{"title":"Baader Field Flatteners, Reducers \u0026 Coma Correctors","description":"\u003cp\u003eBaader Planetarium correctors fix the optical aberrations that appear at the edge of the field in astrophotography. The MPCC Mark III is a 2\" coma corrector for Newtonian telescopes, the RCC I Rowe Coma Corrector serves fast Newtonians, and the M68 Field Flattener gives flat fields with refractors.\u003c\/p\u003e\u003cp\u003eFor visual use and imaging with long-focus instruments, the Alan Gee Telecompressor Mark II and UAG II shorten the focal length, with a centring ring for 9.25\" SCTs.\u003c\/p\u003e","products":[{"product_id":"baader-alan-gee-telecompressor-mark-ii","title":"Baader Alan Gee Telecompressor Mark II","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDramatically widens the field of view of Schmidt-Cassegrain telescopes\u003c\/li\u003e\n\u003cli\u003eEngineered to produce a sharp, flat field for visual observation\u003c\/li\u003e\n\u003cli\u003eCreates a significantly faster focal ratio for brighter images\u003c\/li\u003e\n\u003cli\u003eSpecifically designed for close-coupling with select binoviewers\u003c\/li\u003e\n\u003cli\u003eRequires precise spacing for optimal optical correction\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\u003eBaader Alan Gee Telecompressor Mark II\u003c\/h2\u003e\n\u003cp\u003eThe Baader Alan Gee Telecompressor Mark II is a specialized optical corrector designed to solve the primary limitation of Schmidt-Cassegrain telescopes: their narrow, long-focus field of view. This telecompressor significantly reduces the effective focal length of your SCT, delivering a wider, flatter, and brighter image. It is engineered specifically for visual observers using binoviewers, transforming the observing experience on large deep-sky objects.\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\u003eWiden Your SCT's Field for Rich-Field Views\u003c\/h3\u003e\n\u003cp\u003eStandard SCTs excel at high-power planetary views but struggle to frame large objects like the Andromeda Galaxy (M31) or the Pleiades (M45). The Alan Gee Telecompressor Mark II corrects this by shortening the telescope's light cone, expanding your true field of view to encompass these expansive targets. The result is a sharp, flat field that turns your SCT into a capable rich-field instrument.\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\u003eOptimized for Baader, Zeiss, and Celestron Binoviewers\u003c\/h3\u003e\n\u003cp\u003eUnlike generic focal reducers, the Alan Gee Mark II is a purpose-built solution for binoviewing. Its design requires critical \"close coupling\" — a very specific and short distance between the compressor and the binoviewer prisms. This precise spacing is essential to achieve a fully illuminated and corrected field, limiting its use to specific Baader, Zeiss, and Celestron binoviewer models that can physically achieve this connection.\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\u003eAlan Gee Mark II vs. Standard f\/6.3 Reducers\u003c\/h3\u003e\n\u003cp\u003eWhile a standard f\/6.3 reducer\/corrector offers a moderate increase in field of view, the Alan Gee Telecompressor is a more aggressive and specialized design. It provides a greater degree of focal reduction, but this comes with a critical trade-off.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard f\/6.3 Reducer:\u003c\/strong\u003e Offers more forgiving back-focus, making it compatible with a wide range of cameras and accessories. It's a general-purpose solution for both imaging and visual use.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBaader Alan Gee Mark II:\u003c\/strong\u003e Provides a wider, flatter field specifically for visual use with binoviewers. Its strict spacing requirements make it unsuitable for general imaging, but for its intended purpose, it delivers superior edge-of-field correction and a more immersive wide-field experience.\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 won't the Baader Alan Gee Mark II work with my Denkmeier or Tele Vue binoviewer?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Alan Gee Mark II's optical design requires extremely close spacing to the binoviewer's prisms to function correctly. Most binoviewers have a long optical path (e.g., through a power-switch diagonal) that makes this physically impossible. It is specifically designed for direct, close-coupled attachment to certain Baader, Zeiss, and Celestron models.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Alan Gee Mark II for astrophotography?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis telecompressor is not recommended for general astrophotography. It is optimized for visual use and creating a flat field for the human eye within a binoviewer. Achieving the correct spacing with a camera sensor, filter wheel, and off-axis guider is typically not feasible and will result in poor optical correction.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Alan Gee Mark II affect the image brightness in my Celestron 11\" SCT?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eBy reducing the telescope's effective focal ratio, the telecompressor concentrates the same amount of light into a smaller area. This creates a brighter image surface, which is especially beneficial for observing faint, extended objects like the Veil Nebula (NGC 6960). The background sky will appear brighter, but the nebula's contrast against it will increase.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the \"close coupling\" mentioned for the Alan Gee Mark II?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\"Close coupling\" refers to the minimal physical distance required between the last lens of the telecompressor and the focal plane (or in this case, the prisms of the binoviewer). The optical corrections of the Alan Gee design are only valid at this specific, short distance. Increasing this distance will introduce significant aberrations like coma and field curvature.