Exposure flapping

[illigtr]

Since I turned on auto-gain with the October 2025 release, I have noticed some serious exposure flapping. Here is my 24 hour graph. Note the variance of 5 seconds on exposures at the beginning and end of night mode. Also, for some apparent reason, also happening during the night.

How can I zero in on the parameters causing this issue, since auto-gain has been turned on?

[aaronwmorris]

Is there any way I could view the timelapse associated with this graph?

[illigtr]

Sure, this link should work.

[aaronwmorris]

That is most definitely exposure flapping. :-) Not that I doubted it.

Can you also post your Support Info?

[illigtr]

Sure.
indi-allsky_support_info_20251227_202230.txt.gz

Note that once this started, I turned off auto-gain. My night ADU deviation was 5 and my day was 10 (working for months, no issues). Once the flapping began, I tried to mitigate by putting the settings back to default night 10 / day 20. Auto-gain is off for now.

[aaronwmorris]

I do not understand the flapping at dawn and dusk. The brightness increases do not "feel" like it would correspond to the values in the display. I would normally think that maybe the AWB algorithm is enabled, but the settings say it is disabled.

The flapping in the middle of the night looks more normal. I thought I had mitigated the flapping in a previous change, but maybe something else is going on. The exceptions that are showing in the Support Info might be a clue. An exception is being generated in the moon overlay.

I merged #2586 which includes some commented log statements to help debug this. If you want, you could upgrade to this and un-comment the log statement on line 139 in indi_allsky/moonOverlay.py

And, this might not be related at all.

[illigtr]

I don't believe there is any historical record of changes made in config, is there? Potentially, a background dump config on any changes prior to reload would be an interesting feature. The resulting files could be compared and changes dumped.

[illigtr]

OK. I'll do the upgrade and uncomment the additional logging. I will also more methodically download a support file after each config change while testing, so they correspond to each nightly time-lapse.

[illigtr]

I have some additional data for you based on last night.
Note that I turned on auto-gain at 18:30 EST.
Here is the new support info taken after the change and after a clean restart of services.

indi-allsky_support_info_2025-12-28.txt.gz

My exposure graph (24h) looks like this

Here is the timelapse

I pulled the log file download here:

indi-allsky_log_20251229_122234.txt.gz

Let me know what other info you need.

[illigtr]

Second night. No changes to settings.

Support Info:
indi-allsky_support_info_20251230_83842.txt.gz

[ldb20151]

For what it’s worth I’m seeing the same exposure flapping. It also started when I enabled Exposure Priority Gain Mode to auto. I’ve not really had time to troubleshoot it but my symptoms sound very similar. I have also noticed the flapping happens on nights or days where the seeing conditions are pretty bad. Once I finish tuning I’ll likely adjust these bad seeing out of collects. Will be watching this topic. If more data would help I’m happy to send.
v/r
Larry

[aaronwmorris]

I am assuming this is on your Pi HQ Camera?

[ldb20151]

Yes— both cameras using pi5, 8gb with pi hq cameras.

[aaronwmorris]

Are you just using the default interface for these? Not using indi_libcamera_ccd or indi_pylibcamera?

[ldb20151]

That’s correct—same default libcamera interface that setup installs. It has usually worked well.

[illigtr]

@aaronwmorris I have a Pi HQ camera on a Pi5 8GB, but I am using indi-pylibcamera.