SV80ST DIY Focuser

thingiverse

Here are files and photos of my DIY focuser for my Stellarvue SV80ST telescope. The controller is based on [anat's Leonardo-based controller](https://www.cloudynights.com/topic/594658-pnp-focus-the-simplest-ever-arduino-focus-controller/). I used the NEMA 17HS13-0404S-PG27 motor anat referenced in his post and opted to use a belt drive. With this combination, a single motor step equates to a drawtube movement of ~3 microns. At f6, the critical focus zone (CFZ) for green is ~83 microns, giving about 26 steps within the CFZ. I chose to use Cat 6 cable to power the motor. I used the RJ45 keystone receiver published [here](https://www.thingiverse.com/thing:548145) by mwu. The focus friction screw was removed, and the reaction frame is anchored to the focuser with a countersunk M4 bolt (3mm long?). The NEMA motor is anchored in its box with M3 screws, and the box is mounted to reaction frame with M3 bolts (25-30mm long). Springs (1"x15/64"x0.28") were used to tension the belt. M3 nuts are fit into the motor holder. Lids were held in place and the Arduino Leonardo was mounted with the smallest wood screws I could find (don't have the reference information to hand).