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo I need to modify my SCT to use the Baader Alan Gee Mark II?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo permanent modification is needed, but you will need the correct adapters to thread the telecompressor directly to your binoviewer and then attach the entire assembly to your telescope's visual back. It replaces the standard diagonal in your optical train.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill this telecompressor help me fit the entire Orion Nebula (M42) in the view of my 8\" SCT with a binoviewer?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this is precisely the kind of application the Alan Gee Mark II is designed for. A standard 8\" SCT with a binoviewer often cannot frame the full extent of M42's nebulosity. This telecompressor widens the field sufficiently to capture the entire object, from the Trapezium core to the fainter outer loops, in a single immersive view.\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\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.09\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003eMulti-Coated (MC)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical Design\u003c\/td\u003e\n\u003ctd\u003eField Flattener, Telecompressor\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatible telescopes\u003c\/td\u003e\n\u003ctd\u003eSchmidt-Cassegrain\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical length (mm)\u003c\/td\u003e\n\u003ctd\u003e\u0026lt; 50\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_Alan_Gee_II_Telecompressor_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium Alan Gee II Telecompressor Manual\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\/baader-planetarium-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eBaader Planetarium Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"Default Title","offer_id":44967374094621,"sku":"BAA-2454400","price":401.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Baader-Alan-Gee-Telecompressor-Mark-II-1__02804.1597111079.1280.1280.jpg?v=1684341616"},{"product_id":"baader-m68-field-flattener","title":"Baader M68 Field Flattener","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eCorrects field curvature for astrophotography\u003c\/li\u003e\n\u003cli\u003eDesigned for Baader APO 95\/560 Travel Companion\u003c\/li\u003e\n\u003cli\u003eCompatible with Zeiss APQ apochromatic refractors\u003c\/li\u003e\n\u003cli\u003eFeatures large M68 threads for a secure, wide-aperture connection\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\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\u003eBaader M68 Field Flattener\u003c\/h2\u003e\n      \u003cp\u003eThe Baader M68 Field Flattener is a dedicated optical corrector engineered to eliminate field curvature in specific high-end refractors. It is precisely matched to the optical system of the Baader APO 95\/560 Travel Companion and legendary Zeiss APQ apochromats. By using a robust M68 thread, this flattener ensures a rigid, wide-aperture imaging train capable of illuminating large format sensors without vignetting.\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\u003eM68 Connection for Flat-Field Imaging\u003c\/h3\u003e\n      \u003cp\u003eThis corrector utilizes the Baader M68 system, a large-diameter thread standard chosen to provide a rigid connection and an unobstructed light path for modern imaging sensors. Unlike smaller M42 or M48 threads that can introduce vignetting with full-frame and larger chips, the M68 connection maintains the full illumination of the optical system. This ensures that stars remain pinpoint across the entire frame, from the center to the corners, without compromising brightness at the edges.\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\u003eDesigned for the Baader APO 95\/560 and Zeiss APQ Refractors\u003c\/h3\u003e\n      \u003cp\u003eThis is not a generic flattener; it is a specialized corrector calculated specifically for the Baader APO 95\/560 Travel Companion and classic Zeiss APQ refractors. Field flatteners must be matched to the focal length and optical design of a telescope to work correctly. This unit provides the precise correction required by these premium apochromatic systems, ensuring that their exceptional native image sharpness is delivered across the entire photographic field.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\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 purpose of the Baader M68 Field Flattener?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe Baader M68 Field Flattener is an optical accessory designed for astrophotography. It corrects for field curvature, a natural aberration in refracting telescopes that causes stars at the edge of the field of view to appear out of focus. By inserting this flattener into the optical path, you can achieve sharp, pinpoint stars across your entire camera sensor.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Baader M68 Field Flattener with any telescope?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo. This field flattener is specifically designed and optically matched for use with the \u003cstrong\u003eBaader APO 95\/560 Travel Companion\u003c\/strong\u003e and \u003cstrong\u003eZeiss APQ\u003c\/strong\u003e apochromatic refractors. Using it with other telescopes will not provide the correct optical correction and will likely result in poor image quality.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhy does the Baader M68 Field Flattener use M68 threads?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe M68 thread provides a larger clear aperture than more common M48 or M42 threads. This is critical for preventing vignetting (dimming at the corners of the image) when using cameras with large, full-frame sensors. The larger thread also creates a more rigid and stable connection for heavy imaging trains.