{"title":"Optolong Narrowband Filters","description":"\u003cp\u003eOptolong narrowband filters isolate single emission lines for imaging nebulae with a monochrome astronomy camera, even from bright city skies. The range covers H-alpha, OIII and SII filters in 3nm and in 6.5nm or 7nm bandwidths, plus sets: Ha, OIII and SII 3nm, Ha 7nm with OIII and SII 6.5nm, and LRGB sets with H-alpha or with all three narrowband lines.\u003c\/p\u003e\u003cp\u003eThe 3nm filters give the highest contrast, while 6.5nm and 7nm versions are more forgiving of fast optics.\u003c\/p\u003e","products":[{"product_id":"optolong-lrgb-ha-oiii-sii-filter-set","title":"Optolong LRGB, Ha, OIII \u0026 SII Filter Set","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eComplete 7-filter set for monochrome astrophotography\u003c\/li\u003e\n\u003cli\u003eIncludes Luminance, Red, Green, and Blue broadband filters\u003c\/li\u003e\n\u003cli\u003eIncludes 3nm Hydrogen-alpha, Oxygen-III, and Sulphur-II narrowband filters\u003c\/li\u003e\n\u003cli\u003eLRGB set features a gap to block 589nm sodium light pollution\u003c\/li\u003e\n\u003cli\u003eEnables both natural color LRGB and Hubble Palette SHO imaging\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\u003eOptolong LRGB, Ha, OIII \u0026amp; SII Filter Set\u003c\/h2\u003e\n\u003cp\u003eThe Optolong LRGB, Ha, OIII \u0026amp; SII Filter Set provides a complete 7-filter solution for advanced monochrome imaging. This comprehensive kit combines a high-contrast LRGB filter set for natural-color broadband targets with a trio of 3nm narrowband filters for isolating emission nebulae. The LRGB set is engineered with a specific gap between the green and red filters to block the primary sodium light pollution line at 589nm, while the 3nm SHO filters target the critical 656nm H-alpha and 500nm OIII emission lines for maximum signal and contrast.\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\u003eLRGB + 3nm SHO: The Complete 7-Filter Monochrome Solution\u003c\/h3\u003e\n\u003cp\u003eThis 7-filter set equips your monochrome camera for virtually any deep-sky object. You can capture galaxies and star clusters in true-to-life color with the LRGB filters, then switch to the 3nm narrowband filters to capture the faint, intricate structures of emission and planetary nebulae. By including both sets, Optolong eliminates the need to build a filter collection piece by piece, providing a unified system for both broadband and narrowband workflows.\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\u003eLRGB Imaging: Natural Color Balance with a 589nm Sodium Cutoff\u003c\/h3\u003e\n\u003cp\u003eThe Optolong LRGB filters are designed for maximum color separation and contrast. The transmission curves feature extremely high gradients to clearly differentiate color channels, while a carefully placed gap between the green and red filters blocks the prominent 589nm sodium light pollution line. This targeted rejection significantly improves color balance and makes post-processing more straightforward. Furthermore, OIII emission is allowed to pass through both the blue and green filters, ensuring high efficiency when capturing planetary nebulae in LRGB and preserving their natural teal coloration.\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\u003e3nm SHO Filters: Isolating Ha, OIII, and SII for the Hubble Palette\u003c\/h3\u003e\n\u003cp\u003eFor the highest possible contrast on emission nebulae, the 3nm SHO (Sulphur-II, Hydrogen-alpha, Oxygen-III) filters isolate the specific wavelengths of ionized gas while rejecting nearly all other light. This extreme narrow bandpass darkens the sky background, suppresses moonlight and artificial light pollution, and makes faint nebulosity stand out. By assigning the data from the SII, Ha, and OIII filters to the red, green, and blue channels in processing, you can create the iconic, high-contrast images made famous by the Hubble Space Telescope.\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\u003e656nm Ha \u0026amp; 500nm OIII: Capturing the Universe's Primary Emission Lines\u003c\/h3\u003e\n\u003cp\u003eThe 3nm H-alpha filter is centered at 656nm, capturing the dominant wavelength emitted by vast star-forming regions across the Milky Way. The 3nm OIII filter is centered at 500nm to capture the strong blue-green light from doubly ionized oxygen, characteristic of planetary nebulae and supernova remnants. Used together, these two filters can produce stunning bicolor images that reveal incredible structural detail while maintaining a natural, scientifically relevant color palette.\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 advantage of this Optolong 7-filter set?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary advantage is its completeness. This single set provides all the necessary filters for the two main types of monochrome deep-sky imaging: \u003cstrong\u003eLRGB\u003c\/strong\u003e for broadband targets like galaxies and star clusters, and \u003cstrong\u003e3nm SHO narrowband\u003c\/strong\u003e for emission nebulae. This allows you to tackle any object without needing to purchase additional filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is the 3nm bandpass on the Optolong SHO filters important?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA 3nm bandpass is extremely narrow, meaning it only allows a tiny sliver of the light spectrum to pass through to the sensor. This provides exceptional rejection of light pollution from city lights, moonlight, and natural skyglow. The result is a much darker background and significantly higher contrast on faint nebulae compared to wider 6nm or 7nm filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow would I use this Optolong filter set to image the Orion Nebula (M42)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eM42 is a complex object with both bright stars and extensive nebulosity. A great approach is a hybrid one:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eUse the \u003cstrong\u003eH-alpha and OIII filters\u003c\/strong\u003e to capture long exposures of the faint, sprawling nebulosity with high contrast.\u003c\/li\u003e\n\u003cli\u003eUse the \u003cstrong\u003eLRGB filters\u003c\/strong\u003e to capture a series of shorter exposures to resolve the bright Trapezium star cluster at the core without overexposing it.\u003c\/li\u003e\n\u003cli\u003eIn post-processing, you can combine the data from all filters to create a final image with a full dynamic range and rich detail.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhich filters from the Optolong set are best for the Andromeda Galaxy (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Andromeda Galaxy is a broadband target, meaning it shines across the visible spectrum like a star cluster. For M31, you would primarily use the \u003cstrong\u003eLRGB filters\u003c\/strong\u003e to capture its bright core, spiral arms, and dust lanes in natural color. You can also use the \u003cstrong\u003eH-alpha filter\u003c\/strong\u003e to take very long exposures, which will reveal the small, pinkish star-forming regions (HII regions) embedded within its spiral arms.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the \"Hubble Palette\" and how does this Optolong set enable it?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Hubble Palette is a false-color imaging technique used to differentiate structures in emission nebulae. It involves mapping data from the three narrowband filters to the RGB channels of a color image:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSulphur-II (SII)\u003c\/strong\u003e data is mapped to the \u003cstrong\u003eRed\u003c\/strong\u003e channel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHydrogen-alpha (Ha)\u003c\/strong\u003e data is mapped to the \u003cstrong\u003eGreen\u003c\/strong\u003e channel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOxygen-III (OIII)\u003c\/strong\u003e data is mapped to the \u003cstrong\u003eBlue\u003c\/strong\u003e channel.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThis Optolong set includes all three required SII, Ha, and OIII filters, allowing you to create these vibrant and detailed images.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does the gap between the green and red Optolong LRGB filters do?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe gap is a design feature for light pollution suppression. It is specifically placed to block the transmission of light around the \u003cstrong\u003e589nm\u003c\/strong\u003e wavelength. This is the primary emission line of sodium-vapor streetlights, a major source of urban skyglow. By blocking this line, the filters improve color separation and produce a cleaner image from suburban or city locations.\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 Count\u003c\/td\u003e\n\u003ctd\u003e7 (Luminance, Red, Green, Blue, Ha, OIII, SII)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNarrowband Bandpass\u003c\/td\u003e\n\u003ctd\u003e3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-Alpha Center Wavelength\u003c\/td\u003e\n\u003ctd\u003e656nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOIII Center Wavelength\u003c\/td\u003e\n\u003ctd\u003e500nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLight Pollution Rejection\u003c\/td\u003e\n\u003ctd\u003eNotch at 589nm (Sodium Line)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Formats\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 36mm Round Unmounted, 2\" Mounted\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\"\u003eLuminance (L) Filter\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\"\u003eRed (R) Filter\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\"\u003eGreen (G) Filter\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\"\u003eBlue (B) Filter\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\"\u003e3nm H-Alpha (Ha) Filter\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\"\u003e3nm Oxygen-III (OIII) Filter\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\"\u003e3nm Sulphur-II (SII) 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\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":44967911293213,"sku":"OPT-LRGBSHO-1.25","price":931.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":44967911358749,"sku":"OPT-LRGBSHO-RD36","price":1085.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":44967911391517,"sku":"OPT-LRGBSHO-2","price":1413.