{"product_id":"starfield-optics-3-dual-speed-rack-and-pinion-focuser-for-rc-telescopes-m117","title":"Starfield Optics 3\" Dual-Speed Rack-and-Pinion Focuser for RC Telescopes (M117)","description":"\u003cp data-start=\"115\" data-end=\"728\"\u003eIf you’re running a larger RC (or similar back end that uses the \u003cstrong data-start=\"180\" data-end=\"188\"\u003eM117\u003c\/strong\u003e standard) and you want a focuser that stays put under real imaging weight, this \u003cstrong data-start=\"269\" data-end=\"291\"\u003e3\" rack-and-pinion\u003c\/strong\u003e upgrade is built for exactly that job. The key advantage of this design is that the \u003cstrong data-start=\"376\" data-end=\"433\"\u003edrawtube support and the focusing drive are separated\u003c\/strong\u003e—so the tube rides on low-friction bearing surfaces while the gear train provides the movement. The result is a focuser that remains stable with heavy cameras, filter wheels, and reducers without the “give” you can sometimes see in lighter Crayford designs. \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003chr data-start=\"730\" data-end=\"733\"\u003e\n\u003ch3 data-section-id=\"5p2je8\" data-start=\"735\" data-end=\"784\"\u003eWhy this focuser is a serious imaging upgrade\u003c\/h3\u003e\n\u003cp data-start=\"786\" data-end=\"1101\"\u003e\u003cstrong data-start=\"786\" data-end=\"827\"\u003eGeared drive with high load stability\u003c\/strong\u003e\u003cbr data-start=\"827\" data-end=\"830\"\u003eInstead of relying on friction pressure to hold position, the \u003cstrong data-start=\"892\" data-end=\"911\"\u003erack-and-pinion\u003c\/strong\u003e drive provides positive, repeatable movement and strong holding power—useful when you’re hanging a substantial imaging train off the back of the scope. \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp data-start=\"1103\" data-end=\"1309\"\u003e\u003cstrong data-start=\"1103\" data-end=\"1143\"\u003eDual-speed control (10:1 microfocus)\u003c\/strong\u003e\u003cbr data-start=\"1143\" data-end=\"1146\"\u003eFast coarse focusing gets you close, and the \u003cstrong data-start=\"1191\" data-end=\"1209\"\u003e10:1 reduction\u003c\/strong\u003e makes it easy to land on critical focus without overshooting. \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp data-start=\"1311\" data-end=\"1519\"\u003e\u003cstrong data-start=\"1311\" data-end=\"1340\"\u003eRotation for easy framing\u003c\/strong\u003e\u003cbr data-start=\"1340\" data-end=\"1343\"\u003eThe included adapter assembly supports \u003cstrong data-start=\"1382\" data-end=\"1399\"\u003efull rotation\u003c\/strong\u003e so you can square up a camera or reframe without fighting your mount orientation. \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp data-start=\"1521\" data-end=\"1784\"\u003e\u003cstrong data-start=\"1521\" data-end=\"1562\"\u003eBig clear aperture for modern sensors\u003c\/strong\u003e\u003cbr data-start=\"1562\" data-end=\"1565\"\u003eWith a large light path and a \u003cstrong data-start=\"1595\" data-end=\"1620\"\u003e3\" class focuser body\u003c\/strong\u003e, it’s designed to play nicer with larger camera formats and fast RC imaging accessories. (Exact clear-aperture figure below.) \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003chr data-start=\"1786\" data-end=\"1789\"\u003e\n\u003ch3 data-section-id=\"1a94wiq\" data-start=\"1791\" data-end=\"1815\"\u003eTelescope connection\u003c\/h3\u003e\n\u003cul data-start=\"1817\" data-end=\"2087\"\u003e\n\u003cli data-section-id=\"k1anrh\" data-start=\"1817\" data-end=\"1932\"\u003e\n\u003cp data-start=\"1819\" data-end=\"1932\"\u003e\u003cstrong data-start=\"1819\" data-end=\"1845\"\u003eTelescope side thread:\u003c\/strong\u003e \u003cstrong data-start=\"1846\" data-end=\"1854\"\u003eM117\u003c\/strong\u003e (via the included connection adapter) \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-section-id=\"yqsf3w\" data-start=\"1933\" data-end=\"2087\"\u003e\n\u003cp data-start=\"1935\" data-end=\"2087\"\u003e\u003cstrong data-start=\"1935\" data-end=\"1964\"\u003eOptional plug connection:\u003c\/strong\u003e remove the adapter to reveal a \u003cstrong data-start=\"1996\" data-end=\"2006\"\u003e105 mm\u003c\/strong\u003e plug interface for custom fits\/adaptations\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"param_tech_header\"\u003e\u003cstrong\u003eTechnical parameters\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli class=\"param_tech\"\u003ediameter of drawtube: 3\"\u003c\/li\u003e\n\u003cli class=\"param_tech\"\u003eFocusing mechanism: Rack \u0026amp; Pinion\u003c\/li\u003e\n\u003cli class=\"param_tech\"\u003eLift stroke: 45 mm\u003c\/li\u003e\n\u003cli class=\"param_tech\"\u003eMounting thread (telescope side): M117x1 (female)\u003c\/li\u003e\n\u003cli class=\"param_tech\"\u003eOutput threads: M78x1 (female), M68x1 (female), M74x1 (male)\u003c\/li\u003e\n\u003cli class=\"param_tech\"\u003eadapters included: 2\" and 1.25\"\u003c\/li\u003e\n\u003cli class=\"param_tech\"\u003eload capacity: up to 6 kg\u003c\/li\u003e\n\u003cli class=\"param_tech\"\u003eweight: 1.64 kg\u003c\/li\u003e\n\u003cli class=\"param_tech\"\u003ecompatibility with focusing motors: yes (e.g. ZWO EAF)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr data-start=\"2089\" data-end=\"2092\"\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"Starfield Optics","offers":[{"title":"Default Title","offer_id":42536759525447,"sku":"SF-F-RC3","price":459.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0648\/1631\/6487\/files\/SF-F-RC3_12133998-216b-4d23-b6c0-54bedcb3d728.jpg?v=1772746002","url":"https:\/\/starfieldoptics.com\/products\/starfield-optics-3-dual-speed-rack-and-pinion-focuser-for-rc-telescopes-m117","provider":"Starfield Optics","version":"1.0","type":"link"}