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Baader M68 Field Flattener suitable for visual observing?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eWhile you could technically place an eyepiece behind it, this accessory is designed purely for photographic use. Field flatteners are not necessary for visual observation, as the human eye is much more tolerant of field curvature than a camera sensor. Its primary function is to create a flat focal plane for imaging.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Baader M68 Field Flattener perform with a full-frame camera on the Baader APO 95\/560?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe Baader M68 Field Flattener is engineered to provide excellent correction across large sensor formats when paired with the Baader APO 95\/560. The M68 connection is specifically intended to support full-frame sensors, ensuring the telescope's high-contrast, apochromatic performance is maintained to the corners of the frame for objects like the Andromeda Galaxy (M31) or the North American Nebula (NGC 7000).\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat adapters are needed to connect my camera to the Baader M68 Field Flattener?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe required adapters depend on your specific camera and the necessary back focus distance. Baader Planetarium offers a comprehensive system of M68 adapters and extension tubes to achieve the correct spacing for various DSLR, mirrorless, and dedicated astronomy cameras. You will need to consult the flattener's documentation for the precise back focus requirement and select the appropriate adapters from the M68 lineup.\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\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.39\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    \n  \u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/baader-planetarium-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eBaader Planetarium Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"Default Title","offer_id":44967374160157,"sku":"BAA-2458260","price":1056.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Baader-M68-Field-Flattener-1__24858.1597111083.1280.1280.jpg?v=1684341642"},{"product_id":"baader-mpcc-mark-iii-multi-purpose-coma-corrector-2","title":"Baader MPCC Mark III (Multi Purpose Coma Corrector) - 2\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eCorrects Coma in Newtonians as Fast as f\/3.5\u003c\/li\u003e\n\u003cli\u003eZero Change in Focal Length or Field Size\u003c\/li\u003e\n\u003cli\u003eFits Standard 2\" Focusers\u003c\/li\u003e\n\u003cli\u003eFeatures Baader Planetarium Phantom Group™ Multicoatings\u003c\/li\u003e\n\u003cli\u003eIntegrated M48 Male Thread for Filter and Accessory Connection\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\u003eBaader MPCC Mark III (Multi Purpose Coma Corrector) - 2\"\u003c\/h2\u003e\n\u003cp\u003eThe Baader MPCC Mark III (Multi Purpose Coma Corrector) corrects coma in Newtonian telescopes as fast as f\/3.5, delivering pinpoint stars across the entire photographic field. Unlike other correctors, the MPCC III mounts in any 2\" focuser and introduces zero change to your telescope's focal length, ensuring an f\/4 system remains a true f\/4 imaging platform.\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\u003ePinpoint Stars Down to f\/3.5 without Changing Focal Length\u003c\/h3\u003e\n\u003cp\u003eThe primary function of the MPCC Mark III is to eliminate the distracting, comet-shaped stars at the edge of the field inherent in fast parabolic mirrors. This modern optical design is optimized for today's fast astrographs, providing exceptional correction down to f\/3.5. Crucially, the corrector achieves this without any magnification factor, preserving your telescope's native focal ratio and field of view for wide, fast 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\u003ePhantom Group Coatings: Full Spectrum Transmission from UV to NIR\u003c\/h3\u003e\n\u003cp\u003eEvery air-to-glass surface of the MPCC Mark III features Baader's proprietary Phantom Group™ wideband multicoating. This treatment ensures the highest possible light transmission while minimizing reflections and scatter. The result is a brighter, higher-contrast image, with a spectral response that extends from the ultraviolet to the near-infrared, making it ideal for the full range of modern color and monochrome imaging sensors.\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 Modular System for Any 2\" Focuser\u003c\/h3\u003e\n\u003cp\u003eDesigned as the market's most versatile coma corrector, the MPCC Mark III integrates seamlessly into virtually any imaging train. It slides into any 2\" focuser and features an M48 male thread on the camera side, allowing direct connection to filter wheels, off-axis guiders, and camera adapters. This modularity allows you to configure the corrector for both photographic and visual use, adapting to your specific equipment needs.\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\u003eMPCC Mark III vs. Original MPCC: From f\/4.5 to f\/3.5\u003c\/h3\u003e\n\u003cp\u003eWhile the original Baader MPCC was designed for Newtonians from f\/4.5 to f\/6, the Mark III represents a significant optical upgrade. The improved lens design provides sharp, pinpoint stars on systems as fast as f\/3.5. This key enhancement makes the MPCC Mark III the ideal choice for imagers using modern, fast Newtonian astrographs who demand sharp stars edge-to-edge.\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\"\u003eWill the Baader MPCC Mark III change my telescope's focal length?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo. The MPCC Mark III is a \"zero-power\" corrector, meaning it does not alter the native focal length or focal ratio of your telescope. An f\/4 Newtonian will remain an f\/4 Newtonian, preserving its original field of view and image scale.