Since last few days I and my friend have some issiue with autofocus.
If we have in our FOV some bright star the autosocus is crazy.
I checked, help only change FOV without bright star. Then everything is ok.
Even decrease “Crop auto focus frames” not help.
Of course this message stops autofocus.
With old version SGP I don’t had any problems.
first setup QHY695A+APO100Q
second setup QHY8L+ED80
[04/08/20 20:56:12.938][DEBUG][Main Thread][SQ;AF;] Star detection using min star size of 3px…
[04/08/20 20:56:12.938][DEBUG][Main Thread][SQ;AF;] Star detection using max star size of 60px…
[04/08/20 20:56:13.531][DEBUG][Main Thread][SQ;AF;] Find stars took: 1596 ms…
[04/08/20 20:56:13.531][DEBUG][Main Thread][SQ;AF;] Star list contains 1 stars…
[04/08/20 20:56:13.531][DEBUG][Main Thread][SQ;AF;] Calculating HFR with sample size: 3
[04/08/20 20:56:14.261][DEBUG][Camera Thread][SQ;AF;] Auto focus HFR calculated at: 3.44
[04/08/20 20:56:15.263][ERROR][Camera Thread][SQ;AF;] Auto focus received a bad HFR value 2 times in a row! Something may be wrong! :
The AF routine could only detect 1 star in the field! And a few seconds before it actually detected 0 stars. This caused two consecutive bad HFR values, hence the abort.
I also noticed that you had two good AF runs before:
AF Run Date Time Pos HFR Temp Filter Q (min Q) Misc Target
1 04/08/20 20:31:33 12752 1.28 11.77 Ha 99% (90%) Successful
2 04/08/20 20:35:04 12723 0.9 11.21 Ha 97% (90%) Successful
For AF Run 1 you also got only 1 star for the last point in that curve, but it didn’t cause an error. But the low number of detected stars appears to be the problem when you are at the edges of the AF Run.
I don’t really know a good fix here, except to reduce the AF range by lowering the step a bit, but it looks pretty well chosen already. Maybe @Ken or @Jared could comment if the max star size parameter (60 px) could be tweaked here ?
Looks like you’re using 12 second exposures and focusing with a HA filter. My guess is this is much too low. When I’ve focused through my narrowband filters I typically need about a minute per exposure to get adequate data for auto focus. Because of this we highly recommend setting up focus offsets and using the “Adjust focus per filter” option. From there you can switch to your lum, focus and then go back to your narrowband filter while keeping focus.
Good point Jared, somehow I completely missed that a Ha filter was used here!
Still, I think something additional happend here. In AF Run 1 the best focus frame had 28 stars, then for the two left-most points there were only 4 and 1 stars detected, that’s a huge ratio. In AF Run 2 however star counts were much higher (18 to 91).
I think @calberts point above is good, the very low star count in some frames could be due to a low image contrast due to passing high clouds, combined with a too short integration time for a narrowband filter.