[avandonk]

With the new Gemini II coming out for Losmandy mounts I will keep an eye out for an older well loved Titan Mount.

I would then replace the servos and gearboxes with harmonic drives. These have encoded servos and with a 100:1 harmonic drive the number of encoder pulses or resolution is 800,000 per rev of the output shaft. This corresponds to 800,000 per single worm turn which is 1.333r degrees of mount movement. This is 21.6 million for a full 360 degrees of mount movement.

Of course a stepper motor could be used with a harmonic drive or 'gearbox' and with a ratio of 100:1 a 200step motor would have 20,000 steps per worm rev before microstepping.

Harmonic drives have no backlash. They do have a small PE but that would disappear when divided by the worm ratio.

There is no 'correct' solution for drives and mounts. It is only the best that is affordable to us amateurs. Advances in drive technology and computers puts previously undreamt of precision within reach.

Bert