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the fastest telescope I can use with the MPCC Mark III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe MPCC Mark III is designed to provide excellent coma correction on Newtonian telescopes as fast as \u003cstrong\u003ef\/3.5\u003c\/strong\u003e. It also works exceptionally well on slower systems up to f\/6.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I connect the MPCC Mark III to my DSLR for imaging the North American Nebula (NGC 7000)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYou will need a standard M48 T-ring for your camera brand (e.g., Canon or Nikon). The T-ring threads directly onto the MPCC Mark III's M48 threads. Depending on your camera's sensor depth, you may need an additional T-2 spacer, such as the optional Baader T-Spacer (# 245 8405), to achieve the optimal 55mm back focus for sharp stars.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Baader MPCC Mark III for visual observing with my 10\" f\/4.7 Dobsonian?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The MPCC Mark III is available in a visual configuration that includes adapters to connect a standard 1.25\" or 2\" eyepiece. It will provide wide, sharp fields of view, making it excellent for observing large star clusters like the Hercules Cluster (M13) without distracting coma at the edges.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat makes the Phantom Group coatings on the MPCC Mark III special?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eBaader's Phantom Group™ coatings are a proprietary 7-layer multicoating that provides extremely high light transmission across a very wide spectral range from UV to NIR. This minimizes light loss and reflections, resulting in higher contrast and brighter images compared to standard coatings.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo I need special adapters to use the MPCC Mark III?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe base MPCC Mark III unit fits any standard 2\" focuser. For photographic use, you will need an M48 T-ring for your specific camera. For visual use, you will need an eyepiece holder that threads onto the M48 port. The corrector is sold in different configurations to provide the necessary adapters for your intended application.\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\u003eProduct Name\u003c\/td\u003e\n\u003ctd\u003eBaader MPCC Mark III (Multi Purpose Coma Corrector)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrector Type\u003c\/td\u003e\n\u003ctd\u003eNewtonian Coma Corrector\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBarrel Size\u003c\/td\u003e\n\u003ctd\u003e2\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptimized Focal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/3.5 to f\/6\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length Modification\u003c\/td\u003e\n\u003ctd\u003eNone (1.0x)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoatings\u003c\/td\u003e\n\u003ctd\u003ePhantom Group™ Multicoatings\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCamera-Side Thread\u003c\/td\u003e\n\u003ctd\u003eM48 x 0.75 Male Thread (2\" Filter Thread)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAvailable Configurations\u003c\/td\u003e\n\u003ctd\u003ePhotographic, Visual, and Visual\/Photographic Sets\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.08 (Photographic)\u003cbr\u003e0.21 (Visual and Photographic)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransmission\u003c\/td\u003e\n\u003ctd\u003e98%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003ePhantom Coating® Group\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInner Diameter \/ Clear Aperture (mm)\u003c\/td\u003e\n\u003ctd\u003e44\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOuter Connection (eyepiece\/-camera-sided)\u003c\/td\u003e\n\u003ctd\u003eM42 x 0.75 (T-2), M48\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInner Connection (lens sided)\u003c\/td\u003e\n\u003ctd\u003eM48\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOuter Connection (lens sided)\u003c\/td\u003e\n\u003ctd\u003eø 2\" (50.8mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eImage Scale\u003c\/td\u003e\n\u003ctd\u003e1:1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eClamping System\u003c\/td\u003e\n\u003ctd\u003eScrew clamps (Visual and Photographic)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInner Connection (eyepiece\/-camera-sided)\u003c\/td\u003e\n\u003ctd\u003eø 1¼\" (31.75 mm) (Visual and Photographic)\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\"\u003eBaader MPCC Mark III Coma Corrector Body\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\"\u003eDust Caps\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 2\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003cp\u003e\u003csmall\u003eNote: Package contents may vary depending on the specific visual or photographic configuration selected.\u003c\/small\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_MPCC_Mark_III_Coma_Corrector_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium MPCC Mark III Coma Corrector Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_MPCC_Backfocus_from_T-2_and_M48_Surfaces_Drawing.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium MPCC Backfocus from T-2 and M48 Surfaces Drawing\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_MPCC_Mark_III_Coma_Corrector_Product_Information.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium MPCC Mark III Coma Corrector Product Information\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\/baader-planetarium-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eBaader Planetarium Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"Photographic","offer_id":44967374258461,"sku":"BAA-2458400A","price":271.0,"currency_code":"CAD","in_stock":true},{"title":"Visual and Photographic","offer_id":44967374291229,"sku":"BAA-2458403","price":328.