ZWO EAF to GSO Focusser Adapter

thingiverse

This little widget allows for a much cleaner connection from the ZWO Electronic Automatic Focusser to GSO focussers (found on cheap Ritchey Chretien (RC) telescopes). The way the instructions are written you would attach to the slow-motion control for the focusser which is not ideal. The metal rod is very thin as well which would ruin the coaxial joint needed for smooth motion. I found removing both the slow and fast knobs and designing this widget to connect to the bearing underneath the fast focus knob gave a much cleaner and more robust joint. The setup without the adapter is shown in the second image. I used the middle hole to connect the plate to the focusser as this doesn't need a precise tension. The hole closest to the telescope proper I replaced with a grub screw. This one controls the focus tension. The hole closest to the eyepiece end is the focus lock but must be attached for the focusser to function. For this I used a longish cap-head bolt. The metal plate doesn't rest on the screw head, I used a couple of washers either side to give a bit more clamping surface area. 2021-03-09 - Updated the file, v14 can use an M3 bolt and nut to get a better grip on the motor. Works much better!