{"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 9¼\"","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 9¼\"\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\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\"\u003eDownload 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":30.0,"currency_code":"USD","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\/fr-us\/products\/baader-planetarium-alan-gee-mark-ii-centering-ring-for-sc-9-1-4-inch","provider":"David Astro","version":"1.0","type":"link"}