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Problem with sequence

Posted: 03 Nov 2020, 17:43
by brujo
I am using Zwo mini filter wheel and QHY174MM cooled camera on AstroArt 7 SP4.
When running sequence, there is a problem with the first image of the next sequence.
As you can see in the image, the first dark image was taken while the filter wheel was still turning.

Re: Problem with sequence

Posted: 03 Nov 2020, 20:53
by fabdev
some questions:

1) Is the filter wheel an ASCOM device ?
2) Can you hear the motor still moving when the next exposure is taken ?
3) Can you exclude a problem caused by residual charge? The light image seems extremely saturated (65000-65000).

Re: Problem with sequence

Posted: 04 Nov 2020, 10:46
by brujo
It is all ASCOM.
It has to be a residual charge, because the filter wheel is fast enough.
Have inserted a dummy image of 1 second between LIGHT and DARK and everything is OK.
Is there some other way to "discharge" the sensor ?

Re: Problem with sequence

Posted: 04 Nov 2020, 13:54
by fabdev
The residual charge can be a problem only for extremely saturated images, maybe that was an indoor test. For astronomical uses it will not happen. Just make a test on the sky when possible. In the worst case it's simpler to just skip the first dark frame from the stacking.

Re: Problem with sequence

Posted: 04 Nov 2020, 15:04
by brujo
Yes, this was just an indoor test for demonstration.
But I have noticed this while capturing at night on a real target.
While taking L,R,G,B frames I noticed that the first image of every color was more like the last of the previous color.
Anyway, no problem, will use a dummy image.
It is probably an ASCOM issue for my QHY camera.