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Optolong-LRGB-Ha-OIII-SII-Filter-Set__74483.1626291721.1280.1280.jpg?v=1684346905"},{"product_id":"optolong-h-alpha-3nm-filter","title":"Optolong H-alpha 3nm Narrowband Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e3nm Bandpass at 656nm Wavelength\u003c\/li\u003e\n\u003cli\u003eMaximizes Contrast for Emission Nebulae\u003c\/li\u003e\n\u003cli\u003eExtreme Rejection of Light Pollution and Skyglow\u003c\/li\u003e\n\u003cli\u003eIon-Assisted, Anti-Reflection Coatings\u003c\/li\u003e\n\u003cli\u003eThermally Stable Central Wavelength (CWL)\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\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\u003eOptolong H-alpha 3nm Narrowband Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong H-alpha 3nm Narrowband Filter isolates the critical 656nm hydrogen-alpha emission line, providing the highest possible contrast for emission nebulae. Its extremely tight 3nm bandpass aggressively blocks light pollution from sources like mercury and sodium vapor lamps, as well as natural skyglow, revealing faint structural details that wider filters miss.\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\u003eA 3nm Bandpass: Isolating the H-Alpha Signal at 656nm\u003c\/h3\u003e\n\u003cp\u003eThis filter is engineered for imagers seeking maximum signal-to-noise ratio from emission targets. The 3nm bandpass centered at 656nm transmits only the light from ionized hydrogen, creating a near-black sky background even from bright, urban locations. This extreme selectivity is the key to capturing the delicate, filamentary details in targets like the Veil Nebula (NGC 6960) or the faint outer regions of the Rosette Nebula (NGC 2237).\u003c\/p\u003e\n\u003cp\u003eFor astrophotographers building Hubble Palette (SHO) images with monochrome cameras, the 3nm H-alpha filter provides the foundational luminance layer with exceptional depth and contrast. It is the definitive choice for separating faint H-alpha structures from overwhelming light pollution.\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\u003eAdvanced Coatings for 3nm Filters: Thermal Stability and Halo Suppression\u003c\/h3\u003e\n\u003cp\u003eOptolong utilizes ion-assisted deposition coating technology to ensure durability, scratch resistance, and optical stability. This process produces uniform, multi-layer coatings that are critical for maintaining the filter's precise 3nm central wavelength (CWL) as ambient temperatures change during an imaging session. This stability prevents focus shift and ensures consistent data collection throughout the night.\u003c\/p\u003e\n\u003cp\u003eThese advanced coatings are also optimized to suppress halos around bright stars. By minimizing internal reflections, the 3nm H-alpha filter delivers clean star profiles, preserving the faint nebulosity that often surrounds prominent stars like Alnitak in the Horsehead Nebula (Barnard 33) region.\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\u003eOptolong 3nm vs. 7nm H-Alpha: Choosing the Right Bandpass\u003c\/h3\u003e\n\u003cp\u003eThe choice between a 3nm and a 7nm filter depends on your imaging goals, location, and equipment. While both are excellent narrowband filters, they serve different primary purposes.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptolong 7nm H-Alpha:\u003c\/strong\u003e The 7nm filter gathers light more than twice as fast, allowing for shorter sub-exposures. This makes it more forgiving of minor tracking errors and a better choice for portable setups or when imaging time is limited. It provides a significant contrast boost over broadband filters and is an excellent all-around narrowband option.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptolong 3nm H-Alpha:\u003c\/strong\u003e The 3nm filter is the specialist's tool for ultimate contrast. It provides superior rejection of light pollution, moonlight, and skyglow. The trade-off is that it requires longer exposures and demands precise guiding and focus. For imagers in Bortle 7+ skies or those chasing the absolute faintest details, the 3nm filter's performance is unmatched.\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\"\u003eWhy choose the Optolong 3nm H-alpha filter over a 7nm version?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe 3nm bandpass offers the highest possible contrast and light pollution rejection, making it ideal for revealing extremely faint nebula details from urban or suburban skies. The trade-off is that it requires longer exposure times and more precise guiding compared to a 7nm filter, which gathers light faster.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong 3nm H-alpha filter perform under heavily light-polluted skies?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt excels in these conditions. The extremely narrow 3nm window passes only the H-alpha emission line at 656nm, while aggressively blocking broadband light from city lights, moonlight, and natural skyglow. This creates a near-black sky background, dramatically improving the signal-to-noise ratio of your images.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong 3nm H-alpha filter suitable for one-shot color cameras?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile designed for \u003cstrong\u003emonochrome cameras\u003c\/strong\u003e, it can be used with one-shot color (OSC) cameras, especially modified ones with greater red sensitivity. However, since it only passes light to the red pixels on the sensor, you will get a monochrome image that requires significant processing. For OSC cameras, a multi-bandpass filter is often a more efficient choice.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Optolong 3nm H-alpha filter help capture the Veil Nebula (NGC 6960) from my backyard?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Veil Nebula is rich in Hydrogen-alpha, but its delicate, filamentary structure can be washed out by skyglow. The Optolong 3nm filter will isolate this Ha signal with extreme precision, allowing you to capture fine, high-contrast details in the Witch's Broom and surrounding nebulosity, even with a bright moon or city lights.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat exposure times should I expect for the North American Nebula (NGC 7000) with the Optolong 3nm H-alpha filter on an f\/5 refractor?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWith a fast f\/5 system and a modern monochrome CMOS camera, typical sub-exposure times for a bright target like the North American Nebula would range from \u003cstrong\u003e300 to 600 seconds (5 to 10 minutes)\u003c\/strong\u003e. The exact time depends on your camera's sensitivity and your desired signal-to-noise ratio, but the 3nm bandpass will require longer exposures than a wider filter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo I need to refocus when switching between Optolong's 3nm SHO filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eOptolong's 3nm filters are manufactured with high precision to be nearly parfocal. While minor focus adjustments may be needed due to temperature changes or optical tolerances, you should not require major refocusing when switching between the H-alpha, OIII, and SII 3nm filters in the same set.\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\u003eNarrowband Interference Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandpass\u003c\/td\u003e\n\u003ctd\u003e3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCentral Wavelength (CWL)\u003c\/td\u003e\n\u003ctd\u003e656nm (H-alpha)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating Technology\u003c\/td\u003e\n\u003ctd\u003eIon-assisted deposition, multi-layer anti-reflection\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Formats\u003c\/td\u003e\n\u003ctd\u003e36mm Round Unmounted, 2\" Mounted\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\"\u003eOptolong H-alpha 3nm Narrowband Filter\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\"\u003eProtective Case\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\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"36mm Round Unmounted","offer_id":50923151556893,"sku":"OPT-14103","price":474.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":50923151589661,"sku":"OPT-14102","price":586.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-H-alpha-3nm-Filter-1.jpg?v=1770478823"},{"product_id":"optolong-sii-3nm-narrowband-filter","title":"Optolong SII 3nm Narrowband Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eIsolates the Sulfur-II (SII) emission line for astrophotography\u003c\/li\u003e\n\u003cli\u003eExtremely narrow 3nm bandpass for maximum contrast\u003c\/li\u003e\n\u003cli\u003eDrastically reduces skyglow and common light pollution sources\u003c\/li\u003e\n\u003cli\u003eAdvanced ion-assisted anti-reflection coatings\u003c\/li\u003e\n\u003cli\u003eAvailable in 2\" mounted or 36mm unmounted formats\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\u003eOptolong SII 3nm Narrowband Filter\u003c\/h2\u003e\n      \u003cp\u003eThe Optolong SII 3nm Narrowband Filter isolates the critical Sulfur-II emission line with an extremely tight 3nm bandpass. This precision dramatically increases contrast against even severe light pollution, darkening the sky background to reveal the faintest structural details in emission nebulae that wider filters cannot resolve. By passing only a 3nm sliver of the spectrum, the filter effectively eliminates interference from mercury vapor, sodium vapor, and natural skyglow.\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\u003eThe 3nm Bandpass: Isolate Signal and Suppress Light Pollution\u003c\/h3\u003e\n      \u003cp\u003eAn ultra-narrow 3nm bandpass is the key to pulling faint nebula signal out of a bright sky. Compared to wider 7nm or 12nm filters, the 3nm design provides a significant boost in signal-to-noise ratio. This allows for longer sub-exposures from urban or suburban locations, capturing deep data that would otherwise be lost in the glare.\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\u003eThe \"S\" in SHO: Building a 3nm Hubble Palette\u003c\/h3\u003e\n      \u003cp\u003eThe SII 3nm filter is an essential component for creating false-color Hubble Palette images. It captures the light emitted by ionized sulfur, which is typically mapped to the red channel in an SHO (SII, H-alpha, OIII) composite. This data reveals unique structures within star-forming regions and supernova remnants, adding depth, dimension, and scientific context to your 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\u003eIon-Assisted Coatings for 3nm Thermal Stability\u003c\/h3\u003e\n      \u003cp\u003eMaintaining a precise 3nm bandpass requires advanced coating technology. Optolong utilizes an ion-assisted deposition process to create hard, scratch-resistant coatings that are exceptionally stable. This ensures the filter's central wavelength does not drift with temperature changes during an imaging session, preventing signal loss and guaranteeing consistent results from dusk until dawn.\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 benefit of the Optolong SII 3nm filter over a wider 7nm version?