Focussing failed last night at 01:34:43 with messages "Auto focus failed, moving back to initial focus position 24,477" and "Linear Autofocus algorithm aborted". I woke up and checked at 06.00 and found job still running with a very long XXXX focusing operation running. Clicking on this operation the information given was Focus successful, on-going, After Filter Change. Here's my settings:



I tried to screen grab to show V curve and image but Kstars crashed as there was no connection so here is a description. The V curve looked good apart from 9th and 10th captures which had very low HFR value of 1! Out of focus star images with RC telescopes look like small donuts. The red annotations on the 10th image indicated these stars had not been detected but other ones had but there was no star image of any merit at these points? I think I have seen if star really gets out of focus stars can be detected from knots in the doughnut rings. I don't think this happened here however.

What is the best detection algorithm and setting for RC telescopes?
The job should have failed and telescope parked and not continued indefinitely. Was set to sequence completion.

As seen from he image above taken after restored power to devices and Raspberry Pi, the focus module is showing the focuser at position 24477!

[2022-09-01T01:34:43.756 GMT Summer Time WARN ][ org.kde.kstars.ekos.capture] - "{Device: ZWO CCD ASI2600MM Pro Property: CCD1 Element: CCD1 Chip: 0}" Ignoring Received FITS as it has the wrong capture mode 1
[2022-09-01T01:34:43.914 GMT Summer Time INFO ][ org.kde.kstars.ekos.focus] - "Image received."
[2022-09-01T01:34:43.915 GMT Summer Time INFO ][ org.kde.kstars.ekos.focus] - "Detecting sources..."
[2022-09-01T01:34:44.189 GMT Summer Time INFO ][ org.kde.kstars.ekos.focus] - "Detection complete."
[2022-09-01T01:34:44.284 GMT Summer Time WARN ][ org.kde.kstars.ekos.focus] - Focus GSL error: invalid argument supplied by user
[2022-09-01T01:34:44.284 GMT Summer Time WARN ][ org.kde.kstars.ekos.focus] - Focus GSL error: invalid argument supplied by user
[2022-09-01T01:34:44.288 GMT Summer Time INFO ][ org.kde.kstars.ekos.focus] - "Linear autofocus algorithm aborted."
[2022-09-01T01:34:44.288 GMT Summer Time INFO ][ org.kde.kstars.ekos.focus] - "Autofocus failed, moving back to initial focus position 24,477."
[2022-09-01T01:34:44.498 GMT Summer Time INFO ][ org.kde.kstars.indi] - ASI EAF : "[INFO] Focuser is moving to position 24477 "

Hi David,

I had a quick look at the enclosed log. Looks like focus failed to find any stars and aborted, which could, of course, be reasonable. Did you post the correct image? (I can't see anything on the v-curve that you refer to.)

Guiding and Observatory look to have continued for a few hours after Focus aborted.

I see you are using Quadratic as the Curve Fit. If you changed this to Parabola you should get the same curve fit but on more recent code so I would suggest trying this.

I don't have an RC so I can't suggest anything for the best detection algorithm. You could experiment yourself, of course.

Here is an enlarged portion of out of focus image. Further out of focus star images turn into distinct rings.

Thanks for response to topic #86260 - Following that one so can close this one.