{"product_id":"m42-extension-tube-20-mm","title":"DCS M42 × 0.75 Extension Tube – 20 mm","description":"\u003cdiv class=\"dcs-product-description\" style=\"color:#172436;line-height:1.7;\"\u003e\n\u003cdiv style=\"background:#102239;color:#ffffff;padding:26px;border-radius:12px;margin-bottom:22px;\"\u003e\n\u003cp style=\"margin:0 0 8px;letter-spacing:1.5px;font-size:12px;color:#b8d5ee;\"\u003eDARK CLEAR SKIES · IMAGING ACCESSORIES\u003c\/p\u003e\n\u003ch2 style=\"margin:0 0 12px;color:#ffffff;font-size:28px;line-height:1.25;\"\u003eAdd 20 mm.\u003cbr\u003eKeep your T2 connection.\u003c\/h2\u003e\n\u003cp style=\"margin:0;color:#ecf4fc;\"\u003eA fixed M42 × 0.75 extension tube with male and female threads, for adding a defined length to a compatible imaging train.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cp\u003eThe \u003cstrong\u003eDCS M42 × 0.75 Extension Tube – 20 mm\u003c\/strong\u003e adds \u003cstrong\u003e20 mm of specified back-focus spacing\u003c\/strong\u003e between compatible T2-threaded components. It is a practical spacer when your camera and accessories need additional separation to meet the spacing requirement of an optical corrector, reducer or flattener.\u003c\/p\u003e\n\u003cfigure style=\"margin:22px 0;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0523\/1650\/4241\/files\/dcs-m42-20mm-extension-tube-studio-front.png?v=1794161084\" alt=\"DCS M42 x 0.75 20 mm extension tube showing the female thread and Dark Clear Skies engraving\" width=\"1254\" height=\"1254\" style=\"display:block;width:100%;max-width:560px;height:auto;margin:auto;border-radius:10px;\"\u003e\u003cfigcaption style=\"text-align:center;font-size:13px;color:#516174;margin-top:8px;\"\u003eThe DCS-branded tube, viewed from the female-threaded end.\u003c\/figcaption\u003e\u003c\/figure\u003e\n\u003cdiv style=\"background:#f0f6fb;border-left:4px solid #377fae;padding:18px 20px;margin:22px 0;\"\u003e\n\u003ch3 style=\"margin:0 0 10px;font-size:19px;\"\u003eThree details to match\u003c\/h3\u003e\n\u003cul style=\"margin:0;padding-left:20px;\"\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread:\u003c\/strong\u003e M42 × 0.75, also known as T2.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConnections:\u003c\/strong\u003e male at one end and female at the other.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAdded spacing:\u003c\/strong\u003e 20 mm.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003ch2\u003ePlan the spacing in your imaging train\u003c\/h2\u003e\n\u003cp\u003eCamera sensor distance, filter wheels, off-axis guiders and adapters all contribute to the distance behind an optical corrector. This fixed-length tube provides a 20 mm section within that assembly while retaining the same T2 thread size.\u003c\/p\u003e\n\u003cp\u003eCheck the spacing specified for your exact optical accessory, then account for the components already installed. The 20 mm figure is the tube’s specified back-focus contribution, as stated on its product label; use that figure when planning the spacing between the mating components.\u003c\/p\u003e\n\u003ch2\u003eCompatibility and fitting\u003c\/h2\u003e\n\u003cp\u003eThe \u003cstrong\u003eM42 × 0.75 male end\u003c\/strong\u003e screws into a matching T2 female connection, while the \u003cstrong\u003eM42 × 0.75 female end\u003c\/strong\u003e accepts a matching T2 male connection. Check both the diameter and pitch on the parts you are joining.\u003c\/p\u003e\n\u003cp\u003eUse matching 0.75 mm-pitch components. Photographic M42 × 1 connections use a different pitch and require a suitable adapter, as do M48 or M54 connections. Check available thread clearance and the total spacing of your assembly before use.