SV80ST DIY Focuser

thingiverse

Here are files and photos of my do-it-yourself focuser for my Stellarvue SV80ST telescope. The controller is based on anat's Leonardo-based controller, found here: https://www.cloudynights.com/topic/594658-pnp-focus-the-simplest-ever-arduino-focus-controller/. I used the NEMA 17HS13-0404S-PG27 motor that anat referenced in his post and decided to use a belt drive. With this combination, a single motor step equals a drawtube movement of about 3 microns. At f6, the critical focus zone (CFZ) for green is approximately 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 the reaction frame with M3 bolts (25-30mm long). Springs were used to tension the belt. M3 nuts fit into the motor holder. Lids were held in place, and the Arduino Leonardo was mounted using the smallest wood screws I could find.