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe primary benefit of the \u003cstrong\u003e3nm bandpass\u003c\/strong\u003e is significantly higher contrast and better light pollution suppression. By blocking more of the unwanted skyglow, the 3nm filter produces a darker background and makes faint nebula details stand out more clearly, especially from urban or suburban locations.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong SII 3nm filter perform on the Soul Nebula (IC 1848)?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eFor a target like the Soul Nebula (IC 1848), the Optolong SII 3nm filter is excellent for isolating the delicate structures traced by ionized sulfur. This signal is often fainter than the dominant H-alpha, and the high contrast of the 3nm filter is crucial for capturing the wispy details and separating them from the background starfield, forming the basis of the red channel in a Hubble Palette image.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong SII 3nm filter with a color camera?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eWhile designed for monochrome cameras, you can use the Optolong SII 3nm filter with a one-shot-color (OSC) camera. However, because the camera's Bayer matrix only allows a fraction of the pixels (the red ones) to detect the SII signal, the resulting image will have lower resolution and require much longer total integration time compared to using a monochrome sensor.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong SII 3nm filter suitable for imaging from a Bortle 8 zone?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, absolutely. The Optolong SII 3nm filter is specifically designed for conditions like a Bortle 8 or 9 sky. Its extremely narrow 3nm bandpass aggressively rejects common sources of artificial light pollution, allowing you to capture clean narrowband data even from the middle of a city.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat role does the Optolong SII 3nm filter data play in a final Hubble Palette image?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eIn the standard SHO Hubble Palette, data from the Optolong SII 3nm filter is assigned to the \u003cstrong\u003eRed\u003c\/strong\u003e channel. H-alpha data is assigned to Green, and OIII data is assigned to Blue. The SII signal often highlights the shock fronts and outer edges of nebulae, providing the warm golden and reddish hues that define the iconic Hubble look.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the central wavelength of the Optolong SII 3nm filter shift with temperature?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo. The Optolong SII 3nm filter is manufactured with an ion-assisted deposition coating process. This creates a very stable filter that ensures the central wavelength (CWL) does not deviate due to temperature changes during your imaging session, leading to more consistent data collection.\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\u003eNarrowband\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eEmission Line\u003c\/td\u003e\n\u003ctd\u003eSulfur-II (SII)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eBandpass\u003c\/td\u003e\n\u003ctd\u003e3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eAvailable Formats\u003c\/td\u003e\n\u003ctd\u003e2\" Mounted, 36mm Round Unmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eCoating Technology\u003c\/td\u003e\n\u003ctd\u003eMulti-layer, anti-reflection with Ion-assisted deposition\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\"\u003eOptolong SII 3nm Narrowband Filter (in selected size)\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\"\u003eProtective Case\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\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"2\" Mounted","offer_id":52941908181277,"sku":"OPT-14202","price":587.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":52941908214045,"sku":"OPT-14203","price":475.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-SII-3nm-Narrowband-Filter-1_f02f4e7c-603a-4030-8e53-634290e38f82.jpg?v=1789592304"},{"product_id":"optolong-oiii-3nm-narrowband-filter","title":"Optolong OIII 3nm Narrowband Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e3nm Spectral Bandpass\u003c\/li\u003e\n\u003cli\u003e500nm Central Wavelength (OIII)\u003c\/li\u003e\n\u003cli\u003eIon-Assisted Multi-Layer Coatings\u003c\/li\u003e\n\u003cli\u003eOptimized for Monochrome Cameras\u003c\/li\u003e\n\u003cli\u003eAvailable in 2\" Mounted or 36mm Unmounted\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\u003eOptolong OIII 3nm Narrowband Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong OIII 3nm Narrowband Filter isolates the critical doubly-ionized oxygen emission lines at 495.9nm and 500.7nm with an extremely tight 3nm bandpass centered at 500nm. This precision allows you to capture maximum-contrast images of planetary nebulae and supernova remnants by aggressively rejecting light pollution and skyglow, revealing faint structural details even from urban locations or under a bright moon.\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 3nm Bandpass Advantage: Isolating the 500nm OIII Signal\u003c\/h3\u003e\n\u003cp\u003eBy restricting transmission to a mere 3nm window, this filter dramatically increases the signal-to-noise ratio of your images. It effectively blocks out interfering wavelengths from streetlights and atmospheric glow, darkening the sky background and making faint, blue-green OIII structures pop. This is the key to resolving the delicate shells of the Dumbbell Nebula (M27) or the intricate filaments of the Veil Nebula (NGC 6960).\u003c\/p\u003e\n\u003cp\u003eWhile primarily designed for monochrome cameras, this filter can be used with modified color cameras for extreme light pollution rejection. When combined with H-alpha and SII filters, the OIII 3nm filter is an essential component for creating stunning Hubble Palette (SHO) composites.\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\u003eAdvanced Coatings: Ion-Assisted Deposition for Durability and Halo Control\u003c\/h3\u003e\n\u003cp\u003eOptolong utilizes an advanced ion-assisted deposition coating process to ensure the filter's transmission characteristics are precise and uniform. This technology produces hard, scratch-resistant surfaces and guarantees the central wavelength (CWL) will not shift due to temperature changes during your imaging session.\u003c\/p\u003e\n\u003cp\u003eA significant focus of the 3nm design was minimizing the halos that can appear around bright stars in narrowband images. Through optimized coating techniques, this filter exhibits significantly improved halo performance compared to previous generations, ensuring that bright stars like Sadr in Cygnus don't overwhelm the surrounding nebulosity.\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\u003eOptolong 3nm vs. 7nm OIII: When to Choose the Tighter Bandpass\u003c\/h3\u003e\n\u003cp\u003eChoosing between a 3nm and a 7nm filter involves a direct trade-off between contrast and exposure time. A wider 7nm filter is more forgiving, requires shorter sub-exposures, and is an excellent choice for darker skies or faster optical systems.\u003c\/p\u003e\n\u003cp\u003eThe 3nm filter is the superior tool when ultimate contrast is the goal. It provides a darker background and isolates the nebula signal more effectively, making it the ideal choice for imaging from heavily light-polluted areas or during bright moon phases. This higher contrast comes at the cost of requiring longer exposure times to achieve the same signal level, demanding accurate guiding and a stable setup.\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 advantage of the Optolong OIII 3nm filter over a 7nm version?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary advantage is \u003cstrong\u003ehigher contrast\u003c\/strong\u003e. The tighter 3nm bandpass more aggressively rejects background light from skyglow and artificial sources. This makes it superior for pulling out faint nebulosity from light-polluted skies or when imaging during a bright moon.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Optolong OIII 3nm filter help me image the Cygnus Loop (Veil Nebula) from my Bortle 8 backyard?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Veil Nebula is a classic OIII target. From a Bortle 8 location, the skyglow would normally overwhelm the nebula's faint, filamentary structure. The Optolong OIII 3nm filter blocks this light pollution, isolating the specific 500nm light from the nebula and dramatically increasing its visibility against a dark background, allowing you to capture details that would otherwise be impossible.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong OIII 3nm filter with a color camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile designed for monochrome sensors, you can use it with a one-shot-color (OSC) or modified DSLR camera. Since the filter only passes a narrow band of blue-green light, your resulting image will be monochrome. This is an effective strategy for extreme light pollution suppression with a color camera, but a dedicated monochrome camera will always provide a stronger signal.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat types of celestial objects are best suited for the Optolong OIII 3nm filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis filter excels on emission nebulae that are rich in doubly-ionized oxygen. Prime targets include:\n\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePlanetary Nebulae:\u003c\/strong\u003e The Dumbbell Nebula (M27), the Ring Nebula (M57), and the Helix Nebula (NGC 7293).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSupernova Remnants:\u003c\/strong\u003e The entire Veil Nebula complex (NGC 6960, 6992, 6995) and the Crab Nebula (M1).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSome Star-Forming Regions:\u003c\/strong\u003e Parts of the Orion Nebula (M42) and the Lagoon Nebula (M8) have significant OIII emission.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is halo control important for the Optolong OIII 3nm filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNarrowband filters can sometimes create faint rings, or halos, around very bright stars due to internal reflections within the filter glass. The Optolong OIII 3nm filter uses an advanced coating process specifically designed to minimize these artifacts. This ensures that when you're imaging a target near a bright star, the star remains a clean point of light without a distracting halo that could obscure faint, nearby details.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the Optolong OIII 3nm filter require longer exposures?