In the New Year I’m hoping to make the Arduino stepper motor focuser ( https://sourceforge.net/projects/arduinofocuscontrollerpro/).
The pdf instructions raise the issue of backlash in an SCT focus knob. Two solutions are given, add a Crayford focuser or use FocusMax which only focuses in one direction. I’m set on using SGPro and I don’t really want to spend money on a Crayford.
Does SGPro work the same way as FocusMax (i.e. focus in one direction only)?
Actually I don’t understand how FocusMax works in one direction only. It seems to produce a V-curve to find the optimum focus point (as SGPro does) so presumably it will have to wind back to the best position after producing the curve, thus encountering backlash.