{"product_id":"starizona-m48-extension-20mm","title":"Starizona M48 Extension - 20mm","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eAdds 20mm of spacing to an imaging train\u003c\/li\u003e\n\u003cli\u003eFeatures male and female M48 threads\u003c\/li\u003e\n\u003cli\u003eEnsures precise back focus adjustment\u003c\/li\u003e\n\u003cli\u003eRigid, single-piece construction\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\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\u003eStarizona M48 Extension - 20mm\u003c\/h2\u003e\n\u003cp\u003eThe Starizona M48 Extension adds a precise 20mm of length to an M48-threaded imaging train. This single-piece tube is designed to bridge a 20mm gap between components, ensuring you can achieve the critical back focus distance required by your specific field flattener or focal reducer.\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\u003eM48 Spacing for 20mm of Back Focus\u003c\/h3\u003e\n\u003cp\u003eAchieving a perfectly flat field of view depends on placing your camera's sensor at the exact back focus distance specified by your optical corrector. This Starizona extension provides a fixed 20mm of spacing, making it a crucial component for hitting that target. By threading its male M48 connection into a female M48 port on your reducer or other accessory, you create a rigid, non-flexing segment in your optical train. You can combine this 20mm extension with other spacers to dial in the exact distance your system requires.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\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 primary purpose of the Starizona M48 20mm Extension?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Starizona M48 20mm Extension is used to add exactly 20mm of distance within an M48-threaded imaging train. This is essential for achieving the correct back focus—the specific distance required between a focal reducer or field flattener and the camera sensor for sharp, coma-free stars across the entire image.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eMy corrector requires 55mm of back focus, and my camera's flange is 35mm from the sensor. Will this 20mm extension work?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, in that scenario, the Starizona M48 20mm Extension is the perfect solution. You have a 20mm gap to fill (55mm required - 35mm existing = 20mm needed), and this extension is designed to fill that exact space, assuming all your components use M48 threads.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I connect the Starizona M48 Extension directly to an M42 T-ring?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, not directly. The Starizona 20mm Extension uses M48 threads, which are larger than the M42 threads found on standard T-rings. To connect them, you would need a separate M48-to-M42 step-down adapter, which would also factor into your total back focus calculation.\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\u003eThread Type\u003c\/td\u003e\n\u003ctd\u003eM48 (Male\/Female)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eExtension Length\u003c\/td\u003e\n\u003ctd\u003e20mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/starizona-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eStarizona Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Starizona","offers":[{"title":"Default Title","offer_id":68045014303005,"sku":"STZ-EXTM48-20","price":40.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Starizona-M48-Extension-20mm-Long-1_e0957980-9ccf-41ac-83af-951e7a8559a5.jpg?v=1794410568","url":"https:\/\/davidastro.com\/en-int\/products\/starizona-m48-extension-20mm","provider":"David Astro","version":"1.0","type":"link"}