{"product_id":"askar-3nm-colour-magic-ultra-oiii-sii-e1-filter-2","title":"Askar 3nm Colour Magic Ultra OIII\/SII E2 Filter - 2\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDual-bandpass design captures OIII (500.7nm) and SII (672nm) simultaneously\u003c\/li\u003e\n\u003cli\u003eNarrow 3.7nm (OIII) and 4.0nm (SII) FWHM for high-contrast imaging\u003c\/li\u003e\n\u003cli\u003ePeak transmittance of 85% ensures high signal throughput\u003c\/li\u003e\n\u003cli\u003eDeep ≥OD5 blocking from 200-1100nm eliminates unwanted light pollution\u003c\/li\u003e\n\u003cli\u003eStandard 2\" filter format with 1.85mm substrate thickness\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eAskar 3nm Colour Magic Ultra OIII\/SII E2 Filter - 2\"\u003c\/h2\u003e\n\u003cp\u003eThe Askar 3nm Colour Magic Ultra OIII\/SII E2 Filter is engineered to solve a common problem for color camera imagers: capturing the full Hubble Palette. This dual-bandpass filter isolates nebula emissions at 500.7nm (OIII) and 672nm (SII) with narrow 3.7nm and 4.0nm bandpasses, respectively. With a peak transmittance of 85% and deep OD5 blocking across the 200-1100nm spectrum, this filter allows you to gather the missing Sulfur-II data needed for SHO compositions, even from light-polluted locations.\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 672nm + 500.7nm Solution for Color Camera SHO Imaging\u003c\/h3\u003e\n\u003cp\u003eWhile standard duo-narrowband filters for color cameras typically capture Hydrogen-alpha and Oxygen-III, they leave out the critical Sulfur-II signal. The Askar Ultra E2 filter is designed specifically to fill this gap. By passing light at 672nm (SII) and 500.7nm (OIII), it allows you to collect the remaining two channels for a full SHO dataset without a filter wheel or monochrome camera.\u003c\/p\u003e\n\u003cp\u003eCombine the data from this filter with Hydrogen-alpha data (captured separately or with an Hα\/OIII filter) to unlock vibrant, detailed SHO images. This approach makes the celebrated Hubble Palette accessible and efficient for anyone using a one-shot-color astronomy camera.\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\u003e3.7nm \u0026amp; 4.0nm Bandpasses for Maximum Contrast\u003c\/h3\u003e\n\u003cp\u003eThis filter achieves its high contrast through extremely narrow full-width at half-maximum (FWHM) values: 3.7nm for OIII and 4.0nm for SII. These tight bandpasses aggressively reject streetlights, moonlight, and natural skyglow, causing faint nebula structures to stand out against a dark background. The ≥OD5 blocking from 200nm to 1100nm ensures no out-of-band wavelengths contaminate the image.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePeak Transmittance (85%):\u003c\/strong\u003e Despite the narrow bandpasses, the filter allows 85% of the crucial OIII and SII light to reach your sensor, preventing excessively long exposure times.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHalo Control:\u003c\/strong\u003e As part of Askar's \"Ultra\" series, this filter is optimized to minimize halos around bright stars, a common issue with narrowband filters.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrecision Substrate:\u003c\/strong\u003e The filter is built on a glass substrate with a parallelism of 30 arcseconds, maintaining the sharpness of your optical system.\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 primary purpose of the Askar Ultra E2 OIII\/SII filter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Askar Ultra E2 is a specialized dual-narrowband filter designed for \u003cstrong\u003ecolor camera users\u003c\/strong\u003e who want to capture images in the Hubble Palette (SHO). It isolates the Oxygen-III (OIII) and Sulfur-II (SII) emission lines, allowing you to collect the \"S\" and \"O\" channels to complement your Hydrogen-alpha (\"H\") data.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I create an SHO image with the Askar Ultra E2 and a color camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYou will need to capture two sets of images. First, use a filter that passes Hydrogen-alpha (like an L-eXtreme, L-eNhance, or a dedicated Hα filter) to get your \"H\" data. Second, use this Askar Ultra E2 filter to capture your \"S\" and \"O\" data simultaneously. In post-processing, you will split the channels from both images and combine them using a tool like PixInsight's ChannelCombination to assign Hα to Red, SII to Green, and OIII to Blue (or any variation you prefer).