{"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","url":"https:\/\/davidastro.com\/fr\/products\/optolong-oiii-3nm-narrowband-filter","provider":"David Astro","version":"1.0","type":"link"}