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INDI Library v1.8.1 Released (09 Sep 2019)

Monthly maintenance release INDI v1.8.1

Wrong gain in FITS header.

3 weeks 3 hours ago
freiform
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Wrong gain in FITS header. #45237
Hi,

last night I used the scheduler for the first time. I created a sequence fir IC434 consisting of various narrowband captures and used that sequence in the scheduler. everything worked flawlessly, but the FITS headers of my images show a gain of 335 (which I use for auto-focusing) instead of the 200 I configured for the light-frames. Looking at the esq-file, it says
<OneNumber name='Gain'>200</OneNumber>
for all entries of the sequence.

This looks like a bug, or am I doing something wrong?

Sven

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3 weeks 2 hours ago
hy
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Wrong gain in FITS header. #45240
I fixed a bug on Oct 5, where the previously the capture gain was set at the start of a sequence only (not for each capture).
So, if there was an autofocus done in the middle of the sequence with a different gain, it might have used that autofocus gain for the exposure.
So, if (a) you're using code from before Oct 5, and (b) you had an autofocus triggered mid-sequence, it's likely this. Let me know.

FYI, if you want to look into it, you can look at the Indi Control panel for your camera while imaging and see which gain is actually being used.
Hy

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3 weeks 1 hour ago
freiform
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Wrong gain in FITS header. #45241
Hi Hy, my sequence contained three filter changes with AF after each change. I use 3.3.6 pulled likely before Oct 5. I normally use 200 for narrowband exposures, 0 for luminance and 335 for AF.

So the gain in the FITS is the actual gain used for the exposure? There goes 4 hours of data :(

Sven

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3 weeks 1 hour ago
hy
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Wrong gain in FITS header. #45243
I don't understand what you mean by AF after each change.
I think the most likely thing is that the header is correct.
You can repeat the start of your scheduler job and watch the indi control panel to see for sure.

I can't look at the old code right now, but the way it worked is that there was a start-sequence routine that changed gain.
If your auto-focus happened after that start-sequence ran, then, yes, very likely it was exposed with the AF gain.
Any code picked up after Oct 6 or so should have the fix.

How were you triggering the AF?

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3 weeks 1 hour ago
freiform
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Wrong gain in FITS header. #45244
I configured the sequence so that after each filter change an autofocus should be performed: I had Focus selected in the Scheduler tab and activated Auto Focus for each filter in the filter settings.

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3 weeks 8 minutes ago
hy
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Wrong gain in FITS header. #45245
Sven, Not sure when the gain change for that kind of focus would happen (pre-or-post start of sequence). I'll check tonight.

Anecdotally, one my list of things to look was this same "auto-focus on filter change" thing.
I once noticed that it auto-focused even if the Align module changed the filter, which I don't think makes sense.
Do you agree that it shouldn't auto-focus if the filter is changed by Align, but only by Capture?

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2 weeks 6 days ago
freiform
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Wrong gain in FITS header. #45246
As this is a new camera and it was the first image with on a new target (IC434) that is containing a bright star (Alnitak), I cannot judge the gain of image visually. Well, I suppose the background might give it away. I'll look into that.

To the question when to actually refocus, I think if you realign before each step of a sequence, either do the alignment at the end of the last step, i.e. the last filter is still in focus, or before aligning with the new filter, and you can then use this focus for capturing. Although this might cause problems if a sequence is aborted/stopped and resumed at a later point and woudl have to be caught programmatically, i.e. 'always focus on teh first step'.
If align is disabled, you can just focus after a filter is changed or a certain time has passed, or temperature changes (is this implemented?) or HFR runs away.
Theoretically, I do not think that refocus should be mandatory for every step just because it's selected globally in the sequence tab. Consider bright cores of galaxies or nabulae with high dynamic range where one wants different expsure lengths for the same filter. Why refocus? It certainly won't hurt, and the time lost really is of little to no consequence, but making this conditional probably adds unnecessary complexity in both programming and usage. Just considering whether or not to, you just might want skip between certain steps.

Another thing is that I do not think of EKOS' focus functions as especially robust, so I personally would not want to have unnecesarry focusing runs that might or might not cause problems, potentially ruining an unattended imaging run ;)

Sven

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