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. Because the 3nm bandpass is so restrictive, it passes less total light than a wider 7nm or 12nm filter. To compensate and build up enough signal from the nebula, you will need to use longer sub-exposure times. This makes good polar alignment and accurate autoguiding essential for sharp results.\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\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e2\" Mounted, 36mm Round Unmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandwidth (FWHM)\u003c\/td\u003e\n\u003ctd\u003e3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCentral Wavelength (CWL)\u003c\/td\u003e\n\u003ctd\u003e500nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission Lines\u003c\/td\u003e\n\u003ctd\u003eOIII (495.9nm and 500.7nm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating Technology\u003c\/td\u003e\n\u003ctd\u003eIon-Assisted Multi-layer Deposition\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Use\u003c\/td\u003e\n\u003ctd\u003eMonochrome CCD\/CMOS Cameras\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\"\u003eOptolong OIII 3nm Filter\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\"\u003eProtective Case\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\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"2\" Mounted","offer_id":52941909426461,"sku":"OPT-14302","price":587.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":52941909459229,"sku":"OPT-14303","price":475.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-OIII-3nm-Narrowband-Filter-1_a112b100-d463-447e-8461-e104641642f2.jpg?v=1789592313"},{"product_id":"optolong-sho-3nm-narrowband-filter-kit-3-pcs","title":"Optolong Ha, OIII \u0026 SII 3nm Narrowband Filter Set","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eComplete SHO set includes H-alpha, OIII, and SII filters\u003c\/li\u003e\n\u003cli\u003eUltra-narrow 3nm bandpass for maximum contrast\u003c\/li\u003e\n\u003cli\u003eIsolates 656nm Ha and 500nm OIII emission lines\u003c\/li\u003e\n\u003cli\u003eAdvanced coatings for halo suppression and durability\u003c\/li\u003e\n\u003cli\u003eIdeal for imaging in heavily light-polluted or moonlit skies\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\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\u003eOptolong Ha, OIII \u0026amp; SII 3nm Narrowband Filter Set\u003c\/h2\u003e\n\u003cp\u003eThe Optolong Ha, OIII \u0026amp; SII 3nm Narrowband Filter Set provides the essential tools for creating high-contrast Hubble Palette images from light-polluted locations. This three-filter kit isolates the most critical emission lines in deep-sky objects with an extremely narrow 3nm bandpass, targeting H-alpha at 656nm and OIII at 500nm. By aggressively rejecting skyglow, moonlight, and artificial light sources, this SHO set delivers a near-black sky background, making faint nebular structures visible with striking clarity.\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\u003e3nm Bandpass: Isolate Emission Lines with Extreme Contrast\u003c\/h3\u003e\n\u003cp\u003eThe core of this filter set's power is its ultra-narrow 3nm full width at half maximum (FWHM). This level of precision allows only the light from specific ionized gases to reach your monochrome sensor, dramatically increasing the signal-to-noise ratio. The H-alpha filter captures the 656nm line characteristic of hydrogen, while the OIII filter isolates the dual 495.9nm and 500.7nm lines from doubly ionized oxygen, revealing the intricate structures within planetary nebulae and supernova remnants.\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\u003eAdvanced Coatings for Durability and Halo Suppression\u003c\/h3\u003e\n\u003cp\u003eOptolong utilizes an ion-assisted deposition coating process to ensure these filters are durable, scratch-resistant, and optically stable. This advanced manufacturing method maintains a consistent central wavelength that does not shift with temperature changes during an imaging session. Special attention has been paid to the OIII filter, which features an optimized coating design to significantly reduce the halos and internal reflections around bright stars that can compromise narrowband images.\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\u003eMastering the Hubble Palette: Building SHO Images\u003c\/h3\u003e\n\u003cp\u003eThis filter set is designed for creating false-color \"Hubble Palette\" images, where data from each filter is mapped to a specific color channel. By assigning the Sulphur-II (SII) data to red, Hydrogen-alpha (Ha) to green, and Oxygen-III (OIII) to blue (the SHO combination), you gain immense creative control over the final image. This technique is responsible for the iconic, high-impact astrophotography seen from the Hubble Space Telescope and allows you to highlight specific structures within a nebula based on its chemical composition.\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\u003e3nm vs. 7nm Filters: Choosing the Right Bandwidth\u003c\/h3\u003e\n\u003cp\u003eWhile wider 7nm filters gather light more quickly, allowing for shorter individual exposures, they are more susceptible to light pollution and moonlight. The primary advantage of the Optolong 3nm filter set is its superior rejection of unwanted light, which is a decisive factor in urban or suburban skies.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eContrast:\u003c\/strong\u003e The 3nm bandpass delivers a significantly darker sky background and higher contrast on emission targets, making it the better choice for revealing the faintest details.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExposure Time:\u003c\/strong\u003e The narrower bandpass requires longer total integration time to achieve the same signal level as a 7nm filter. However, the resulting data is often cleaner and requires less aggressive processing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStar Control:\u003c\/strong\u003e The 3nm filters pass less continuum light from stars, resulting in smaller, tighter stars in the final image, which further enhances the visibility of the nebula itself.\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\"\u003eWhat is the main advantage of the Optolong 3nm SHO filter set over wider filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe main advantage is \u003cstrong\u003econtrast\u003c\/strong\u003e. The ultra-narrow 3nm bandpass is extremely effective at blocking out light pollution, skyglow, and moonlight. This results in a much darker background and allows faint details in emission nebulae to stand out more clearly, which is especially critical for imaging from urban or suburban locations.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong 3nm SHO set perform under a full moon or in Bortle 8\/9 skies?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis set excels in such conditions. Narrowband imaging is the preferred technique for challenging skies, and a 3nm bandpass is the most aggressive tool for the job. While a bright moon will still have some impact, these filters allow you to continue imaging targets like the North American Nebula (NGC 7000) even when broadband LRGB imaging would be impossible.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong 3nm filters with a color camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile designed for monochrome cameras, you can use them with a color camera, but it's inefficient. A color camera's Bayer matrix blocks roughly two-thirds of the incoming light for any given filter. For best results and to fully leverage the power of the 3nm bandpass, a \u003cstrong\u003emonochrome astronomy camera\u003c\/strong\u003e is strongly recommended.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is the OIII filter in the Optolong 3nm set specifically optimized for halo reduction?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eOIII filters are historically prone to producing halos or rings around very bright stars due to internal reflections within the filter glass. Optolong has applied its experience and advanced coating technologies to the 3nm OIII filter to minimize these artifacts, ensuring cleaner data, especially on targets within star-rich regions like the Cygnus constellation.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of objects are best suited for imaging with the Optolong 3nm SHO set, like the Cygnus Loop (NGC 6960)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis filter set is ideal for all types of emission nebulae. For a target like the Veil Nebula (Cygnus Loop), the results are spectacular. The \u003cstrong\u003eH-alpha\u003c\/strong\u003e filter will reveal the broad, rope-like hydrogen filaments, while the \u003cstrong\u003eOIII\u003c\/strong\u003e filter will isolate the delicate, blue-green shock fronts, which are extremely bright in oxygen. The SII provides additional structural detail for a full Hubble Palette composition.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I combine data from the Optolong Ha, OIII, and SII filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIn post-processing software like PixInsight or Photoshop, you combine the three monochrome images into a single color image. The most common method is the \u003cstrong\u003eHubble Palette (SHO)\u003c\/strong\u003e:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eAssign the \u003cstrong\u003eSII\u003c\/strong\u003e image to the Red channel.\u003c\/li\u003e\n\u003cli\u003eAssign the \u003cstrong\u003eH-alpha\u003c\/strong\u003e image to the Green channel.\u003c\/li\u003e\n\u003cli\u003eAssign the \u003cstrong\u003eOIII\u003c\/strong\u003e image to the Blue channel.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThis creates the classic gold-and-blue Hubble look, which you can then adjust for color balance and aesthetics.\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\u003eNarrowband Interference Filter Set\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eIncluded Filters\u003c\/td\u003e\n\u003ctd\u003eH-alpha, Oxygen III, Sulphur II\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandpass (FWHM)\u003c\/td\u003e\n\u003ctd\u003e3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCentral Wavelength (H-Alpha)\u003c\/td\u003e\n\u003ctd\u003e656nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCentral Wavelength (OIII)\u003c\/td\u003e\n\u003ctd\u003e500nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoatings\u003c\/td\u003e\n\u003ctd\u003eMulti-layer, Anti-Reflection, Ion-Assisted Deposition\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eOptical Glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e2\" Mounted, 36mm Round Unmounted\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\"\u003eOptolong H-alpha 3nm Filter\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\"\u003eOptolong OIII 3nm Filter\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\"\u003eOptolong SII 3nm Filter\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\"\u003eProtective Storage Case\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\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"2\" Mounted","offer_id":52941910901021,"sku":"OPT-SHO3NM-2","price":1679.