Problem with sequence

Cameras, telescopes, focusers and other hardware
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brujo
Posts: 11
Joined: 24 Jan 2019, 20:41

Problem with sequence

Post by brujo » 03 Nov 2020, 17:43

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.

fabdev
Posts: 230
Joined: 03 Dec 2018, 21:43

Re: Problem with sequence

Post by fabdev » 03 Nov 2020, 20:53

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).

brujo
Posts: 11
Joined: 24 Jan 2019, 20:41

Re: Problem with sequence

Post by brujo » 04 Nov 2020, 10:46

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 ?

fabdev
Posts: 230
Joined: 03 Dec 2018, 21:43

Re: Problem with sequence

Post by fabdev » 04 Nov 2020, 13:54

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.

brujo
Posts: 11
Joined: 24 Jan 2019, 20:41

Re: Problem with sequence

Post by brujo » 04 Nov 2020, 15:04

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.

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