{"title":"Baader Alan Gee Telecompressors","description":"\u003cp\u003eThe Baader Alan Gee Telecompressor is a focal reducer designed for Schmidt-Cassegrain telescopes and long-focus refractors, often used in front of a binoviewer or diagonal. It shortens the effective focal length to give a wider, brighter field without changing eyepieces.\u003c\/p\u003e\u003cp\u003eThis line includes the Telecompressor Mark II, the Universal 2\" Telecompressor (UAG II), a centring ring for 9.25\" SCTs and a 19mm M36.5 extension tube to fine-tune the reduction factor.\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 and photographic use\u003c\/li\u003e\n\u003cli\u003eCreates a significantly faster focal ratio for brighter images\u003c\/li\u003e\n\u003cli\u003eClose-couples with Baader\/Zeiss and Celestron 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 a reconfigurable air-spaced doublet for visual use with 1.25in star diagonals and binoviewers, and for photography with DSLR and CCD cameras.\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. It fits 8\" and larger Schmidt-Cassegrains (35 mm free aperture); Baader lists the Celestron C5 and C6 as not compatible because of their 27 mm baffle.\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 works with the long optical paths of star diagonals and binoviewers. 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, faster field for visual use with star diagonals and binoviewers and for photography with DSLR and CCD cameras up to APS-C size. It works best at its ideal 121 mm distance to the sensor or field stop, set with its spacer tubes.\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\u003eYes. Baader supplies it for photographic use on Schmidt-Cassegrains with DSLR and CCD cameras. It is recommended for sensors up to APS-C (its fully illuminated image circle is 18 mm; remaining vignetting is easily removed in processing, full-frame shows more) and works best at 121 mm from its rear lens to the sensor, so filter wheels and off-axis guiders must be fitted into that distance. It cannot be used for photography on EdgeHD telescopes.\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\" means mounting the telecompressor lens directly in front of the binoviewer, which is the only way to reach focus with a binoviewer on an SCT. Baader gives an ideal working distance of 121 mm between the rear lens and the focal plane; a longer distance gives a faster f-ratio (about f\/3.5 at 193 mm) but a smaller field of view.\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. For binoviewing it sits directly in front of the binoviewer, behind the star diagonal or T-2 prism; for photography or a 1.25in diagonal it is inserted into the telescope's baffle tube.\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 8\" and larger (not C5\/C6)\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\u003eRequired back focus\u003c\/td\u003e\n\u003ctd\u003e121 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eImage circle\u003c\/td\u003e\n\u003ctd\u003e18 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eClear aperture\u003c\/td\u003e\n\u003ctd\u003e35 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eElements\u003c\/td\u003e\n\u003ctd\u003eAir-spaced doublet, multi-coated\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\"\u003eLens cell with air-spaced doublet\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\"\u003e2 spacer tubes (19 mm each)\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\"\u003eFlanged end ring\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\"\u003eSpacer ring (Teflon)\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\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-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 for visual observation.\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 (a faster f-ratio) but a smaller field of view. 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\u003eIt is a visual telecompressor first: Baader's UAG II manual says it is made exclusively for visual use with Baader binoviewers. The product page allows a camera up to APS-C at 121 mm, but for photography Baader recommends the classic Alan Gee Mark II Telecompressor (#2454400).\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\u003ctr\u003e\n\u003ctd\u003eRequired back focus\u003c\/td\u003e\n\u003ctd\u003e121 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMagnification factor\u003c\/td\u003e\n\u003ctd\u003e0.59x at 121 mm (variable, f\/5.9 to f\/3.5)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eElements\u003c\/td\u003e\n\u003ctd\u003eAir-spaced doublet, multi-coated\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e130 g\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\"\u003eUniversal Alan Gee II in a 2in nosepiece\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\"\u003eT-2 extension tube 7.5 mm\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_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-m36-5-extension-tube-for-alan-gee-ii-19mm","title":"Baader Planetarium M36.5 Extension tube for Alan Gee II – 19mm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e19mm Extension Length\u003c\/li\u003e\n\u003cli\u003eProprietary M36.5 Threading\u003c\/li\u003e\n\u003cli\u003eDesigned for the Baader Alan Gee II Telecompressor\u003c\/li\u003e\n\u003cli\u003eThin-Walled for SCT Baffle Tube Clearance\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\u003eM36.5 Extension tube for Alan Gee II – 19mm\u003c\/h2\u003e\n\u003cp\u003eThe Baader Planetarium M36.5 Extension Tube adds a crucial 19mm of spacing, a required