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":52941910933789,"sku":"OPT-SHO3NM-RD36","price":1344.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-2021-NEW-Optolong-SHO-3nm-narrowband-filters-kit-1_af14908b-fe74-4be0-a7b8-3d92151a6b1b.jpg?v=1789592322"},{"product_id":"optolong-h-alpha-7nm-narrowband-filter","title":"Optolong H-Alpha 7nm Narrowband Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eIsolates the 656nm Hydrogen-alpha emission line\u003c\/li\u003e\n\u003cli\u003e7nm bandpass for maximum contrast\u003c\/li\u003e\n\u003cli\u003eBlocks mercury vapor, sodium vapor, and natural skyglow\u003c\/li\u003e\n\u003cli\u003eIdeal for SHO \"Hubble Palette\" and LRGB+Ha imaging\u003c\/li\u003e\n\u003cli\u003eIon-assisted multi-layer coatings for durability\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\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\u003eOptolong H-Alpha 7nm Narrowband Filter\u003c\/h2\u003e\n      \u003cp\u003eThe Optolong H-Alpha 7nm Narrowband Filter is an essential tool for deep-sky astrophotography, designed to isolate the hydrogen-alpha emission line at a 656nm wavelength. By restricting the bandwidth to just 7nm, this filter dramatically increases the contrast between emission nebulae and the background sky. It achieves this by aggressively blocking common sources of light pollution, including mercury and sodium vapor lights, as well as the natural skyglow caused by atmospheric oxygen emission.\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\u003e7nm Bandpass at 656nm: The Key to High-Contrast Nebula Imaging\u003c\/h3\u003e\n      \u003cp\u003eThe core of this filter's design is its extremely narrow 7nm bandpass centered on the 656nm H-alpha line. This precision allows you to capture the faint, intricate structures within emission nebulae like the Rosette Nebula (Caldwell 49) or the Pillars of Creation in the Eagle Nebula (M16), even under the glare of a full moon or from a light-polluted suburban backyard. The filter doesn't make the nebula brighter; it darkens the sky background so severely that the nebula's signal stands out in sharp relief, revealing details that would otherwise be completely lost.\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\u003eSHO \u0026amp; LRGB+Ha: Unlocking 2 Advanced Astrophotography Workflows\u003c\/h3\u003e\n      \u003cp\u003eThe H-Alpha 7nm filter is a cornerstone for two primary advanced imaging techniques. For monochrome camera users, it serves as the \"S\" (Sulfur-II), \"H\" (Hydrogen-alpha), and \"O\" (Oxygen-III) foundation for creating stunning \"Hubble Palette\" images. This technique allows you to continue imaging productively even when the moon is out, turning potential downtime into valuable data collection.\u003c\/p\u003e\n      \u003cp\u003eIt's also the first and most critical narrowband addition for imagers using a standard LRGB filter set. By capturing a separate H-alpha channel and blending it with your RGB data, you can dramatically enhance the structural detail and contrast of red nebulae while maintaining a natural star field color, adding a professional touch to your final images.\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\u003eIon-Assisted Coatings: Ensuring 0 CWL Deviation From Temperature Shifts\u003c\/h3\u003e\n      \u003cp\u003eOptolong utilizes an advanced ion-assisted deposition coating process to ensure the filter is both durable and optically stable. This technology produces a hard, scratch-resistant surface that stands up to regular cleaning and handling in the field. Critically, it also ensures the central wavelength (CWL) does not deviate with temperature changes during an imaging session, preventing your signal from drifting out of the narrow 7nm bandpass and maintaining consistent results from dusk till dawn.\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 purpose of the Optolong H-Alpha 7nm filter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe Optolong H-Alpha 7nm filter is designed for deep-sky astrophotography with monochrome or color cameras. Its primary function is to isolate the \u003cstrong\u003e656nm hydrogen-alpha wavelength\u003c\/strong\u003e with a very narrow \u003cstrong\u003e7nm bandpass\u003c\/strong\u003e. This dramatically increases contrast by blocking light pollution and natural skyglow, making it possible to capture faint emission nebulae.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong H-Alpha 7nm filter for visual observing?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThis filter is not recommended for visual use. Narrowband filters like this one have extremely low light transmission outside their specified bandpass, making the view through an eyepiece incredibly dim. They are designed for long-exposure astrophotography, where a camera sensor can accumulate light over many minutes or hours.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong 7nm H-Alpha filter help in light-polluted skies?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eLight pollution from city lights is primarily composed of specific wavelengths, such as those from \u003cstrong\u003emercury vapor\u003c\/strong\u003e and \u003cstrong\u003esodium vapor\u003c\/strong\u003e lamps. The Optolong H-Alpha 7nm filter is engineered to block these wavelengths completely, along with unwanted natural skyglow. By only allowing the 656nm light from the nebula to pass through, it creates a near-black sky background, making the nebula's signal stand out dramatically.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow would I use the Optolong H-Alpha 7nm filter to image the Rosette Nebula (Caldwell 49) from my backyard?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eTo image the Rosette Nebula with the Optolong H-Alpha 7nm filter, you would place it in your filter wheel or drawer in front of your monochrome camera. Because the filter is so restrictive, you will need to take long exposures, typically 5 to 20 minutes each, depending on your telescope's focal ratio. You would then stack many of these sub-exposures to create a final, high-contrast black-and-white image revealing the nebula's intricate hydrogen structures.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eI have an LRGB filter set and a monochrome camera. How do I incorporate the Optolong H-Alpha 7nm filter into my workflow?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe Optolong H-Alpha 7nm filter is the perfect first step into advanced LRGB imaging. You would capture your standard Luminance, Red, Green, and Blue data as usual. Then, you capture a separate set of exposures using the H-Alpha filter. In post-processing, you can blend this detailed H-alpha data into your red channel or use it as a separate luminance layer to significantly enhance the detail and \"pop\" of any emission regions within your target.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the \"SHO\" or \"Hubble Palette\" and how does the Optolong H-Alpha 7nm filter fit in?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe \"SHO\" or \"Hubble Palette\" is a popular narrowband imaging technique that assigns data from three different filters to the RGB channels of a color image. The Optolong H-Alpha 7nm filter provides the \"H\" data. Typically:\u003c\/p\u003e\n    \u003cul\u003e\n      \u003cli\u003e\n\u003cstrong\u003eSulfur-II (SII) data\u003c\/strong\u003e is mapped to the Red channel.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eHydrogen-alpha (H-alpha) data\u003c\/strong\u003e is mapped to the Green channel.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eOxygen-III (OIII) data\u003c\/strong\u003e is mapped to the Blue channel.\u003c\/li\u003e\n    \u003c\/ul\u003e\n    \u003cp\u003eThis creates false-color images with high scientific value and striking aesthetic appeal, famously used for images like the \"Pillars of Creation\" (M16).\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\u003eBandpass\u003c\/td\u003e\n\u003ctd\u003e7nm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eCentral Wavelength\u003c\/td\u003e\n\u003ctd\u003e656nm (Hydrogen-alpha)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eAvailable Formats\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, 36mm Round Unmounted\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\"\u003eOptolong H-Alpha 7nm Filter\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\"\u003eProtective Case\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\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":52941912965405,"sku":"OPT-11301","price":223.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":52941912998173,"sku":"OPT-11302","price":321.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":52941913030941,"sku":"OPT-11307","price":265.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-H-Alpha-7nm-Narrowband-Filter-Improved-Version-for-deepsky-nebula-imaging-1_75eadee5-ff2e-45d6-8d76-899d79b53119.jpg?v=1789592351"},{"product_id":"optolong-sii-6-5nm-narrowband-filter","title":"Optolong SII 6.5nm Narrowband Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eIsolates the Sulfur-II (SII) emission line at 672nm\u003c\/li\u003e\n\u003cli\u003eTight 6.5nm bandpass for maximum contrast\u003c\/li\u003e\n\u003cli\u003eEnables imaging in heavily light-polluted skies and during bright moonlight\u003c\/li\u003e\n\u003cli\u003eAdvanced ion-assisted multi-layer coatings for durability and stability\u003c\/li\u003e\n\u003cli\u003eAvailable in 1.25\" Mounted, 2\" Mounted, and 36mm Unmounted sizes\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\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\u003eOptolong SII 6.5nm Narrowband Filter\u003c\/h2\u003e\n\u003cp\u003eThe Optolong SII 6.5nm Narrowband Filter isolates a tight 6.5nm bandpass centered on the 672nm wavelength of doubly ionized sulfur. This precision allows imagers to capture the faint, structural details in emission nebulae, separating the specific SII signal from interfering light pollution and moonlight, which is critical when a 6.5nm window is all you have to work with.\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 6.5nm Bandpass for Sulfur-II Emission\u003c\/h3\u003e\n\u003cp\u003eThis filter is engineered to transmit light from the specific 672nm emission line characteristic of ionized sulfur. The extremely narrow 6.5nm bandpass dramatically increases contrast by rejecting all other wavelengths, rendering the faint structures within nebulae against a dark sky background. This is essential for revealing details that are otherwise lost in the noise of broadband imaging.