Autofocus overshooting step size?

Sequence Generator Auto Focus
1

Hey guys, I have been using autofocus with my USB Focus focuser with flawless results for the past 12 months. I’m running a step size of 80, and 7 autofocus points. 90% of the time I get a great V curve, and all my subs are great.

Here’s the problem…all of a sudden when I run the routine, my graph shows 2 points, sometimes 1! On the right hand side (focused out position) then the rest of the 5 points end up on the other side of the graph, producing a “tick” shaped graph, with the starts grossly out of focus. I have tried changing step size and aoutofocus points, star detection thresh hold, but nothing successful.

Not sure how to approach this next?

Any help would be nicely appreciated.
Erik

2

Sounds like you weren’t in focus to begin with or that your focus shifted between auto focus runs. SGP should detect this if it’s bad enough and recenter the auto focus attempt and run again. Assuming Smart Focus is enabled.

Thanks,
Jared

3

Hi Jared, I thought so too at first, but ch code focus with my mask and it
was spot on before running. I’m also thinking maybe some backlash has
developed in the focuser.

Erik

4

Got it sorted. I dropped ,y step size back to 65, 9 data points, and used 2x2 binning. Don’t know why it had an issue now after so long, but got a spot on v curve!

Erik