Trouble plate solving with bright moon

Discussion of using SharpCap for Deep Sky Imaging
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Moonstruck
Posts: 172
Joined: Tue Aug 17, 2021 4:34 pm

Trouble plate solving with bright moon

#1

Post by Moonstruck »

Hi Robin,
I routinely use Sharpcap's go to/plate solve function, which has been working really great for me until last night. Last night Sharpcap went through the go-to, then plate-solve routine, and indicated my image had successfully been plate solved, but the image (M101) wasn't on the screen. In a couple cases the image was there, but wasn't anywhere close to being centered- it was way off to the far right or far left corner of the screen. Any idea what is happening here? I got an "excellent" result doing a polar alignment beforehand so I don't think that was the issue.

This hasn't happened before - usually when it tells me the plate solve has been successful, the image is always there- and 99 percent of the time it is in the dead center of the screen. The moon glow was exceptionally bright last night. Could that have something to do with it? Anything else I should check? I was also using a 10' long USB3.0 cord, which has worked well in the past, but maybe the length of the cable combined with the moon glow caused the plate solve issue?

Any assistance will be appreciated. I am scheduled to give a livestacking demonstration to a local High School astronomy class tomorrow, and the moon will be bright again... should I postpone my session? Or is there something I can do?
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Menno555
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Re: Trouble plate solving with bright moon

#2

Post by Menno555 »

I don't know the answer, but adding the log file of the session where this happend, can probably tell Robin what happend.
Just in case on how to get the log file: you can find the SharpCap log files on C:\Users\YourUsername\AppData\Local\SharpCap\logs
Attach the log file of the session to your reply here.

Menno
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Moonstruck
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Joined: Tue Aug 17, 2021 4:34 pm

Re: Trouble plate solving with bright moon

#3

Post by Moonstruck »

Thanks Menno, but regarding the log file - I deleted all my images (and capture files) already, so am not able to provide anything. Sorry.

But maybe Robin has seen this problem before and can give me some general advice regarding the effects of plate solving with a bright moon? Or why Sharpcap said the plate solve was successful but the image wasn't there? Maybe he can just provide some possibilities on what he thinks it may be based on his experience? I am confident he has seen this sort of thing before and may be able to assist with some general guidance, if he is available.
Gfischer
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Re: Trouble plate solving with bright moon

#4

Post by Gfischer »

I found if you use mono8 for the camera color space it helps with bright skies.
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admin
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Re: Trouble plate solving with bright moon

#5

Post by admin »

Hi,

a bright background can cause issues with the star detection process that is part of plate solving, and less stars makes a false reading slightly more likely (still should be rare - SharpCap tries to calculate the chance of a 'random' match giving a particular plate solving result and ignores the answer if that chance is less than about 1 in 10 billion.

If you see this happen again, go to the 'Logging' settings, tick the box to log for plate solving problems (near the bottom) and try the procedure again - with that box ticked lots of info gets saved from the image used to plate solve to extra details about the results, etc. If you then send me all that info (it will be in a folder called 'PlateSolveImages' in the main SharpCap capture folder) then I have a good chance of being able to reproduce and understand the problem.

cheers,

Robin
Moonstruck
Posts: 172
Joined: Tue Aug 17, 2021 4:34 pm

Re: Trouble plate solving with bright moon

#6

Post by Moonstruck »

Ok, thanks. If I have this issue again I’ll send you the additional info.
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