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INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

Imaging during partly cloudy nights

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Wolfgang,

Yes, I use darks when using the internal guider. Maybe I eliminate the gain setting. I've purchased a new guide camera (ASI290) to replace my ASI120. I'm beginning to suspect that the camera is part of the problem.

I've always used PHD2 until a couple of weeks ago. I suspected that I was having communication problems between PHD2 and EKOS, which was causing some guiding problems. Since moving to the internal guider, my results are much better.

Thank you,

1st Ron
2 years 7 months ago #74768

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     The main difference is that I am using PHD2 for guiding while you are using the internal guider. In PHD2 I can set the minimum star FWHM so that I can avoid quite good taking hot pixels.

FWIW, if you use SEP MultiStar guiding, then StellarSolver is the star detection method, and StellarSolver has parameters to adjust for minimum star size. In fact, I'd expect that the defaults would do that.

Hy
 
2 years 7 months ago #74771

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Yes, it's set to default. Perhaps I'll try mid-sized starts.

Thanks,

Ron
2 years 7 months ago #74774

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So back to this, with particular questions about PHD2.

Since starting to use the scheduler with repeated ~1-hour jobs set to re-try on failure, I have had a few partly cloudy nights but never yet had PHD2 act in a way that triggered the sequence job to abort/restart. Instead, capture aborts (because guiding is out of limits), PHD2 continues to "guide" even though it can see only a few, if any, stars. When the cloud passes by and guiding gets back within limits, capture restarts. That is fine, except I think the point of abort/restart is to allow a re-alignment to deal with the mount drifting off target during the cloudy break.
Is there a PHD2 setting I should be looking for to help trigger the scheduler to abort the job?

Last night I had a particularly vexing PHD2 behavior with clouds. The early part of the night had several episodes of cloudy crummy guiding, but I was getting enough successful 4-minute exposures to keep going. Tried to get some sleep. Woke up to discover this:
 
The guide camera view showed that there were not currently clouds, but the guide star had a huge HFR. I guess it latched onto a really bright star when that was what was visible, and never let go. I stopped and restarted guiding, and it turned into this:
 

If I had not woken up and checked, I assume it would have continued trying to guide on that same bright star.
2 years 6 months ago #75334
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Interesting, this case is not considered, where guiding continues although it constantly creates high guiding deviations. The explanation for the behavior you were experiencing is, that only capturing aborts, but it does not subsequently stop guiding.

When capture aborts and the scheduler is configured to restart aborted jobs, it restarts guiding if necessary and then starts capturing again. Since guiding is still running, the scheduler leaves it running and restarts only capturing.

The question indeed is, if we should stop guiding as well wenn capturing is aborted due to guiding deviations.

Regarding re-alignment: there is an option to trigger this. I personally do not use it, since I never had the case that the mount was awfully off after clouds passing by. But on the other hand, my mount sometimes has problems when I try to align too often to the same spot. That's why I do not use this option.
2 years 6 months ago #75336

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I've had the exact same issue. I thought when guiding lost the stars, it would stop capture and attempt to restart guiding. If it failed a certain amount of times, it would abort the job and behave according to the scheduler's instructions for restarting the job.

The way it works now, I never get an aborted job... so what's the point of schedule instructions? So when it finally starts capturing again, I'm not on the object any longer because of drift. The realignment step is very important to my process.

Thanks,

Ron
2 years 6 months ago #75357

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As soon as guiding itself aborts, it behaves exactly as you describe. Here we had the case that guiding continued, i.e. there where stars still visible enough that it could guide, but with significant deviations.
2 years 6 months ago #75359

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I recently had the problem where it clouds over and guiding locks onto a hot pixel. I haven't been able to get darks working properly yet - this is something I need to do. So what then happens is guiding fights tracking and the target drifts away. When the clouds pass and stars re-appear, guiding clamps onto a real star and everything continues except the target is no longer framed. Looking at the comment from @Hy above it seems the SEP profile = 1-Guide-Default has a star filtering parameter Min Size set to 0 px. I think I might try setting this to 2 (as per the medium stars profile). Since the default profile seems to work well for me and has several different parameters to the medium stars profile, I think this would be better than changing profiles.

I see there is an option "Restart Alignment on Guiding Calibration Failure" under Ekos -> Scheduler. Is this the option referred to (or is there another option I can't find)? Would guiding do a calibration after failing (I have the "Store and reuse guide calibration when possible" option set? 
 
2 years 6 months ago #75363

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Wolfgang,

That is not how mine works... it never aborts the job. I had a couple of hours of failed guiding with aborted capture, but the sequence never aborted... so no re-alignment.

Ron
2 years 6 months ago #75376

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Hm, that's strange. Could you please post the log of such an example?
2 years 6 months ago #75378

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Wolfgang,

I posted the log earlier in the thread. As was discussed earlier, it might have found a hot pixel... but I was using darks. It's been difficult over the last few weeks to test because of lack of clear skies.

I'm currently traveling, but will try again once I get a clear night.

Ron
2 years 6 months ago #75380

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Hi John,
when guiding fails, the restart of guiding normally re-uses the calibration, no matter whether "Store and reuse guide calibration..." is selected. With this option selected, the calibration is stored and will be reused the next time KStars is started.

The option you might search is one above the "Restart Alignment on Guiding Calibration Failure" - its "Force re-alignment before starting each job.
2 years 6 months ago #75389

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