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/mpcc-version_750x750__20426.1625854161.1280.1280.jpg?v=1684341656"},{"product_id":"baader-rcc-i-rowe-coma-corrector","title":"Baader RCC I Rowe Coma Corrector","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eTriplet optical design corrects coma in fast Newtonian telescopes\u003c\/li\u003e\n\u003cli\u003eEngineered for a long back focus to accommodate complex imaging trains\u003c\/li\u003e\n\u003cli\u003eIdeal for use with Off-Axis Guiders, Adaptive Optics, and filter wheels\u003c\/li\u003e\n\u003cli\u003eFeatures Baader Planetarium's Phantom Group multi-coatings for maximum transmission\u003c\/li\u003e\n\u003cli\u003eConnects to accessories via a standard T-2 thread\u003c\/li\u003e\n\u003cli\u003eRemovable stop ring allows the corrector to sit deeper inside the focuser\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\u003eBaader RCC I Rowe Coma Corrector\u003c\/h2\u003e\n\u003cp\u003eThe Baader RCC I Rowe Coma Corrector employs a new triplet lens design to deliver sharp, coma-free stars across the field in fast Newtonian imaging systems, connecting to your camera and accessories via a universal T-2 thread. This corrector is engineered specifically for imagers who require significant back focus to accommodate accessories like off-axis guiders, adaptive optics, or filter wheels without compromising optical correction.\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\u003eTriplet Optical Design for Fast Newtonian Coma Correction\u003c\/h3\u003e\n\u003cp\u003eUnlike simpler coma corrector designs, the RCC I uses a triplet lens system designed by Dave Rowe to neutralize the coma inherent in parabolic mirrors. Each air-to-glass surface receives Baader's Phantom Group multi-coatings, ensuring that light transmission is maximized for brighter images and higher contrast, which is critical when imaging faint deep-sky objects.\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\u003eLong Back Focus: Integrating Guiders, Filter Wheels, and AO\u003c\/h3\u003e\n\u003cp\u003eThe primary advantage of the RCC I is its generous back focus distance, measured from its T-2 thread. This provides ample space to install a complete imaging train, including an off-axis guider for precise tracking, an adaptive optics unit for atmospheric correction, and a filter wheel for multi-band imaging, all behind the corrector.\u003c\/p\u003e\n\u003cp\u003eFor additional mechanical flexibility, the corrector's threaded stop ring can be removed. This allows the body of the RCC I to be inserted deeper into the focuser, helping you reach focus with a wide variety of telescope and accessory combinations.\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\u003eBaader RCC I vs. MPCC Mark III: Choosing Your Coma Corrector\u003c\/h3\u003e\n\u003cp\u003eBaader offers two excellent coma correctors, and the choice depends entirely on your imaging train's back focus requirements.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBaader MPCC Mark III:\u003c\/strong\u003e This corrector is designed for the standard 55mm back focus common with DSLRs and many dedicated astronomy cameras. It is the ideal choice for simpler setups where an OAG or filter wheel is not needed, offering excellent correction in a compact form factor.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBaader RCC I:\u003c\/strong\u003e The RCC I is the solution for complex setups. Its long back focus is specifically intended to accommodate the added path length of off-axis guiders, filter wheels, and adaptive optics. If your imaging train exceeds 55mm, the RCC I is the necessary choice.\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 makes the Baader RCC I different from other coma correctors?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe key differentiator of the \u003cstrong\u003eBaader RCC I Rowe Coma Corrector\u003c\/strong\u003e is its significantly long back focus. This is a deliberate design choice that allows astrophotographers to place accessories like an \u003cstrong\u003eOff-Axis Guider (OAG)\u003c\/strong\u003e, \u003cstrong\u003eAdaptive Optics (AO)\u003c\/strong\u003e unit, or a \u003cstrong\u003efilter wheel\u003c\/strong\u003e between the corrector and the camera sensor, which is not possible with standard coma correctors.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I achieve the correct spacing for my DSLR with the Baader RCC I?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile the RCC I provides a long back focus, you will need to add extension tubes to reach the correct spacing for your camera. Baader recommends their \u003cstrong\u003eVariLock 46 T-2 Extension Tube (#2956946)\u003c\/strong\u003e, which is continuously variable and includes a helpful pre-engraved mark to quickly set the perfect distance for a standard DSLR with a T-2 ring.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Baader RCC I work with my 8\" f\/4 Newtonian for imaging the Andromeda Galaxy (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the RCC I is an excellent match for an 8\" f\/4 Newtonian. Its triplet design is made for fast optical systems and will produce sharp, point-like stars across the entire field of view, which is essential for capturing the full expanse of large targets like the Andromeda Galaxy (M31).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Baader RCC I for visual observing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Baader RCC I is specifically designed and optimized for astrophotography. While you could theoretically use it for visual observation, its optical prescription is not intended for eyepieces and may not produce optimal visual results. For visual coma correction, Baader's MPCC is a more suitable choice.