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Askar Ultra E2 filter with a monochrome camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile it is designed for color cameras, you can use it with a monochrome camera. However, because it passes both OIII and SII light at the same time, you cannot separate the two signals onto the mono sensor. For monochrome imaging, using individual OIII and SII filters is the standard and more flexible approach.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy does the Askar Ultra E2 filter have 3.7nm and 4.0nm bandpasses instead of just \"3nm\"?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \"3nm\" is a class or series designation. The actual measured FWHM is \u003cstrong\u003e3.7nm ± 0.3nm for OIII\u003c\/strong\u003e and \u003cstrong\u003e4.0nm ± 0.3nm for SII\u003c\/strong\u003e. These precise, ultra-narrow bandpasses are what provide the exceptional contrast and light pollution rejection by isolating the specific nebula emission lines from background skyglow.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow would the Askar Ultra E2 filter perform on the Wizard Nebula (NGC 7380) from a city?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Wizard Nebula (NGC 7380) is rich in all three SHO gasses. From a city, the Askar Ultra E2 filter's narrow 3.7nm\/4.0nm bandpasses would be highly effective at cutting through light pollution to reveal the intricate structures in the OIII and SII regions. It would darken the sky background significantly, increasing the contrast and making the faint nebulosity visible in your exposures.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Askar Ultra E2 filter work well with my fast f\/4 telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eUltra-narrowband filters like this one can experience some band-shifting with very fast optical systems (typically f\/4 and below). While it will still provide a significant contrast boost, you may see a slight reduction in transmission compared to its peak 85% rating. The filter's performance is optimal for systems at f\/4.5 and slower, but it remains a powerful tool for light pollution suppression even on faster scopes.\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\u003eFWHM (OIII)\u003c\/td\u003e\n\u003ctd\u003e3.7nm ± 0.3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFWHM (SII)\u003c\/td\u003e\n\u003ctd\u003e4.0nm ± 0.3nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCenter Wavelength (CWL)\u003c\/td\u003e\n\u003ctd\u003e500.7nm (OIII) \u0026amp; 672nm (SII)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePeak Transmittance\u003c\/td\u003e\n\u003ctd\u003e85%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlocking Property\u003c\/td\u003e\n\u003ctd\u003e≥OD5 @ 200-1100nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSubstrate Thickness\u003c\/td\u003e\n\u003ctd\u003e1.85 ± 0.05mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Finish\u003c\/td\u003e\n\u003ctd\u003e60\/40\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParallelism\u003c\/td\u003e\n\u003ctd\u003e30″\u003c\/td\u003e\n\u003c\/tr\u003e\n\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\"\u003eAskar 3nm Colour Magic Ultra OIII\/SII E2 Filter - 2\"\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\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/www.sharpstar-optics.com\/download_list_1\/7.html\" target=\"_blank\"\u003e\u003csvg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 640 512\" class=\"DAV-img-box\"\u003e\u003cpath fill=\"#0047a7\" d=\"M128 32C92.7 32 64 60.7 64 96l0 256 64 0 0-256 384 0 0 256 64 0 0-256c0-35.3-28.7-64-64-64L128 32zM19.2 384C8.6 384 0 392.6 0 403.2C0 445.6 34.4 480 76.8 480l486.4 0c42.4 0 76.8-34.4 76.8-76.8c0-10.6-8.6-19.2-19.2-19.2L19.2 384z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eDownload Software \u0026amp; Drivers\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/askar-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eAskar 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Askar","offers":[{"title":"Default Title","offer_id":50344442036509,"sku":"ASK-ASKAR2DBE2","price":612.66,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Askar-Colour-Magic-E2-Filter.jpg?v=1757644814","url":"https:\/\/davidastro.com\/fr-us\/products\/askar-3nm-colour-magic-ultra-oiii-sii-e1-filter-2","provider":"David Astro","version":"1.0","type":"link"}