On Sat, Jun 12, 2021 at 11:17 PM, John Kmetz wrote:
Will adding a more precise encoder on the motor really do anything for better guiding on these mounts? This will only better tell the computer brain where the rotational axis of the motor shaft is, but will that translate to a better known position of the RA (or Dec) axis? In between motor axis and sky coordinate axis you have so many meshing surfaces. On the G11, there is motor pinion gear, gear box gear #1 outer gear, gearbox gear number #1 inner gear, gearbox gear #2, spur gear #1, spur gear #2, left and right Oldham coupler mating surfaces, and finally worm to ring gear contact. The number of contacting surfaces here is at least 7 if I am counting right.
Each gear to gear mating is going to have its own slight backlash and periodic error, though worm and ring will have the largest contribution. Even if the motor turns more precisely will that motion be transmitted proportionally to the RA axis without be absorbed by the gear slop??
Well, yes, it does matter.? (Like in my case)
Let's assume that you have a very very slight polar misalignment so that the DEC generally drifts in one direction.? And also that seeing is pretty good so the axis is not constantly correcting back and forth.? In that case, the DEC motor will give a pulse every x minutes in the same direction.? It will take up all the backlash slack and elasticity.? Eventually, the telescope will move the same amount as required for every step.
