescope Filter\u003c\/h2\u003e\n\u003cp\u003eThe SVBONY SV227 OIII 5nm 2-inch filter is engineered to isolate the doubly ionized oxygen signal from planetary nebulae and supernova remnants with extreme prejudice. Its tight 5nm bandpass is centered precisely at the 500.7nm wavelength, achieving ≥90% peak transmittance to capture faint structures while suppressing overwhelming light pollution. The optical substrate is held to a 1\/4λ parallelism with a 60\/40 surface quality, ensuring the filter preserves the sharpness of your optical system across its full 44mm clear aperture.\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\u003eIsolate Nebulae with a 5nm FWHM Bandpass\u003c\/h3\u003e\n\u003cp\u003eThe core of the SV227 filter's imaging capability is its extremely narrow 5nm Full Width at Half Maximum (FWHM). This tight window, centered at 500.7nm, passes light almost exclusively from the OIII emission line, which is critical for revealing the delicate, glowing structures within planetary nebulae like the Dumbbell Nebula (M27) or the faint, expansive shells of supernova remnants like the Veil Nebula (NGC 6960).\u003c\/p\u003e\n\u003cp\u003eBy rejecting nearly all other wavelengths across its 300-1000nm blocking range, the filter dramatically increases contrast and allows you to pull faint details out from even heavily light-polluted skies. With a peak transmittance of ≥90%, the filter passes the maximum amount of critical signal to your sensor, keeping exposure times manageable for such a narrow bandpass.\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\u003e1\/4λ Substrate for Sharp Stars Across the Field\u003c\/h3\u003e\n\u003cp\u003eA filter is part of your optical train, and any imperfection can degrade the final image. The SV227 is built on a 1.85mm thick glass substrate polished to a 1\/4λ surface parallelism and a 60\/40 surface quality. This level of precision prevents the filter from introducing astigmatism or other distortions that can elongate stars, especially towards the edge of the field.\u003c\/p\u003e\n\u003cp\u003eThe 30\" parallelism specification ensures the two faces of the filter are almost perfectly parallel, minimizing any wedge effect that could cause image shift or focus problems when swapping between filters in a wheel. This attention to optical quality means your stars remain as tight and round as your telescope's optics can deliver.\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\u003e2-Inch Format with a 44mm Clear Aperture\u003c\/h3\u003e\n\u003cp\u003eDesigned for modern imaging setups, the SV227 comes in a standard 2-inch cell with M48x0.75 threads. This makes it directly compatible with most 2-inch filter wheels, filter drawers, and dedicated astronomy cameras. The filter provides a generous 44mm clear aperture, large enough to fully illuminate full-frame sensors without introducing vignetting from the filter cell itself.\u003c\/p\u003e\n\u003cp\u003eDespite its robust optical specifications, the filter is remarkably light, weighing only 12.5g. This low mass helps maintain the balance of your imaging train and reduces the strain on focuser motors and filter wheel mechanisms during operation.\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\u003e5nm vs. Wider OIII Filters: The Contrast Trade-Off\u003c\/h3\u003e\n\u003cp\u003eChoosing a narrowband filter involves a trade-off between contrast and exposure time. The SV227's 5nm bandpass represents a move towards higher contrast and better suppression of unwanted light.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSVBONY SV227 5nm Filter:\u003c\/strong\u003e Its primary advantage is maximum contrast. It darkens the sky background more effectively than wider filters, making it superior for pulling out the faintest details from emission nebulae, especially from urban or suburban locations. The trade-off is that it requires longer sub-exposure times to gather the same amount of signal as a wider filter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWider 7nm or 12nm Filters:\u003c\/strong\u003e These filters are more forgiving, allowing for shorter sub-exposures. However, they let in more skyglow and continuum emission from stars, resulting in a brighter background and slightly lower overall contrast on the nebula itself. They are often a good starting point, but the 5nm is the specialist's tool for difficult targets.\u003c\/li\u003e\n\u003c\/ul\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\"\u003eHow will the SVBONY SV227 5nm filter perform on the Veil Nebula (NGC 6960) from a Bortle 7 zone?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe SV227 is ideal for this exact scenario. The Veil Nebula is a classic OIII-rich supernova remnant, but its faint, filamentary structure is easily lost in skyglow. The tight \u003cstrong\u003e5nm bandpass\u003c\/strong\u003e will aggressively reject the Bortle 7 light pollution, dramatically increasing contrast and making the nebula's delicate wisps stand out against a dark background.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 1.85mm substrate thickness of the SV227 filter parfocal with other brands?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e1.85mm thickness\u003c\/strong\u003e is very close to the thickness of many other popular filter brands. While perfect parfocality is never guaranteed across different manufacturers, this thickness should result in minimal focus shift when used in a filter wheel alongside other modern narrowband or LRGB filters. You may need only a very small focus adjustment.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does the ≥OD5 blocking on the SV227 OIII filter mean for my images?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eOD5 blocking\u003c\/strong\u003e means the filter blocks out-of-band light by a factor of 100,000 (Optical Density 5). This is a high level of blocking that ensures light from streetlights, the moon, and unwanted wavelengths from stars does not leak through and cause halos or gradients in your final image. It's a critical specification for clean, high-contrast astrophotography.\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 OIII filter for visual observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile technically possible on very bright planetary nebulae like the Ring Nebula (M57) with a large aperture telescope, it's generally not recommended. The \u003cstrong\u003e5nm bandpass\u003c\/strong\u003e is so restrictive that it makes the view extremely dim, and most stars will disappear entirely. This filter is designed specifically for long-exposure astrophotography, not visual use.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is the 44mm clear aperture of the SV227 important?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e44mm clear aperture\u003c\/strong\u003e is larger than the diagonal of an APS-C sensor and nearly matches the diagonal of a full-frame sensor. This ensures that even with a fast optical system, the filter housing itself will not block light at the corners of your sensor, preventing vignetting and ensuring even illumination across your entire field of view.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the M48x0.75 single thread on the SV227 filter cause any issues?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this is standard. The \u003cstrong\u003eM48x0.75 single thread\u003c\/strong\u003e is on the side of the filter that threads into your camera or filter wheel. The other side is unthreaded. This design prevents you from accidentally stacking filters, which can cause internal reflections and degrade image quality. It ensures the filter is always mounted correctly in the optical train.\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\u003eOIII Narrowband\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\u003e500.7nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandwidth (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 Range\u003c\/td\u003e\n\u003ctd\u003e300-1000nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Depth\u003c\/td\u003e\n\u003ctd\u003e≥OD5\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\u003eClear Aperture\u003c\/td\u003e\n\u003ctd\u003e44mm\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\u003eThreading\u003c\/td\u003e\n\u003ctd\u003eSingle-Sided\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 Warranty Policy\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"SVBONY","offers":[{"title":"Default Title","offer_id":52861237166365,"sku":"SV-W9187DC","price":131.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/SVBONY-SV227-OIII-5nm-2-inch-Telescope-Filter-for-Nebula-Imaging-1_244e2422-e55d-42dd-bedc-ce93fe8bab7c.jpg?v=1788883686"}],"url":"https:\/\/davidastro.com\/fr\/collections\/svbony-sv227-5nm-narrowband-filters.oembed","provider":"David Astro","version":"1.0","type":"link"}