
Description
When your Newtonian’s stock focuser starts to feel like the weak link—especially with a heavier camera train—this Starfield Optics 2" rack-and-pinion upgrade is built to add rigidity, repeatability, and fine control. The R&P drive gives a more positive, “geared” feel than many friction-based designs, and the dual-speed controls make it easy to land on tight focus without hunting.
Geared focusing designed for heavier payloads
Rack-and-pinion focusers are often chosen when you’re hanging more weight off the back of a Newtonian and want a focusing system that stays consistent through the night.
Dual-speed focusing (coarse + 10:1 fine)
Dial in focus quickly with the main knob, then “creep” into perfect focus using the microfocus control. A drawtube lock is included for holding position once you’ve set focus.
50 mm of travel + drawtube scale
You get about 50 mm (~2") of drawtube travel and a laser-marked scale to help you return to known focus positions.
ZWO EAF mounting made straightforward
This version is listed as EAF compatible out of the box, using the standard EAF bracket, and includes a coupler (noting it’s 5 mm and may need adjustment depending on EAF generation).
Included / features
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2" focuser body with dual-speed knobs
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2" compression ring eyepiece holder + 2" to 1.25" adapter (with filter threads on the adapter)
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1.25" dust plug
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Ships in a foam-fitted padded box; no manual, and mounting screws for the base plate are not included
Quick specs
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Min height (no 1.25" adapter): 79.0 mm (drawtube may extend ~32 mm below the curved plate at minimum height)
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Max height (no 1.25" adapter): 129.0 mm
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Travel: 50 mm
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Drawtube OD: 59 mm (tube cutout must exceed this)
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Weight (with 1.25" adapter): 860 g
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Max body OD: 82 mm
2” Newtonian focuser is a direct bolt-on replacement for stock rack-and-pinion focusers on 8" and 10" GSO Dobsonian telescopes sold under various brand names. Direct bolt-on compatibility also applies to Celestron Star Hopper and Meade Light Bridge telescopes. EAF motor focuser compatible.
Base Plate Dimensions and Mounting Data
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Curve diameter: 9.06" (230mm) Base plate dimensions: 3.54" x 3.54" (90mm x 90mm)
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Hole spacing parallel to telescope tube / optical axis, center-to-center: 70mm (2.76")
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Hole spacing perpendicular to telescope tube, center-to-center, straight-line measurement: 73mm (2.87")
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Hole spacing perpendicular to telescope tube, center-to-center, measured along base plate curve: 74mm (2.91")
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Central opening inside diameter: 3.07" (77.9mm)