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eI have a ZWO OAG and filter wheel; is the RCC I a better choice than the MPCC for my Celestron 8\" f\/5 Newtonian?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. For your f\/5 Newtonian, the combination of a ZWO OAG and filter wheel will require much more than the standard 55mm of back focus. The \u003cstrong\u003eBaader RCC I\u003c\/strong\u003e is the correct choice here, as its long back focus is specifically designed to accommodate exactly this kind of accessory stack, whereas the MPCC would not provide enough spacing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat do the Phantom Group Coatings on the RCC I do?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003ePhantom Group Coatings\u003c\/strong\u003e are Baader Planetarium's proprietary 7-layer broadband anti-reflection coatings. They are applied to every air-to-glass surface on the RCC I's triplet lenses to maximize light transmission and minimize reflections, resulting in higher image contrast and brightness, especially on faint nebulae and galaxies.\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\u003eOptical Design\u003c\/td\u003e\n\u003ctd\u003eRowe Coma Corrector (Triplet)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eApplication\u003c\/td\u003e\n\u003ctd\u003eComa correction for fast Newtonian telescopes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoatings\u003c\/td\u003e\n\u003ctd\u003ePhantom Group Multi-Coatings\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCamera Connection\u003c\/td\u003e\n\u003ctd\u003eT-2 (M42x0.75) Male Thread\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.17\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003ePhantom Coating® Group\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBarrel Size (in)\u003c\/td\u003e\n\u003ctd\u003e2\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptimized for focal ratio\u003c\/td\u003e\n\u003ctd\u003ef\/4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOuter Connection (eyepiece\/-camera-sided)\u003c\/td\u003e\n\u003ctd\u003eM42 x 0.75 (T-2), M48\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInner Connection (lens sided)\u003c\/td\u003e\n\u003ctd\u003eM48\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOuter Connection (lens sided)\u003c\/td\u003e\n\u003ctd\u003eø 2\" (50.8mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWorking Range\u003c\/td\u003e\n\u003ctd\u003ef\/3.5 – f\/6\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eImage Scale\u003c\/td\u003e\n\u003ctd\u003e1:1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/baader-planetarium-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eBaader Planetarium Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"Default Title","offer_id":44967374487837,"sku":"BAA-2956800","price":277.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/Baader-RCC-I-Rowe-Coma-Corrector-1__47999.1597111088.1280.1280.jpg?v=1684341672"},{"product_id":"baader-planetarium-alan-gee-universal-2-inch-telecompressor-uag-ii","title":"Baader Planetarium Alan Gee Universal 2\" Telecompressor (UAG II)","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eUnique telecompressor designed for visual use with binoviewers\u003c\/li\u003e\n\u003cli\u003eBased on the flat-field Alan Gee design by Roland Christen of AstroPhysics\u003c\/li\u003e\n\u003cli\u003eEnables wide, 2-inch-like fields of view with 1.25\" binoviewer systems\u003c\/li\u003e\n\u003cli\u003eHoused in a standard 2\" nosepiece with a T-2 thread on the telescope side\u003c\/li\u003e\n\u003cli\u003eCompatible with Schmidt-Cassegrain and EdgeHD optical tubes\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\u003eAlan Gee Universal 2\" Telecompressor (UAG II)\u003c\/h2\u003e\n\u003cp\u003eThe Alan Gee Universal 2\" Telecompressor (UAG II) is a unique focal reducer, derived from a Roland Christen design, engineered to deliver a flat, wide field of view in Schmidt-Cassegrain telescopes. Its proven optical group is housed in a versatile 2\" barrel with T-2 threads, making it the only telecompressor on the market specifically designed to work seamlessly with binoviewers. This configuration allows you to achieve the expansive fields of a 2\" eyepiece system while using your preferred 1.25\" binoviewer.\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\u003eFlat-Field Correction for 8\" to 14\" SCTs\u003c\/h3\u003e\n\u003cp\u003eOriginally designed by Roland Christen of AstroPhysics, the Alan Gee telecompressor was created to solve the dual problems of long focal ratios and field curvature in standard Schmidt-Cassegrain telescopes. The UAG II brings this powerful optical correction to a wider audience, delivering sharp, flat fields suitable for both visual observation and imaging.\u003c\/p\u003e\n\u003cp\u003eWhile standard reducers can increase the field of view, they often introduce other aberrations. The UAG II is designed to maintain high image quality across the field, making it an ideal match for Celestron EdgeHD telescopes and other modern SCTs where edge-to-edge sharpness is critical.\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\u003eAchieve 2\" Fields with Your 1.25\" Binoviewer\u003c\/h3\u003e\n\u003cp\u003eThe standout capability of the UAG II is its compatibility with binoviewers. For years, SCT users wanting immersive, two-eyed views were limited by the narrow fields of 1.25\" systems. The UAG II eliminates this trade-off by significantly widening the field of view, creating an experience comparable to using a low-power 2\" eyepiece.\u003c\/p\u003e\n\u003cp\u003eWhen paired with a binoviewer like the Baader Maxbright® II and wide-field 1.25\" eyepieces, the UAG II can frame enormous deep-sky objects like the Andromeda Galaxy (M31) or the North American Nebula (NGC 7000) in their entirety. It provides the benefit of a 2\" system without the cost and weight of a hypothetical 2\" binoviewer.