Focuser Mount for Skywatcher Telescopes

The adjustment screws stay accessible with this design. I also accounted for the curvature of the original screw cover. The curvature near the axis allows for 3d printed shaft couplers with longer screws.

The center distance is 54mm

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BOM required:

1x Nema17

4x M3x16mm (shorter might work, too, but it is untested)

4x M3x8mm

1x Shaft Coupler 4mmx5mm, L25mm (example: https://aliexpress.com/item/1005001538408571.html)

1x Shaft Ø5x~30mm (I used a 5mm brass rod and cut it to length; example: https://aliexpress.com/item/1005009272942522)

1x Small GT2 Pulley 5mm bore

1x Large GT2 Pulley 5mm bore

1x GT2 Belt ( Center Distance is 54mm; use this calculator: https://www.wantabelt.de/en/timing-belt/calculation-program/belt-length-calculator-for-timing-belts-2)

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For the OnStep configuration:

Steps per micron = [Motor steps] x [Driver microsteps] x [Gear ratio] x [Knob turns needed for max distance] / [Max motion distance in microns]

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For 3d printed couplers and pulleys, check out:

https://www.printables.com/model/165030-elektronic-focuser-for-newton-or-refractor-with-2-

and

https://www.printables.com/model/333720-gt2-pulley-the-big-collection-updated