So rather than attempt to rob focus the borg focuser for the time being I have decided to robo focus the 1:1 focuser on the Pentax (no 10:1 knob here on the focuser!). This presents it's own issues - namely static torque and accuracy. I'm thinking that a bipolar stepper motor with a 100:1 gear box (with backlash) that can move over 32Kg/cm would have enough torque for the 1:1 focuser with a mass of AP equipment attached. Also if the stepper motor is running at a 1.8 degree step, the backlas