Autofocus setup

Hi everyone,
I can’t get the autofocus to work properly, it always gets it wrong.
Could someone explain to me what the complete setup procedure is like?
My setup is this:
ZWO focuser
QHY294M camera
ZWO filter wheel
Thank you

This is explained in detail in the SGPro Documentation (PDF), , pp. 132 - 147.


Thank you!

I tried in all ways following the instructions but nothing to do can not focus correctly … what can I do?

Attach some screenshots of your auto focus runs and I’ll take a look and see what might need adjusting.


He calculates 1847 but instead the correct value would be 1878.

Where am I wrong?

Why do you say the correct value is at 1878? The minimum HFR indicates the best focus point, which clearly is at 1847. There is no error in this AF sequence, it works as it should.

However, you are going too wide. You can reduce the step size to get more points around the minimum. Maybe try a step size of 20.

Also, the “wing” to the right indicates that you should increase your backlash setting.

I know because I did the focusing with the bhatinov mask.
at 1847 the star spikes are doubled.
at 1878 they are perfect.
So there is clearly a problem here.
“Also, the “wing” to the right indicates that you should increase your backlash setting”
How should I do?
Thank you

If the backlash is large, then you focuser step value is not reliable anymore, making it hard to compare measurements at different positions. This might explain the difference with the mask.

You can set backlash compensation in the control module, see “Other button” here: Focusers

I have mine at 300 steps. You will gave to test different values.

Are these screenshots good to understand the problem? Thank you