\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\u003eFlexible Connectivity: 2\" Nosepiece and T-2 Threads\u003c\/h3\u003e\n\u003cp\u003eThe UAG II is built for system flexibility. Its primary body is a 2\" nosepiece that slides directly into any 2\" diagonal or focuser, such as the Baader 2\" ClickLock clamp. For a more rigid, direct connection, the telescope side also features a T-2 female thread.\u003c\/p\u003e\n\u003cp\u003eThis T-2 thread allows you to integrate the reducer into a solid, threaded optical train, which is ideal for binoviewing. You can attach it directly to a Baader T-2 prism diagonal, which in turn connects to your binoviewer, creating a compact and secure wide-field system. The actual focal reduction is variable and depends on the back focus distance you establish between the UAG II and your eyepieces, giving you control over the final magnification.\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 makes the Alan Gee Universal Telecompressor (UAG II) different from other reducers?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe UAG II is the only telecompressor on the market specifically designed to work correctly for \u003cstrong\u003evisual observation with a binoviewer\u003c\/strong\u003e. Most reducers are optimized for imaging sensors and can introduce aberrations when used visually with the long light paths of binoviewers. The UAG II, based on a Roland Christen flat-field design, corrects for field curvature in SCTs while dramatically expanding the field of view for two-eyed observing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the UAG II improve binoviewing on a Celestron 8\" EdgeHD telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eOn an 8\" EdgeHD or standard SCT, a binoviewer provides comfortable viewing but with a very restricted field of view. The UAG II telecompressor widens this field significantly, allowing you to see large objects in context. For example, instead of seeing just the core of the Orion Nebula (M42), you can frame the entire structure from the Trapezium out to the fainter nebulosity in a single view.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the focal reduction of the Alan Gee Universal Telecompressor (UAG II) a fixed value?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, the reduction factor is variable. It depends entirely on the \u003cstrong\u003edistance between the UAG II's optics and the eyepiece field stop\u003c\/strong\u003e (or camera sensor). A longer distance results in a stronger reduction effect and a wider field. This allows you to customize the reduction by adding or removing T-2 extension tubes in your optical train.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Alan Gee Universal Telecompressor (UAG II) for imaging?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile its primary design is for visual use, especially with binoviewers, its flat-field optical design by Roland Christen makes it suitable for imaging. It can help flatten the field of standard SCTs and provide a wider perspective for cameras with smaller sensors. The variable reduction allows you to fine-tune your imaging scale.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the best way to connect the UAG II to a Baader Maxbright II Binoviewer on my SCT?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFor the most rigid and compact setup, it is recommended to build a fully T-2 threaded system. A typical high-performance configuration would be:\n\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eSCT Visual Back -\u0026gt; Baader T-2 Prism Diagonal -\u0026gt; \u003cstrong\u003eUAG II Telecompressor\u003c\/strong\u003e -\u0026gt; Baader Maxbright II Binoviewer.\u003c\/li\u003e\n\u003c\/ul\u003e\nThis creates a solid, threaded connection that prevents any flexure and ensures perfect alignment.\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo I need a 2\" diagonal to use the UAG II?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNot necessarily. While the UAG II has a 2\" nosepiece that can be used in any 2\" diagonal, its real flexibility comes from the T-2 thread on the telescope side. This allows for direct integration into T-2 systems like the Baader T-2 Prism or FlipMirror II, bypassing the need for a larger 2\" diagonal entirely.\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\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.13\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAR-Coating\u003c\/td\u003e\n\u003ctd\u003eMulti-Coated (MC)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical Design\u003c\/td\u003e\n\u003ctd\u003eField Flattener, Telecompressor\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatible telescopes\u003c\/td\u003e\n\u003ctd\u003eSchmidt-Cassegrain\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical length (mm)\u003c\/td\u003e\n\u003ctd\u003e\u0026lt; 50\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eUsage\u003c\/td\u003e\n\u003ctd\u003eMaxBright II Binocular\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_Universal_Alan_Gee_II_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium Universal Alan Gee II Manual\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\/baader-planetarium-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eBaader Planetarium Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"Default Title","offer_id":52913118970141,"sku":"BAA-2454405","price":286.