\u003c\/p\u003e\n\u003cfigure style=\"margin:22px 0;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0523\/1650\/4241\/files\/dcs-m42-20mm-extension-tube-studio-male-thread.png?v=1794161097\" alt=\"DCS M42 x 0.75 20 mm extension tube showing the external male thread and open bore\" width=\"1254\" height=\"1254\" loading=\"lazy\" style=\"display:block;width:100%;max-width:560px;height:auto;margin:auto;border-radius:10px;\"\u003e\u003cfigcaption style=\"text-align:center;font-size:13px;color:#516174;margin-top:8px;\"\u003eThe external male thread at the opposite end of the tube.\u003c\/figcaption\u003e\u003c\/figure\u003e\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003ctable style=\"width:100%;border-collapse:collapse;margin:14px 0 22px;\"\u003e\u003ctbody\u003e\n\u003ctr style=\"background:#edf3f8;\"\u003e\n\u003cth scope=\"row\" style=\"text-align:left;padding:12px;border-bottom:1px solid #dce5ed;\"\u003eBrand\u003c\/th\u003e\n\u003ctd style=\"padding:12px;border-bottom:1px solid #dce5ed;\"\u003eDark Clear Skies\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\" style=\"text-align:left;padding:12px;border-bottom:1px solid #dce5ed;\"\u003eProduct type\u003c\/th\u003e\n\u003ctd style=\"padding:12px;border-bottom:1px solid #dce5ed;\"\u003eFixed threaded extension tube\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#edf3f8;\"\u003e\n\u003cth scope=\"row\" style=\"text-align:left;padding:12px;border-bottom:1px solid #dce5ed;\"\u003eExternal connection\u003c\/th\u003e\n\u003ctd style=\"padding:12px;border-bottom:1px solid #dce5ed;\"\u003eM42 × 0.75 male (T2)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\" style=\"text-align:left;padding:12px;border-bottom:1px solid #dce5ed;\"\u003eInternal connection\u003c\/th\u003e\n\u003ctd style=\"padding:12px;border-bottom:1px solid #dce5ed;\"\u003eM42 × 0.75 female (T2)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#edf3f8;\"\u003e\n\u003cth scope=\"row\" style=\"text-align:left;padding:12px;border-bottom:1px solid #dce5ed;\"\u003eSpecified back-focus spacing\u003c\/th\u003e\n\u003ctd style=\"padding:12px;border-bottom:1px solid #dce5ed;\"\u003e20 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\" style=\"text-align:left;padding:12px;border-bottom:1px solid #dce5ed;\"\u003eFinish\u003c\/th\u003e\n\u003ctd style=\"padding:12px;border-bottom:1px solid #dce5ed;\"\u003eBlack, with Dark Clear Skies engraving\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#edf3f8;\"\u003e\n\u003cth scope=\"row\" style=\"text-align:left;padding:12px;border-bottom:1px solid #dce5ed;\"\u003eSKU\u003c\/th\u003e\n\u003ctd style=\"padding:12px;border-bottom:1px solid #dce5ed;\"\u003eDCS-M42-EXT-20\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\n\u003ch2\u003eWhat’s included\u003c\/h2\u003e\n\u003cp\u003eOne DCS M42 × 0.75 extension tube with 20 mm specified back-focus spacing. Cameras, optical correctors and additional adapters are sold separately.\u003c\/p\u003e\n\u003ch2\u003eChoosing your extension\u003c\/h2\u003e\n\u003cp\u003eBrowse our \u003ca href=\"\/collections\/telescope-adapters-extension-tubes\"\u003etelescope adapters and extension tubes\u003c\/a\u003e for other connections and lengths. If you need help matching a spacer, tell us the exact components you are connecting and the back-focus distance you need to achieve.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Dark Clear Skies","offers":[{"title":"Default Title","offer_id":55730422808952,"sku":"DCS-M42-EXT-20","price":12.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0523\/1650\/4241\/files\/dcs-m42-20mm-extension-tube-studio-front.png?v=1794161084","url":"https:\/\/www.darkclearskies.co.uk\/products\/m42-extension-tube-20-mm","provider":"Dark Clear Skies ","version":"1.0","type":"link"}