{"product_id":"dark-clear-skies-m52-0-75-threaded-extension-tube-20-mm","title":"Dark Clear Skies M52 × 0.75 Threaded Extension Tube – 20 mm","description":"\u003cdiv class=\"dcs-m52-ext20\" style=\"color:#173442;font-size:16px;line-height:1.7;max-width:100%;box-sizing:border-box;overflow-wrap:break-word;\"\u003e\n  \u003csection style=\"background:#102d3b;color:#fff;border-radius:16px;padding:28px;margin:0 0 20px;box-sizing:border-box;\"\u003e\n    \u003cdiv style=\"display:flex;flex-wrap:wrap;align-items:center;gap:24px;\"\u003e\n      \u003cdiv style=\"flex:1 1 260px;min-width:0;\"\u003e\n        \u003cp style=\"margin:0 0 12px;color:#82dfe1;font-size:12px;font-weight:700;letter-spacing:1.5px;\"\u003eDARK CLEAR SKIES · IMAGING ACCESSORIES\u003c\/p\u003e\n        \u003ch2 style=\"margin:0 0 16px;color:#fff;font-size:clamp(26px,3.2vw,36px);line-height:1.15;letter-spacing:-0.5px;\"\u003eAdd 20 mm to your M52 setup.\u003c\/h2\u003e\n        \u003cp style=\"margin:0;color:#e5eff2;font-size:16px;line-height:1.7;\"\u003eComplete the spacing in your imaging train without changing thread size. The \u003cstrong style=\"color:#fff;\"\u003eDark Clear Skies M52 × 0.75 Extension Tube\u003c\/strong\u003e provides a fixed \u003cstrong style=\"color:#fff;\"\u003e20 mm back-focus contribution\u003c\/strong\u003e between compatible threaded components.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cfigure style=\"flex:1 1 240px;min-width:0;margin:0;background:#fff;border-radius:12px;padding:12px;box-sizing:border-box;\"\u003e\n        \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0523\/1650\/4241\/files\/dcs-m52-20mm-clean-threaded.png?v=1794148346\" alt=\"Studio-style view of the Dark Clear Skies M52 extension tube with its branding and threaded opening\" width=\"1536\" height=\"1024\" loading=\"lazy\" style=\"display:block;width:100%;max-width:100%;height:auto;border:0;margin:0;\"\u003e\n      \u003c\/figure\u003e\n    \u003c\/div\u003e\n  \u003c\/section\u003e\n\n  \u003cdiv style=\"display:flex;flex-wrap:wrap;gap:12px;margin:0 0 30px;\"\u003e\n    \u003cdiv style=\"flex:1 1 150px;min-width:0;background:#eef6f7;border:1px solid #dce8eb;border-radius:10px;padding:16px;box-sizing:border-box;\"\u003e\n\u003cstrong style=\"display:block;color:#102d3b;font-size:22px;line-height:1.3;\"\u003eM52 × 0.75\u003c\/strong\u003e\u003cspan style=\"display:block;margin-top:5px;font-size:14px;\"\u003eThread specification\u003c\/span\u003e\n\u003c\/div\u003e\n    \u003cdiv style=\"flex:1 1 150px;min-width:0;background:#eef6f7;border:1px solid #dce8eb;border-radius:10px;padding:16px;box-sizing:border-box;\"\u003e\n\u003cstrong style=\"display:block;color:#102d3b;font-size:22px;line-height:1.3;\"\u003e20 mm\u003c\/strong\u003e\u003cspan style=\"display:block;margin-top:5px;font-size:14px;\"\u003eSpecified extension length\u003c\/span\u003e\n\u003c\/div\u003e\n    \u003cdiv style=\"flex:1 1 150px;min-width:0;background:#eef6f7;border:1px solid #dce8eb;border-radius:10px;padding:16px;box-sizing:border-box;\"\u003e\n\u003cstrong style=\"display:block;color:#102d3b;font-size:22px;line-height:1.3;\"\u003eFixed spacing\u003c\/strong\u003e\u003cspan style=\"display:block;margin-top:5px;font-size:14px;\"\u003eThreaded connection at each end\u003c\/span\u003e\n\u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003csection style=\"margin:0 0 30px;\"\u003e\n    \u003ch2 style=\"margin:0 0 12px;color:#102d3b;font-size:25px;line-height:1.3;\"\u003eA practical link in your imaging train\u003c\/h2\u003e\n    \u003cp style=\"margin:0 0 12px;\"\u003eWhen your camera and accessories leave a 20 mm gap in the required spacing, this extension provides a straightforward way to make up that distance. It is intended for \u003cstrong\u003ematching M52 × 0.75 threaded connections\u003c\/strong\u003e, with external and internal threaded ends and Dark Clear Skies branding.\u003c\/p\u003e\n    \u003cp style=\"margin:0;\"\u003eUse it as part of a compatible camera-adapter or accessory arrangement where that extra distance is needed. This is a mechanical extension tube, not a focal reducer, Barlow lens or thread-size converter.