Purchased a 10 inch Orion Dobsonian With a bad Control board and encoders
Added the Astropi Customs system
Replaced the factory dc motors/encoders with the Astropi Customs stepper motor system

Shows a 20 tooth to a 30 tooth pulley on the 6mm worm gear shaft
and the standard 9:1 reducer making a 13.5:1 or 0.00074074 deg/full step and
.0000462963 micro step