Hi

yet another question…

More theoretical than anything..

If the focuser is dropping the mirror of an sct then doesn’t it need to use backlash compensation every time to “tighten” things up?
The C6 manual says to always focus in a counter clockwise manner which implies to me that even if you’ve made a number of clockwise turns to get focus you still want to reverse a bit. In other words it’s not just when you have a change of direction that you need backlash compensation.


NINA seems to have overshoot and backlash compensation settings I believe, is this what they handle?

Regards

Nigel

The general approach of Linear and Linear 1 Pass is to focus from "outward" to "inward". So if you have the scope pointing at the sky, the outward to inward motion is raising the mirror against gravity, which will minimise mirror slop. These algos will make sure that all the datapoints and final movement follow this approach.

So part of configuring the focuser is setting it up to perform like this (getting the clockwise/anticlockwise motion sorted out).

Iterative and Polynomial don't work like this.

ok that’s sort of what I would expect, but where is this configuration?

I’ve got a Celestron focuser and given that Celestron are quite well known for sct’s I would sort of expect to be able to do that but it’s not obvious to me.

Do refractors focus is the same way ie against gravity or don’t they care?