{"product_id":"starfield-optics-3-newtonian-focuser-rack-and-pinion","title":"Starfield Optics 3\" Newtonian Focuser Rack and Pinion","description":"\u003cp data-start=\"92\" data-end=\"597\"\u003eIf your Newtonian is carrying a coma corrector, filter wheel, and a full-size camera, the focuser becomes a structural part of the imaging train—not just a convenience. This \u003cstrong data-start=\"266\" data-end=\"288\"\u003e3\" rack-and-pinion\u003c\/strong\u003e unit is built for that role: a large clear aperture, a rigid drawtube support system, and a geared drive that keeps focus repeatable even when the payload is substantial. It’s a strong choice for fast Newtonians and imaging builds that have outgrown typical 2\" focusers. \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003chr data-start=\"599\" data-end=\"602\"\u003e\n\u003ch3 data-section-id=\"f48nwg\" data-start=\"604\" data-end=\"641\"\u003eWhat you get (and why it matters)\u003c\/h3\u003e\n\u003cp data-start=\"643\" data-end=\"1042\"\u003e\u003cstrong data-start=\"643\" data-end=\"703\"\u003eGeared rack-and-pinion drive with “no-surprise” movement\u003c\/strong\u003e\u003cbr data-start=\"703\" data-end=\"706\"\u003eThe drawtube rides on a bearing system while the motion is driven by a \u003cstrong data-start=\"777\" data-end=\"795\"\u003ehelical pinion\u003c\/strong\u003e. That separation between support and adjustment is specifically intended to keep the drawtube from shifting under load—useful for maintaining collimation and field sharpness as your camera train gets heavier. \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp data-start=\"1044\" data-end=\"1274\"\u003e\u003cstrong data-start=\"1044\" data-end=\"1086\"\u003eDual-speed focusing for critical stars\u003c\/strong\u003e\u003cbr data-start=\"1086\" data-end=\"1089\"\u003eA \u003cstrong data-start=\"1091\" data-end=\"1115\"\u003e10:1 micro-reduction\u003c\/strong\u003e lets you sneak up on perfect focus without overshoot—especially handy at f\/4–f\/5 where the critical focus zone is tight. \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp data-start=\"1478\" data-end=\"1848\"\u003e\u003cstrong data-start=\"1478\" data-end=\"1507\"\u003eEAF-ready motor interface\u003c\/strong\u003e\u003cbr data-start=\"1507\" data-end=\"1510\"\u003eThis focuser provides a \u003cstrong data-start=\"1534\" data-end=\"1574\"\u003e34 mm shaft diameter motor interface\u003c\/strong\u003e on the focuser side, making it well-suited for adding an electronic focuser motor (such as a ZWO EAF) using an appropriate bracket\/coupler solution. The ZWO EAF system is designed to mount to a wide range of focusers via a bracket kit. \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003chr data-start=\"1850\" data-end=\"1853\"\u003e\n\u003ch3 data-section-id=\"12z5ss1\" data-start=\"1855\" data-end=\"1885\"\u003eFitment notes (Newtonians)\u003c\/h3\u003e\n\u003cul data-start=\"1887\" data-end=\"2156\"\u003e\n\u003cli data-section-id=\"1wcx5fb\" data-start=\"1887\" data-end=\"2037\"\u003e\n\u003cp data-start=\"1889\" data-end=\"2037\"\u003eDesigned as a \u003cstrong data-start=\"1903\" data-end=\"1924\"\u003eNewtonian focuser\u003c\/strong\u003e with a flexible base intended for tubes \u003cstrong data-start=\"1965\" data-end=\"1996\"\u003e~225 mm diameter and larger\u003c\/strong\u003e. \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-section-id=\"k1d04\" data-start=\"2038\" data-end=\"2156\"\u003e\n\u003cp data-start=\"2040\" data-end=\"2156\"\u003eRequires a tube cutout sized for a 3\" class drawtube\/light path (see specs). \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr data-start=\"2158\" data-end=\"2161\"\u003e\n\u003ch3 data-section-id=\"ab7fh7\" data-start=\"2163\" data-end=\"2187\"\u003eIncluded connections\u003c\/h3\u003e\n\u003cul data-start=\"2189\" data-end=\"2657\"\u003e\n\u003cli data-section-id=\"p2e9nv\" data-start=\"2189\" data-end=\"2279\"\u003e\n\u003cp data-start=\"2191\" data-end=\"2279\"\u003e\u003cstrong data-start=\"2191\" data-end=\"2209\"\u003eEyepiece side:\u003c\/strong\u003e 2\" + 1.25\" (compression ring) \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-section-id=\"qet9is\" data-start=\"2280\" data-end=\"2504\"\u003e\n\u003cp data-start=\"2282\" data-end=\"2504\"\u003e\u003cstrong data-start=\"2282\" data-end=\"2316\"\u003eImaging \/ thread side options:\u003c\/strong\u003e internal \u003cstrong data-start=\"2326\" data-end=\"2343\"\u003eM78x1 \/ M68x1\u003c\/strong\u003e (female) and \u003cstrong data-start=\"2357\" data-end=\"2366\"\u003eM74x1\u003c\/strong\u003e (male) threads are provided to build a fully threaded imaging train (useful with M68 correctors). \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-section-id=\"m6wu36\" data-start=\"2505\" data-end=\"2657\"\u003e\n\u003cp data-start=\"2507\" data-end=\"2657\"\u003e\u003cstrong data-start=\"2507\" data-end=\"2520\"\u003eAdapters:\u003c\/strong\u003e 2\" and 1.25\" adapters with compression rings; the 1.25\" adapter includes a \u003cstrong data-start=\"2596\" data-end=\"2616\"\u003e2\" filter thread\u003c\/strong\u003e.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cdiv\u003e\n\u003cspan data-canva-clipboard=\"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\"\u003e\u003c\/span\u003e\n\u003cdiv\u003e\n\u003cp\u003e\u003cspan\u003e3” Newtonian focuser is a direct bolt-on replacement for stock rack-and-pinion focusers on 12\" GSO Dobsonian telescopes sold under various brand names. Direct bolt-on compatibility also applies to \u003c\/span\u003e\u003cspan\u003eCelestron Star Hopper\u003c\/span\u003e\u003cspan\u003e and \u003c\/span\u003e\u003cspan\u003eMeade Light Bridge\u003c\/span\u003e\u003cspan\u003e telescopes. EAF motor focuser compatible.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cp\u003e\u003cspan\u003eBase Plate Dimensions and Mounting Data\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eCurve diameter: 11.93\" (303mm)\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBase plate dimensions: 3.54\" x 3.54\" (90mm x 90mm)\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eHole spacing parallel to telescope tube \/ optical axis, center-to-center: 70mm (2.76\")\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eHole spacing perpendicular to telescope tube, center-to-center, straight-line measurement: 73mm (2.87\")\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eHole spacing perpendicular to telescope tube, center-to-center, measured along base plate curve: 74mm (2.91\")\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eCentral opening inside diameter: 3.07\" (77.9mm)\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e","brand":"Starfield Optics","offers":[{"title":"Default Title","offer_id":42536761131079,"sku":"SF-F-NT3","price":459.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0648\/1631\/6487\/files\/SF-F-NT3_ed7abd81-cd33-469a-9aa9-38a6615be31c.jpg?v=1772745952","url":"https:\/\/starfieldoptics.com\/products\/starfield-optics-3-newtonian-focuser-rack-and-pinion","provider":"Starfield Optics","version":"1.0","type":"link"}