{"product_id":"baader-planetarium-m54-extension-tube-15-mm","title":"Baader Planetarium M54 Extension Tube – 15 mm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eAdds a precise 15 mm of optical path length\u003c\/li\u003e\n\u003cli\u003eStandard M54 (M54x0.75) threads for modern imaging trains\u003c\/li\u003e\n\u003cli\u003eMachined from metal for rigidity and stability\u003c\/li\u003e\n\u003cli\u003eEssential for achieving correct back focus with flatteners and reducers\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\u003eM54 Extension Tube – 15 mm\u003c\/h2\u003e\n\u003cp\u003eThis M54 Extension Tube adds a fixed 15 mm of length to any M54-threaded optical train. This precise 15 mm spacing is essential for matching the required back focus of field flatteners, coma correctors, and focal reducers to your camera sensor's position, ensuring edge-to-edge sharpness in your images.\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 Critical Back Focus with 15mm of M54 Extension\u003c\/h3\u003e\n\u003cp\u003eModern optical correctors demand precise spacing to function correctly. This 15 mm extension tube serves as a rigid, reliable component for bridging the gap between your corrector and camera, helping you achieve the exact spacing needed for optimal performance. Its fixed length provides a stable, flex-free connection that complex, adjustable adapters can lack.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFixed 15 mm Length:\u003c\/strong\u003e Provides a non-adjustable, solid increase in your optical path length, ensuring consistent and repeatable spacing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eM54 Thread Standard:\u003c\/strong\u003e Connects seamlessly with the M54 threads found on a wide range of modern correctors, filter wheels, off-axis guiders, and large-format astronomy cameras.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBack Focus Solution:\u003c\/strong\u003e An essential building block for assembling imaging trains that meet the strict spacing tolerances of high-performance optical systems.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the primary use for the M54 Extension Tube – 15 mm?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary use of the \u003cstrong\u003eM54 Extension Tube – 15 mm\u003c\/strong\u003e is to add a precise 15 mm of distance within an astrophotography imaging train. This is most often required to achieve the exact \u003cstrong\u003eback focus\u003c\/strong\u003e distance specified by a focal reducer, field flattener, or coma corrector for a specific camera sensor.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I know if I need a 15 mm M54 extension tube for my setup?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYou need to calculate the total back focus of your current imaging train. Start with the corrector's required back focus (e.g., 55 mm is common), then subtract the back focus of your camera and the thickness of any components in between (like a filter wheel or off-axis guider). If the remaining distance you need to fill is 15 mm, this tube is the correct component.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs this M54 Extension Tube threaded on the inside and outside?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. Standard extension tubes like this one feature \u003cstrong\u003emale M54 threads\u003c\/strong\u003e on one end and \u003cstrong\u003efemale M54 threads\u003c\/strong\u003e on the other. This allows them to be inserted between two other M54-threaded components, such as a corrector and a camera adapter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I stack this 15 mm M54 Extension Tube with other extenders?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. You can stack multiple extension tubes to achieve a specific distance. For example, if you need 35 mm of spacing, you could combine this 15 mm tube with a 20 mm tube. Using a single, fixed-length tube is generally preferred for rigidity where possible.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill this 15 mm extension tube work with my Celestron EdgeHD telescope and 0.7x reducer?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt can be part of the solution. The Celestron 0.7x reducer for EdgeHD scopes requires a very specific back focus. Many imagers use M54-threaded components to build a rigid imaging train off this reducer. This 15 mm tube could be the final piece you need to achieve the correct spacing, depending on your camera and other accessories.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eI'm connecting a ZWO camera to an M54 filter wheel. Could this 15 mm M54 tube be useful?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this is a common scenario. If your corrector, filter wheel, and camera adapters don't naturally add up to the required back focus distance, this 15 mm tube can be inserted into the M54-threaded train to make up the difference. It's a simple and effective way to ensure your spacing is perfect for sharp stars.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\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\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"Default Title","offer_id":52913168187677,"sku":"BAA-2958715","price":53.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/BaaderPlanetarium-M54-Extension-Tube-15-mm-1_2a77fb0d-d88c-4890-b3f8-061835ea91d1.jpg?v=1789087004","url":"https:\/\/davidastro.com\/en-us\/products\/baader-planetarium-m54-extension-tube-15-mm","provider":"David Astro","version":"1.0","type":"link"}