component for achieving the designed working distance with the Alan Gee II Telecompressor on Schmidt-Cassegrain telescopes. Its proprietary M36.5 threading and thin-walled construction are purpose-built to allow the telecompressor to recess deep inside an SCT's main baffle tube, ensuring optimal field 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\u003eThe 19mm Extension for Correct Alan Gee II Positioning\u003c\/h3\u003e\n\u003cp\u003eThe Alan Gee II Telecompressor provides a variable focal reduction from f\/5.9 down to f\/3.5, but its optical correction is highly dependent on precise spacing. This 19mm extension tube is engineered to place the telecompressor at the correct distance within an SCT's optical path. Without it, the corrector sits too far forward, preventing it from achieving its full correction potential and compromising edge-of-field sharpness.\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\u003eM36.5 Threading: A Purpose-Built Interface for SCTs\u003c\/h3\u003e\n\u003cp\u003eTo fit inside the narrow baffle tube of a C8 or similar SCT, this extension utilizes a thin-walled design with a proprietary M36.5 thread. This specific construction is a necessary trade-off; a standard, thicker T-2 extension would not physically fit. This part is intended solely to complement the Alan Gee II, allowing you to achieve perfect spacing, experiment with different working distances, or replace a lost original component.\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\"\u003eWhy do I need this 19mm M36.5 extension for my Alan Gee II on a Celestron 8\" SCT?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eOn a C8, the Alan Gee II corrector must be recessed inside the main baffle tube to reach the correct working distance for optimal performance. This 19mm extension provides the exact spacing required, while its thin-walled M36.5 design allows it to physically fit where a standard T-2 extension cannot.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use this 19mm M36.5 extension to connect my Alan Gee II to a T-2 filter wheel?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo. This extension uses a proprietary \u003cstrong\u003eM36.5 thread\u003c\/strong\u003e and is not compatible with the standard T-2 (M42x0.75) system. It is designed exclusively for spacing the Alan Gee II telecompressor itself.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat problem does the 19mm M36.5 extension solve for the Alan Gee II?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt solves the critical spacing problem in Schmidt-Cassegrain telescopes. Without this extension, the Alan Gee II corrector is positioned too far from the focal plane, which can lead to poor optical correction, especially at the edge of the field of view.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 19mm M36.5 extension tube compatible with other telecompressors?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this is a dedicated part designed specifically for the Baader Alan Gee II Telecompressor. Its unique M36.5 thread and dimensions are not intended for use with other optical accessories.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eI lost an extension for my Alan Gee II, is this the correct replacement?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The Alan Gee II system uses extensions like this to achieve different reduction factors and proper spacing. This 19mm tube is an original Baader component for replacing a lost part or for experimenting with custom spacing configurations.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhere can I find instructions for using the 19mm M36.5 extension tube?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eDetailed instructions, including diagrams showing how to configure the extensions for different reduction factors, can be found in the official manual for the \u003cstrong\u003eAlan Gee II Telecompressor\u003c\/strong\u003e.\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\u003eType of Adapter\u003c\/td\u003e\n\u003ctd\u003eExtension\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical length (mm)\u003c\/td\u003e\n\u003ctd\u003e19\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":52913244438813,"sku":"BAA-2454411","price":30.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/BaaderPlanetarium-M36-5-Extension-tube-for-Alan-Gee-II-19mm-1_6ecca8e6-f0e7-4f5c-833c-74c95312ada5.jpg?v=1789088656"},{"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 the Celestron 9.25\" Schmidt-Cassegrain OTA\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 the Celestron 9.25\" Schmidt-Cassegrain telescope. 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\" 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\" SCT optical tube. 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 the larger Celestron 9.25\" Schmidt-Cassegrain telescope. 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 tube of the Celestron 9.25\" SCT (46 mm) is wider than that of the 8\" model (37 mm). 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\" SCT. The Celestron C11 and C14 take the Alan Gee II without a ring. 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. Insert the Alan Gee II into the centering ring, then insert both fully into the baffle tube of the telescope. Clamp it in place as usual with the Celestron Visual Back or another 2\"\/T-2 adapter.\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\" 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-int\/collections\/baader-alan-gee-telecompressors.oembed","provider":"David Astro","version":"1.0","type":"link"}