\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\u003eImaging Through Moonlight and City Skyglow at 672nm\u003c\/h3\u003e\n\u003cp\u003eBy targeting only the 672nm SII line, the Optolong 6.5nm filter effectively blocks common sources of light pollution, including mercury vapor and sodium vapor streetlights. It also rejects natural skyglow from neutral oxygen emission, allowing you to continue imaging even under a full moon. This transforms weeks of potential downtime into productive imaging sessions, maximizing your time under the stars regardless of your location.\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 \"S\" in the Hubble Palette: Building Full-Color Narrowband Images\u003c\/h3\u003e\n\u003cp\u003eThe SII 6.5nm filter is a critical component of the \"SHO\" narrowband imaging trio, alongside Hydrogen-alpha and Oxygen-III filters. By assigning the data from each filter to a different color channel (Sulfur to Red, Hydrogen to Green, Oxygen to Blue), you can create the vibrant, high-contrast images famously associated with the Hubble Space Telescope. This technique reveals the chemical composition and structure of targets like the Pillars of Creation in the Eagle Nebula (M16).\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\u003eIon-Assisted Coatings for 6.5nm Stability and Durability\u003c\/h3\u003e\n\u003cp\u003eOptolong utilizes an advanced ion-assisted deposition coating process to ensure the filter's optical characteristics are precise and long-lasting. This technology produces a dense, scratch-resistant coating and guarantees the stability of the central wavelength (CWL). The 6.5nm bandpass will not deviate due to temperature changes during an imaging session, ensuring consistent, reliable data from dusk till dawn.\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 use for the Optolong SII 6.5nm filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Optolong SII 6.5nm filter is designed for astrophotography of emission nebulae. It isolates the light emitted by ionized sulfur at a wavelength of 672nm, which dramatically increases the contrast of these objects, especially when used from light-polluted areas or as part of a multi-filter color composite image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the 6.5nm bandpass on the Optolong SII filter improve my images?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA narrower bandpass like \u003cstrong\u003e6.5nm\u003c\/strong\u003e rejects more unwanted light from streetlights, moonlight, and natural skyglow compared to wider filters. This results in a darker sky background and higher contrast between your target nebula and the sky, allowing fainter details to be captured.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong SII 6.5nm 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 6.5nm bandpass is so restrictive that it blocks nearly all visible light, making it impossible to see all but the very brightest nebulae. It is designed specifically for long-exposure imaging with sensitive astronomy cameras.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong SII 6.5nm filter perform on the Rosette Nebula (NGC 2244) from a light-polluted location?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Rosette Nebula has significant Sulfur-II emission. Using the Optolong SII 6.5nm filter from a suburban or city location will allow you to capture the delicate filamentary structures within the nebula that would normally be completely washed out by skyglow. It is an essential tool for revealing the full structure of this and similar star-forming regions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat other filters do I need with the Optolong SII 6.5nm for full-color narrowband imaging?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFor full-color \"Hubble Palette\" (SHO) imaging, you will need two other narrowband filters:\n\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eHydrogen-alpha (H-alpha) filter:\u003c\/strong\u003e Captures ionized hydrogen, typically the strongest signal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOxygen-III (OIII) filter:\u003c\/strong\u003e Captures ionized oxygen, which reveals high-energy regions.\u003c\/li\u003e\n\u003c\/ul\u003e\nCombining data from these three filters allows you to create detailed and scientifically interesting false-color images.\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Optolong SII 6.5nm filter work well with my fast f\/4 Newtonian telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile narrowband filters perform optimally with slower focal ratios, Optolong's advanced coatings provide excellent stability. With very fast optical systems (f\/4 and below), some narrowband filters can exhibit a slight shift in their central wavelength. However, the Optolong SII 6.5nm is widely used with fast telescopes and produces excellent results. For critical applications, ensure your imaging software can accommodate precise focus for each filter.\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\u003eNarrowband Interference Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBandpass\u003c\/td\u003e\n\u003ctd\u003e6.5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCentral Wavelength\u003c\/td\u003e\n\u003ctd\u003e672nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Emission Line\u003c\/td\u003e\n\u003ctd\u003eSulfur-II (SII)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating Technology\u003c\/td\u003e\n\u003ctd\u003eIon-Assisted Multi-layer Deposition\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate\u003c\/td\u003e\n\u003ctd\u003eOptical Glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, 36mm Unmounted\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\"\u003eOptolong SII 6.5nm Narrowband Filter (Selected Size)\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\"\u003eProtective Case\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\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":52941916373277,"sku":"OPT-11401","price":223.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":52941916406045,"sku":"OPT-11402","price":321.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":52941916438813,"sku":"OPT-11404","price":265.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-SII-6-5nm-imaging-narrow-band-filter-for-nebulae-photography-1_667ac9a4-9af1-4d52-a692-799938db0908.jpg?v=1789592369"},{"product_id":"optolong-oiii-6-5nm-narrowband-filter","title":"Optolong OIII 6.5nm Narrowband Filter","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e6.5nm Narrowband OIII Filter\u003c\/li\u003e\n\u003cli\u003eCentered on 500nm Wavelength\u003c\/li\u003e\n\u003cli\u003eCaptures both 495.9nm and 500.7nm Emission Lines\u003c\/li\u003e\n\u003cli\u003eBlocks Light Pollution and Skyglow\u003c\/li\u003e\n\u003cli\u003eIdeal for SHO Hubble Palette Imaging\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\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\u003eOptolong OIII 6.5nm Narrowband Filter\u003c\/h2\u003e\n      \u003cp\u003eThe Optolong OIII 6.5nm Narrowband Filter isolates the critical emission lines of doubly-ionized oxygen by passing only a 6.5nm bandpass of light centered at a wavelength of 500nm. This extremely narrow window is engineered to capture both the 495.9nm and 500.7nm OIII lines, which are characteristic of planetary nebulae and supernova remnants, while aggressively rejecting unwanted light pollution and atmospheric skyglow.\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\u003eA 6.5nm Bandpass for High-Contrast OIII Imaging\u003c\/h3\u003e\n      \u003cp\u003eBy restricting the incoming light to a tight 6.5nm window, this filter dramatically increases the contrast between your target nebula and the background sky. The filter doesn't make the nebula brighter; it darkens the sky around it, causing the faint, blue-green structural details of OIII-rich objects to stand out with striking clarity. This is essential for revealing the delicate shells of planetary nebulae or the shock fronts in supernova remnants.\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\u003eRejecting Skyglow by Targeting the 500nm Wavelength\u003c\/h3\u003e\n      \u003cp\u003eThe filter's transmission is precisely centered at 500nm to align with the OIII emission lines. Its primary function is to block out common sources of light pollution, including mercury-vapor and sodium-vapor streetlights, as well as the natural skyglow caused by neutral oxygen emission in the atmosphere. This targeted rejection allows for deep-sky imaging even under moonlit or urban sky conditions.\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\u003eBuilding the Hubble Palette: The \"O\" in SHO Imaging\u003c\/h3\u003e\n      \u003cp\u003eFor astrophotographers, the Optolong OIII 6.5nm filter is a cornerstone of narrowband imaging. It represents the \"O\" in the \"SHO\" Hubble Palette, where it is combined with Hydrogen-alpha and Sulphur-II filters. This technique allows you to create false-color images with stunning detail and color separation, revealing scientific information about the chemical composition of targets like the Pillars of Creation in the Eagle Nebula (M16).\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\u003eIon-Assisted Coatings for Wavelength Stability\u003c\/h3\u003e\n      \u003cp\u003eOptolong utilizes an ion-assisted deposition coating process to ensure the filter's durability and optical precision. This advanced technique produces a hard, scratch-resistant surface and guarantees the central wavelength (CWL) remains stable, with no deviation due to temperature changes during an imaging session. This consistency is critical for maintaining sharp focus and reliable data acquisition over long exposures.\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 purpose of the Optolong OIII 6.5nm filter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe Optolong OIII 6.5nm filter is designed to isolate the light emitted by doubly-ionized oxygen (OIII) from astronomical objects. Its narrow \u003cstrong\u003e6.5nm bandpass\u003c\/strong\u003e dramatically increases contrast by blocking light pollution and natural skyglow, making it ideal for imaging faint emission nebulae, planetary nebulae, and supernova remnants.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Optolong OIII 6.5nm filter make nebulae appear brighter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo, narrowband filters do not increase an object's brightness. Instead, the Optolong OIII 6.5nm filter increases the \u003cstrong\u003econtrast\u003c\/strong\u003e between the nebula and the night sky. By selectively blocking out all light except the specific 500nm OIII wavelength, it makes the background sky much darker, which in turn makes the nebula's structure far more visible.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Optolong OIII 6.5nm filter fit into a SHO (Hubble Palette) imaging setup?