\u003c\/p\u003e\n  \u003c\/section\u003e\n\n  \u003csection style=\"margin:0 0 30px;padding:22px;border:1px solid #dce8eb;border-radius:12px;background:#f7fafb;box-sizing:border-box;\"\u003e\n    \u003cp style=\"margin:0 0 7px;color:#08717c;font-size:12px;font-weight:700;letter-spacing:1.2px;\"\u003eCHECK YOUR CONNECTION\u003c\/p\u003e\n    \u003ch2 style=\"margin:0 0 12px;color:#102d3b;font-size:25px;line-height:1.3;\"\u003eM52 is the diameter. 0.75 is the pitch.\u003c\/h2\u003e\n    \u003cp style=\"margin:0 0 12px;\"\u003eBoth measurements matter. \u003cstrong\u003eM52 × 0.75\u003c\/strong\u003e specifies a nominal 52 mm thread diameter with a 0.75 mm pitch. Match an external thread to a corresponding internal thread, and check that the parts can seat fully without interference.\u003c\/p\u003e\n    \u003cp style=\"margin:0;border-left:3px solid #087f8b;padding:8px 0 8px 14px;\"\u003e\u003cstrong\u003eNot interchangeable with M48, M54 or M68.\u003c\/strong\u003e This tube retains the M52 connection; a different diameter or pitch requires the appropriate separate adapter.\u003c\/p\u003e\n  \u003c\/section\u003e\n\n  \u003csection style=\"margin:0 0 30px;\"\u003e\n    \u003ch2 style=\"margin:0 0 12px;color:#102d3b;font-size:25px;line-height:1.3;\"\u003eAccount for the full distance to your sensor\u003c\/h2\u003e\n    \u003cp style=\"margin:0 0 16px;\"\u003eStart with the spacing required by your telescope, reducer or field flattener. Subtract the distance already occupied by the camera’s sensor recess and the rest of your assembled accessories. Include any filter-related spacing adjustment specified for your system.\u003c\/p\u003e\n    \u003cdiv style=\"background:#102d3b;color:#fff;padding:22px;border-radius:12px;box-sizing:border-box;\"\u003e\n      \u003cp style=\"margin:0 0 9px;color:#82dfe1;font-size:12px;font-weight:700;letter-spacing:1.2px;\"\u003eWORKED EXAMPLE · ILLUSTRATIVE ONLY\u003c\/p\u003e\n      \u003cp style=\"margin:0 0 10px;color:#fff;font-size:clamp(22px,3vw,29px);line-height:1.35;font-weight:700;\"\u003e55 mm − 35 mm = 20 mm\u003c\/p\u003e\n      \u003cp style=\"margin:0;color:#e5eff2;font-size:15px;\"\u003eA setup requiring 55 mm, with 35 mm already accounted for, needs another 20 mm. This tube provides that specified extension when the connections match. \u003cstrong style=\"color:#fff;\"\u003e55 mm is an example, not a universal requirement.\u003c\/strong\u003e\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cp style=\"margin:14px 0 0;color:#4b6570;font-size:14px;\"\u003eUse the manufacturer’s reference surface and the distance to the sensor, not simply the outside of the camera body. The stated 20 mm is the spacing contribution; do not add the overlapping engaged threads again.\u003c\/p\u003e\n  \u003c\/section\u003e\n\n  \u003cfigure style=\"margin:0 0 28px;padding:16px;background:#fff;border:1px solid #dce8eb;border-radius:12px;box-sizing:border-box;\"\u003e\n    \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0523\/1650\/4241\/files\/dcs-m52-20mm-clean-hero.png?v=1794148326\" alt=\"Studio-style presentation of the DCS M52 20 mm extension tube beside its labelled packaging\" width=\"1536\" height=\"1024\" loading=\"lazy\" style=\"display:block;width:100%;max-width:100%;height:auto;max-height:360px;object-fit:contain;border:0;margin:0;\"\u003e\n    \u003cfigcaption style=\"margin:12px 0 0;text-align:center;color:#4b6570;font-size:14px;\"\u003eM52 × 0.75 thread · 20 mm specified back-focus length\u003c\/figcaption\u003e\n  \u003c\/figure\u003e\n\n  \u003csection style=\"margin:0 0 28px;\"\u003e\n    \u003ch2 style=\"margin:0 0 14px;color:#102d3b;font-size:25px;line-height:1.3;\"\u003eSpecifications at a glance\u003c\/h2\u003e\n    \u003ctable style=\"width:100%;border-collapse:collapse;table-layout:fixed;font-size:15px;line-height:1.5;\"\u003e\n      \u003ctbody\u003e\n        \u003ctr style=\"background:#eef6f7;\"\u003e\n\u003cth scope=\"row\" style=\"width:42%;padding:12px;text-align:left;vertical-align:top;border-bottom:1px solid #dce8eb;color:#102d3b;\"\u003eBrand\u003c\/th\u003e\n\u003ctd style=\"padding:12px;vertical-align:top;border-bottom:1px solid #dce8eb;\"\u003eDark Clear