Motorising a Skymax 180 Focuser

[johninderby]

 

Motorising a Skymax 180 Focuser

Fitting a Skywatcher Autofocuser turned out to be a simpler job than expected. 

Printed a finder dovetail out but doubled the length from standard. Then took one of the mounting bases than came with the focuser unit and flattened the main part of it in a vice so that it would sit flat on top of the dovetail. Drilled an extra mounting hole and countersunk the hole so the bolt heads wouldn’t protrude.

Now I had the motor unit ready to fit into a standard Synta type finder shoe.I added an extra mounting shoe to the existing mounting holes in the scope. Originaly intended so you can fit the finder in another postion.

Used GT2 toothed drive pulleys. 20t for the motor and 40t for the focuser knob which gives a 2:1 ratio. The 20t pulley had a 5mm bore that needed drilling out to 6mm to fit the motor shaft. The 40t pulley had a 12mm bore that needed drilling out to 13mm then a bit of filling to enlarge the the bore to 13.15mm.  Had an old AstroEngineering badge that was just the right size to fit the pulley and cover the big hole in the pulley. Not really necessary but looks neater.

Temporarily using a 280mm drive belt as that was readily   available. A 270mm is on it’s way but takes a few days to arrive. Runs very smoothly and is easily removable and the drive pulley makes a nice focuser knob.

Edited August 11, 2019 by johninderby

[RobW]

This thread was super helpful, many thanks for this.

My version came out very similar - slight difference in the syntax mount and managed so far to use a standard 280mm belt:

https://www.cloudynights.com/gallery/album/24645-skymax-180/