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/BaaderPlanetarium-Alan-Gee-Universal-2-Telecompressor-UAG-II-1_48379d86-580f-4eff-a149-5d2f283f9573.jpg?v=1789086429"},{"product_id":"baader-planetarium-alan-gee-mark-ii-centering-ring-for-sc-9-1-4-inch","title":"Baader Planetarium Alan Gee Mark II Centering Ring for SC 9.25\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eAdapts Alan Gee II Telecompressor to larger SCTs\u003c\/li\u003e\n\u003cli\u003eEnsures precise optical alignment\u003c\/li\u003e\n\u003cli\u003eDesigned for Celestron 9.25\" and 11\" Schmidt-Cassegrain OTAs\u003c\/li\u003e\n\u003cli\u003ePrevents off-axis aberrations like coma\u003c\/li\u003e\n\u003cli\u003eRequired for optimal telecompressor 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\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\u003eAlan Gee Mark II Centering Ring for SC 9.25\"\u003c\/h2\u003e\n\u003cp\u003eThis Alan Gee Mark II Centering Ring is the essential component for adapting the Baader Alan Gee II Telecompressor to Celestron 9.25\" and 11\" Schmidt-Cassegrain telescopes. It ensures the telecompressor is perfectly centered on the telescope's optical axis, a mandatory requirement for achieving sharp, coma-free images across the field.\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 Centering for the Alan Gee II Telecompressor\u003c\/h3\u003e\n\u003cp\u003eA telecompressor's position relative to the primary optical axis is critical. Even a slight misalignment can introduce significant off-axis aberrations, degrading image quality. This centering ring is machined to bridge the specific gap between the Alan Gee II's threads and the larger baffle tube of bigger SCTs, guaranteeing perfect axial alignment every time you attach it.\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\u003eDedicated Fit for Celestron 9.25\" and 11\" SCTs\u003c\/h3\u003e\n\u003cp\u003eThis ring is not a generic adapter; it is specifically designed for the baffle tube dimensions of Celestron's 9.25\" and 11\" SCT optical tubes. Using the telecompressor on these models without this ring will result in a poorly centered optical train, negating the benefits of the Alan Gee II's design. This component is a required part of the system for imagers using these specific telescope apertures.\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 purpose of the Alan Gee II Centering Ring for SC 9¼\"?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIts sole purpose is to adapt the \u003cstrong\u003eBaader Alan Gee Mark II Telecompressor\u003c\/strong\u003e for use with larger \u003cstrong\u003eCelestron 9.25\" and 11\" Schmidt-Cassegrain telescopes\u003c\/strong\u003e. It ensures the telecompressor is held perfectly on the optical axis, which is crucial for preventing image defects.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is a specific centering ring needed for the Alan Gee II on a 9.25\" SCT?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe baffle tubes of the Celestron 9.25\" and 11\" SCTs have a different diameter than the 8\" models for which the Alan Gee II was originally designed. This ring compensates for that size difference, ensuring the telecompressor's optical elements are precisely centered with the telescope's optics to avoid introducing coma and astigmatism.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs this ring compatible with Celestron 8\" SCTs or EdgeHD models?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo. This ring is specifically for the non-EdgeHD Celestron 9.25\" and 11\" SCTs. The standard Alan Gee II Telecompressor attaches directly to a C8 without this ring. EdgeHD models have a different optical design and require different reducer solutions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I install the Alan Gee II Centering Ring on my Celestron 9.25\" telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eInstallation is straightforward. You first thread the centering ring onto the rear cell of your Celestron 9.25\" or 11\" SCT. Then, you thread the Alan Gee Mark II Telecompressor into the centering ring. This ensures the entire assembly is secure and optically aligned.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Alan Gee II Telecompressor without this centering ring on my C9.25?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, you cannot. Attempting to attach the telecompressor without this ring will result in a loose fit and a severely misaligned optical train. This will produce poor quality images with significant aberrations. The ring is a mandatory component for these specific telescopes.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes this Alan Gee II Centering Ring work with other telecompressors?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis ring is designed exclusively for the Baader Alan Gee Mark II Telecompressor. It is not intended to work with reducers from other manufacturers, as thread specifications and spacing requirements can vary significantly.\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\u003eCompatibility\u003c\/td\u003e\n\u003ctd\u003eBaader Alan Gee Mark II Telecompressor\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTelescope Compatibility\u003c\/td\u003e\n\u003ctd\u003eCelestron 9.25\" and 11\" Schmidt-Cassegrain Telescopes (non-EdgeHD)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.01\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\"\u003eAlan Gee II Centering Ring for SC 9¼\"\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:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Baader_Planetarium_Alan_Gee_II_Telecompressor_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBaader Planetarium Alan Gee II Telecompressor Manual\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003eFor Alan Gee II Telecompressor\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\/baader-planetarium-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eBaader Planetarium Warranty Policy\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"Default Title","offer_id":52913244995869,"sku":"BAA-2454410","price":40.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/BaaderPlanetarium-Alan-Gee-Mark-II-Centering-Ring-for-SC-9-1_cb259621-4286-4607-99c5-99f605315708.jpg?v=1789088666"}],"url":"https:\/\/davidastro.com\/en-us\/collections\/baader-field-flatteners-reducers-and-coma-correctors.oembed","provider":"David Astro","version":"1.0","type":"link"}