{"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":24.0,"currency_code":"USD","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","url":"https:\/\/davidastro.com\/fr-us\/products\/baader-planetarium-m36-5-extension-tube-for-alan-gee-ii-19mm","provider":"David Astro","version":"1.0","type":"link"}