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe Optolong OIII 6.5nm filter is the \"O\" component in a standard SHO narrowband imaging set. Data captured with this filter is typically mapped to the green channel in image processing, alongside data from Hydrogen-alpha (red channel) and Sulphur-II (blue channel) filters. This combination creates the iconic, high-detail false-color images popularized by the Hubble Space Telescope.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow would the Optolong OIII 6.5nm filter perform on the Rosette Nebula (Caldwell 49) from a city?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe Rosette Nebula is rich in both Hydrogen-alpha and Oxygen-III. From a light-polluted city, the Optolong OIII 6.5nm filter would be essential for capturing the delicate structures within the nebula's central region. It would effectively cut through the urban skyglow, allowing you to record the faint OIII signal that would otherwise be completely washed out, revealing details in the excavated core of the nebula.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong OIII 6.5nm filter necessary for imaging the Pillars of Creation (M16)?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, it is a critical component for creating a classic Hubble Palette image of M16. While the pillars themselves are dense with Hydrogen-alpha and Sulphur-II, the surrounding nebulosity and the glowing edges of the pillars are illuminated by the intense radiation from young stars, causing them to emit strongly in OIII light. The Optolong OIII 6.5nm filter is required to capture this data and create the famous color separation and depth.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the Optolong OIII 6.5nm filter work with both monochrome and color cameras?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThis filter is designed primarily for use with \u003cstrong\u003emonochrome\u003c\/strong\u003e astronomy cameras. A monochrome sensor's higher sensitivity can take full advantage of the isolated wavelength. While it can be used with a one-shot-color (OSC) camera, the camera's Bayer matrix will only allow the blue and green pixels to detect the OIII signal, significantly reducing efficiency and resolution.\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\u003eAvailable Options\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, 36mm Round Unmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":52941918765341,"sku":"OPT-11501","price":223.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":52941918798109,"sku":"OPT-11502","price":321.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":52941918830877,"sku":"OPT-11504","price":265.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-improved-OIII6-5nm-narrowband-filter-1_8f87788c-6f04-4840-9bab-e49eeb58426d.jpg?v=1789592379"},{"product_id":"optolong-lrgb-h-alpha-7nm-filter-set-5-pcs","title":"Optolong LRGB + H-Alpha 7nm Filter Set","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eComplete 5-Filter LRGB and H-Alpha Set\u003c\/li\u003e\n\u003cli\u003e7nm H-Alpha Filter Centered at 656.3nm\u003c\/li\u003e\n\u003cli\u003eBlocks 589nm Sodium Light Pollution Line\u003c\/li\u003e\n\u003cli\u003eHigh Transmission for Natural Color Balance\u003c\/li\u003e\n\u003cli\u003eAvailable in 1.25\", 2\", and 36mm Unmounted Sizes\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\u003eOptolong LRGB + H-Alpha 7nm Filter Set\u003c\/h2\u003e\n\u003cp\u003eThis 5-filter Optolong LRGB + H-Alpha 7nm Filter Set provides a complete solution for monochrome deep-sky imaging, combining four high-contrast broadband filters with a narrow 7nm Hydrogen-Alpha filter centered at 656.3nm. The LRGB filters are engineered with a spectral gap to block the primary sodium light pollution line at 589nm, ensuring superior color separation on galaxies and star clusters. The included 7nm H-Alpha filter isolates critical emission nebula structures, providing the essential data needed to create deeply detailed composite images from any location.\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 4-Filter LRGB System for Broadband Color\u003c\/h3\u003e\n\u003cp\u003eThe core of this set is the Luminance, Red, Green, and Blue filter quartet, designed for maximum contrast and sharp color differentiation. The OIII emission lines are passed through both the blue and green filters, allowing for high-efficiency capture of planetary nebulae and supernova remnants with natural, balanced color. Extremely high gradients between the passbands ensure that data from each channel is cleanly separated for easier processing.\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\u003eSuppressing City Glow: The 589nm Sodium Line Block\u003c\/h3\u003e\n\u003cp\u003eA key feature of the Optolong LRGB design is the deliberate gap between the green and red filters' transmission windows. This gap is precisely engineered to block the prominent sodium light pollution line at 589nm. By rejecting this common source of urban skyglow, the filters significantly improve color balance and saturation, allowing you to capture cleaner raw data even from suburban skies.\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 7nm, 656.3nm H-Alpha Filter: Isolating Emission Nebulae\u003c\/h3\u003e\n\u003cp\u003eThe fifth filter in the set is a 7nm narrowband H-Alpha filter centered on the 656.3nm wavelength. This filter isolates the most common emission signal in the universe, dramatically increasing the contrast of hydrogen-rich targets like the Orion Nebula (M42) or the North American Nebula (NGC 7000). It aggressively suppresses starlight and background light pollution, revealing faint, intricate nebulosity that is invisible to broadband filters.\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\u003eLRGB+Ha vs. LRGB-Only: A 5-Filter Imaging Workflow\u003c\/h3\u003e\n\u003cp\u003eWhile an LRGB set is sufficient for broadband targets like galaxies and star clusters, the addition of the H-Alpha filter unlocks a new level of detail and creativity. For emission nebulae, you can substitute the Red channel data with the H-Alpha data for a dramatic \"HaRGB\" composite. For galaxies with active star-forming regions, like the Triangulum Galaxy (M33), you can blend the H-Alpha data into the Luminance or Red channels to make the HII regions pop against the stellar background, a technique not possible with a 4-filter set alone.\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\"\u003eHow do I use the H-Alpha filter in the Optolong LRGB+Ha set?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe H-Alpha filter can be used in several ways. You can capture it as a separate channel and blend it into your final LRGB image to enhance red nebulosity. A common technique is to substitute the data from the Red filter with your H-Alpha data to create a high-contrast HaRGB image, or to add it to the Luminance channel for a sharper, more detailed final result.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the 589nm block in this Optolong set eliminate all light pollution?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, but it is highly effective against a primary source. The gap between the green and red filters specifically targets sodium vapor lamps, which are a major component of urban skyglow. While it won't block modern LED lighting, it significantly improves color balance and contrast compared to filters without this feature, especially from older city lighting.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Optolong 7nm H-Alpha filter suitable for very fast telescopes?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, Optolong filters are designed to minimize band-shifting with faster optical systems. While all interference filters experience some degree of shift, the \u003cstrong\u003e7nm bandpass\u003c\/strong\u003e is wide enough to remain effective on most common amateur telescopes, including f\/4 and f\/5 systems, without significant signal loss.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use this Optolong filter set with a color camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis set is designed for \u003cstrong\u003emonochrome cameras\u003c\/strong\u003e. A monochrome sensor allows you to capture data through each filter separately (L, R, G, B, Ha) and combine them during processing for a full-color image. A color camera already has a red, green, and blue filter array built into its sensor, making these filters redundant and ineffective.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eFor a target like the Andromeda Galaxy (M31), is the H-Alpha filter from the Optolong set useful?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. While the Andromeda Galaxy is primarily a broadband target, its spiral arms contain numerous star-forming HII regions that glow in H-Alpha light. Capturing data with the \u003cstrong\u003e7nm H-Alpha filter\u003c\/strong\u003e and blending it into your LRGB data will make these pink and red knots of nebulosity stand out dramatically, adding depth and scientific detail to your final image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow should I approach imaging the Pelican Nebula (IC 5070) with this Optolong LRGB+Ha set?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Pelican Nebula is an emission nebula rich in Hydrogen-Alpha. For this target, you should dedicate most of your imaging time to the \u003cstrong\u003e7nm H-Alpha filter\u003c\/strong\u003e to capture the faint structures and contrast. Use the L, R, G, and B filters primarily to capture star colors, then combine all five channels in processing. You can use the H-Alpha data as a detailed layer for your red channel or as a synthetic luminance.\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\u003eSet Contents\u003c\/td\u003e\n\u003ctd\u003e5 Filters: Luminance, Red, Green, Blue, H-Alpha\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-Alpha Bandwidth\u003c\/td\u003e\n\u003ctd\u003e7nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-Alpha Center Wavelength\u003c\/td\u003e\n\u003ctd\u003e656.3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLight Pollution Rejection\u003c\/td\u003e\n\u003ctd\u003eBlocks 589nm Sodium Line\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, 36mm Unmounted\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\"\u003eLuminance (L) Filter\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\"\u003eRed (R) Filter\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\"\u003eGreen (G) Filter\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\"\u003eBlue (B) Filter\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\"\u003eH-Alpha (Ha) 7nm Filter\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\"\u003eProtective Case\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\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":52941929513245,"sku":"OPT-LRGBH-1.25","price":517.