Skies\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth scope=\"row\" style=\"padding:12px;text-align:left;vertical-align:top;border-bottom:1px solid #dce8eb;color:#102d3b;\"\u003eProduct type\u003c\/th\u003e\n\u003ctd style=\"padding:12px;vertical-align:top;border-bottom:1px solid #dce8eb;\"\u003eFixed-length threaded extension tube\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr style=\"background:#eef6f7;\"\u003e\n\u003cth scope=\"row\" style=\"padding:12px;text-align:left;vertical-align:top;border-bottom:1px solid #dce8eb;color:#102d3b;\"\u003eThread specification\u003c\/th\u003e\n\u003ctd style=\"padding:12px;vertical-align:top;border-bottom:1px solid #dce8eb;\"\u003eM52 × 0.75 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth scope=\"row\" style=\"padding:12px;text-align:left;vertical-align:top;border-bottom:1px solid #dce8eb;color:#102d3b;\"\u003eSpecified back-focus length\u003c\/th\u003e\n\u003ctd style=\"padding:12px;vertical-align:top;border-bottom:1px solid #dce8eb;\"\u003e20 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr style=\"background:#eef6f7;\"\u003e\n\u003cth scope=\"row\" style=\"padding:12px;text-align:left;vertical-align:top;border-bottom:1px solid #dce8eb;color:#102d3b;\"\u003eConnections\u003c\/th\u003e\n\u003ctd style=\"padding:12px;vertical-align:top;border-bottom:1px solid #dce8eb;\"\u003eExternal and internal threaded ends\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth scope=\"row\" style=\"padding:12px;text-align:left;vertical-align:top;border-bottom:1px solid #dce8eb;color:#102d3b;\"\u003eFinish\u003c\/th\u003e\n\u003ctd style=\"padding:12px;vertical-align:top;border-bottom:1px solid #dce8eb;\"\u003eBlack, with Dark Clear Skies branding\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr style=\"background:#eef6f7;\"\u003e\n\u003cth scope=\"row\" style=\"padding:12px;text-align:left;vertical-align:top;border-bottom:1px solid #dce8eb;color:#102d3b;\"\u003eSKU\u003c\/th\u003e\n\u003ctd style=\"padding:12px;vertical-align:top;border-bottom:1px solid #dce8eb;overflow-wrap:anywhere;\"\u003eDCS-M52-EXT-20\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003c\/tbody\u003e\n    \u003c\/table\u003e\n  \u003c\/section\u003e\n\n  \u003csection style=\"margin:0 0 28px;\"\u003e\n    \u003ch2 style=\"margin:0 0 12px;color:#102d3b;font-size:25px;line-height:1.3;\"\u003eFit gently. Check the complete assembly.\u003c\/h2\u003e\n    \u003cp style=\"margin:0 0 12px;\"\u003eConfirm the thread diameter, pitch and mating ends before fitting. Keep the components square and start each connection by hand. Stop if the threads bind; do not force a mismatched connection.\u003c\/p\u003e\n    \u003cp style=\"margin:0;\"\u003eOnce assembled, check that each joint seats correctly, confirm the spacing and refocus the telescope. Adding an extension does not guarantee that every camera or optical system will reach focus.\u003c\/p\u003e\n  \u003c\/section\u003e\n\n  \u003csection style=\"background:#eef6f7;border-radius:12px;padding:22px;box-sizing:border-box;\"\u003e\n    \u003ch2 style=\"margin:0 0 10px;color:#102d3b;font-size:22px;line-height:1.3;\"\u003eWhat’s included\u003c\/h2\u003e\n    \u003cp style=\"margin:0 0 16px;\"\u003e1 × Dark Clear Skies M52 × 0.75 threaded extension tube, with a specified 20 mm extension. Cameras and other imaging accessories are not included.\u003c\/p\u003e\n    \u003ca href=\"\/collections\/adapters-extension-tubes\" style=\"display:inline-block;background:#08717c;color:#fff;text-decoration:none;font-weight:700;font-size:15px;line-height:1.5;border-radius:7px;padding:12px 16px;max-width:100%;box-sizing:border-box;\"\u003eExplore adapters \u0026amp; extension tubes →\u003c\/a\u003e\n  \u003c\/section\u003e\n\u003c\/div\u003e","brand":"Dark Clear Skies","offers":[{"title":"Default Title","offer_id":55730171281784,"sku":"DCS-M52-EXT-20","price":19.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0523\/1650\/4241\/files\/dcs-m52-20mm-clean-hero.png?v=1794148326","url":"https:\/\/www.darkclearskies.co.uk\/products\/dark-clear-skies-m52-0-75-threaded-extension-tube-20-mm","provider":"Dark Clear Skies ","version":"1.0","type":"link"}