[torsion (Bram)]

Hi,

Would anyone know the distance the primary mirror travels per turn of the focus knob on the back of a Celestron Edge HD scope?

This would be the pitch of the focus screw, I would assume. Next step will be to take off the rubber nob and see if I can make the screw stick out to measure the pitch.

I am in the process of installing a motorised focusser and need to select a stepper motor. Just wondering if I can get a straight one or one with gears (few or lots).

Thanks in advanced.
cheers,
Bram