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":52941929546013,"sku":"OPT-LRGBH-2","price":797.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":52941929578781,"sku":"OPT-LRGBH-RD36","price":615.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-HaLRGB-Filter-Kit.webp?v=1789606275"},{"product_id":"optolong-h-alpha-7nm-sii-6-5nm-oiii-6-5nm-filter-set-3-pcs","title":"Optolong Ha 7nm, OIII 6.5nm \u0026 SII 6.5nm Filter Set","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e\n\u003cstrong\u003eH-alpha Filter:\u003c\/strong\u003e 7nm Bandpass centered at 656nm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOxygen-III Filter:\u003c\/strong\u003e 6.5nm Bandpass centered at 500nm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSulphur-II Filter:\u003c\/strong\u003e 6.5nm Bandpass\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHubble Palette Ready:\u003c\/strong\u003e Complete SHO set for tri-band narrowband imaging\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFormat Options:\u003c\/strong\u003e Available in 1.25\" Mounted, 2\" Mounted, or 36mm Unmounted versions\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\u003eOptolong Ha 7nm, OIII 6.5nm \u0026amp; SII 6.5nm Filter Set\u003c\/h2\u003e\n\u003cp\u003eThe Optolong Ha 7nm, OIII 6.5nm \u0026amp; SII 6.5nm Filter Set provides the three essential filters for creating high-contrast Hubble Palette images from light-polluted skies. This trio isolates the key emission lines from nebulae—Hydrogen-alpha at 656nm, Oxygen-III at 500nm, and Sulphur-II—with tight 7nm and 6.5nm bandpasses that reject unwanted skyglow and artificial light sources.\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 Hubble Palette: 6.5nm\/7nm Tri-Band Narrowband Imaging\u003c\/h3\u003e\n\u003cp\u003eThis filter set is engineered specifically for SHO imaging, where data from the Sulphur-II, Hydrogen-alpha, and Oxygen-III filters are mapped to the red, green, and blue channels of a final image. This technique, made famous by the Hubble Space Telescope, reveals incredible structural detail and color separation in emission nebulae like the Rosette Nebula (Caldwell 49) that are impossible to capture in broadband.\u003c\/p\u003e\n\u003cp\u003eDesigned for use with monochrome astronomy cameras or modified DSLRs, each filter isolates a specific emission line, allowing you to capture deep, high-contrast data one channel at a time, even under a bright moon or from a city backyard.\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\u003ePrecision Bandpasses: 7nm Ha, 6.5nm OIII, and 6.5nm SII\u003c\/h3\u003e\n\u003cp\u003eThe effectiveness of a narrowband filter is defined by its bandpass—the narrower, the better the contrast. The 7nm Ha filter captures the dominant 656nm wavelength present in nearly all emission nebulae. The even tighter 6.5nm bandpasses on the OIII and SII filters aggressively reject light pollution and background star signal, making faint nebular structures stand out dramatically.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eH-Alpha (7nm):\u003c\/strong\u003e Reveals the foundational hydrogen structure of nebulae with maximum signal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOIII (6.5nm):\u003c\/strong\u003e Isolates the 500nm blue-green light characteristic of planetary nebulae and supernova remnants, providing crucial detail and color contrast.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSII (6.5nm):\u003c\/strong\u003e Captures the deep red light from ionized sulfur, often tracing shock fronts and dense regions that differ from the Ha data.\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\u003eAdvanced Coatings for 1.25\", 2\", and 36mm Formats\u003c\/h3\u003e\n\u003cp\u003eOptolong utilizes an advanced ion-assisted deposition coating process across all filter sizes, ensuring durability and scratch resistance. This technology also provides a stable central wavelength (CWL) that does not drift with temperature changes during an imaging session, preventing signal loss.\u003c\/p\u003e\n\u003cp\u003eThis meticulous manufacturing process results in excellent transmission at the target wavelengths and high optical density outside the passband. The coatings are engineered to significantly reduce halos around bright stars, a common issue in narrowband imaging, particularly noticeable in the improved OIII filter performance.\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\u003eOptolong 6.5nm\/7nm SHO Set vs. Wider Narrowband Filters\u003c\/h3\u003e\n\u003cp\u003eWhile wider filters, such as 12nm variants, can be a more forgiving starting point, the Optolong 6.5nm\/7nm set offers a significant step up in imaging capability. The primary advantage of the tighter bandpass is superior contrast and the ability to resolve finer nebular details.\u003c\/p\u003e\n\u003cp\u003eThe trade-off is that these filters require longer individual sub-exposure times to gather the same amount of signal as a wider filter. However, because they reject so much more background noise, the final integrated image achieves a much higher signal-to-noise ratio, producing cleaner, sharper, and more detailed results from any location.\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 \"Hubble Palette\" and why do I need this Optolong SHO filter set for it?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \"Hubble Palette\" is an imaging technique where narrowband data is mapped to RGB channels to create false-color images with dramatic detail and contrast. This \u003cstrong\u003eOptolong SHO set\u003c\/strong\u003e provides the three required filters: Sulphur-II (mapped to Red), Hydrogen-alpha (Green), and Oxygen-III (Blue), allowing you to produce these iconic images.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Optolong Ha 7nm, OIII 6.5nm \u0026amp; SII 6.5nm filters with my color camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile technically possible, it is highly inefficient. These filters are designed for \u003cstrong\u003emonochrome cameras\u003c\/strong\u003e. A color camera's Bayer matrix blocks roughly 2\/3 of the incoming light for any given filter, requiring much longer exposures and producing lower-quality results. For color cameras, a multi-bandpass filter (like the L-eNhance or L-eXtreme) is a better choice.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the Optolong 6.5nm OIII filter perform on the Orion Nebula (M42) from my city backyard?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003eOptolong 6.5nm OIII filter\u003c\/strong\u003e will excel on the Orion Nebula (M42) from a light-polluted location. Its tight 6.5nm bandpass will darken the sky background significantly, dramatically increasing the contrast of the delicate, wispy structures in the nebula's core and outer regions, which are rich in Oxygen-III emissions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat's the main benefit of using the Optolong 7nm Ha filter on the Rosette Nebula (Caldwell 49) with my monochrome camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary benefit is immense contrast. The Rosette Nebula (Caldwell 49) is a massive cloud of hydrogen. The \u003cstrong\u003eOptolong 7nm Ha filter\u003c\/strong\u003e isolates its dominant 656nm emission line, rejecting moonlight, skyglow, and broadband light from stars. This allows your monochrome camera to record deep, detailed structural information of the nebula itself, separate from the background.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is the Ha filter in this Optolong set 7nm while the OIII and SII are 6.5nm?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eHydrogen-alpha is typically the strongest signal in most emission nebulae. The slightly wider \u003cstrong\u003e7nm bandpass\u003c\/strong\u003e for the Ha filter ensures maximum signal capture for this critical channel. The OIII and SII signals are often weaker, so the tighter \u003cstrong\u003e6.5nm bandpass\u003c\/strong\u003e is used to maximize contrast by more aggressively rejecting background light pollution and skyglow, improving the signal-to-noise ratio for these fainter details.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo these Optolong narrowband filters require longer exposure times than LRGB filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, significantly longer. LRGB filters have very wide bandpasses to capture as much light as possible. The \u003cstrong\u003eOptolong narrowband filters\u003c\/strong\u003e in this set have extremely narrow 6.5nm and 7nm bandpasses. While this is key to their high-contrast performance, it means individual sub-exposures must be much longer (typically 3-10 minutes or more) to achieve a strong signal.\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 Set\u003c\/td\u003e\n\u003ctd\u003eH-alpha, OIII, SII\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-Alpha Bandpass\u003c\/td\u003e\n\u003ctd\u003e7nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eH-Alpha Central Wavelength\u003c\/td\u003e\n\u003ctd\u003e656nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOIII Bandpass\u003c\/td\u003e\n\u003ctd\u003e6.5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOIII Central Wavelength\u003c\/td\u003e\n\u003ctd\u003e500nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSII Bandpass\u003c\/td\u003e\n\u003ctd\u003e6.5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Sizes\u003c\/td\u003e\n\u003ctd\u003e1.25\" Mounted, 2\" Mounted, 36mm Round Unmounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating Technology\u003c\/td\u003e\n\u003ctd\u003eIon-assisted deposition\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\"\u003eH-Alpha 7nm Filter\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\"\u003eOIII 6.5nm Filter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eSII 6.5nm 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\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/optolong-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOptolong 3-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Optolong","offers":[{"title":"1.25\" Mounted","offer_id":52941930594589,"sku":"OPT-SHO-1.25","price":651.0,"currency_code":"CAD","in_stock":true},{"title":"2\" Mounted","offer_id":52941930627357,"sku":"OPT-SHO-2","price":937.0,"currency_code":"CAD","in_stock":true},{"title":"36mm Round Unmounted","offer_id":52941930660125,"sku":"OPT-SHO-RD36","price":769.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Optolong-improved-NB-filters-SHO6-5nm-narrowband-filter-Kit-1_30b6be85-daea-48f5-b858-b12bd65e15c7.jpg?v=1789592457"}],"url":"https:\/\/davidastro.com\/en-us\/collections\/optolong-narrowband-filters.oembed","provider":"David Astro","version":"1.0","type":"link"}