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HELP: Having a problem with Flats
in PixInsight
Hi Adam,
I was hoping you could help diagnosis a problem with me. I recently purchased a new scope, ES ED102 and put a .8 TS-Optics reducer on it. But I am having challenges with WBPP and calibrating my image. I have two other scopes (Redcat, Esprit) and have not experienced this issue before. Granted with the Esprit I have a mono setup.
My imaging night involves a full setup, and breakdown so I take DarkFlats and Flats at the end of my night (everytime). The camera I am using is the ASI183 MC pro and Antlia ALP-T dualband filter. I have used this camera and filter for over a year (on my redcat) and never experienced calibration issues before.
The flats always show a red ovel ring around the image (when using my redcat, ASI183 and Antlia ALP-T filter) but it always calibrated out so I was expecting similar in Flats taken by NINA. So I was not concerned when I saw the red oval in my NINA flats. I used the Flatwizard in NINA to capture my flats, my camera settings are -10deg, gain 111, offset 21 which was the settings when I captured light frames. I target a mean value of 32,000ADU and exposure length of between 2-5 seconds. I use a DIY flat panel, essentially a drawing light panel with several T-Shirts.
With WBPP I run at full quality, Cosmetic Calibration, keep all settings at automatic. I have tried adding a pedestial and ran it without one. The integrated image seems to have the red oval enhanced by the flats instead of being removed. It would be great if you had any suggestions on what I am doing wrong or how I should adjust my process.
Thank you
Adrian
Comments
Will try capturing flats without the reducer right now.
Appreciate the quick response.
Adrian
I believe, Adam, I have watched all your fundamentals videos and enough of your issue resolution videos so no need to hide a suspected cause. I trust your expertise, implicitly! Hence why I didn’t question changing the image train and retaking flats even though my gut was saying it did not make sense. Focus was going to be off and image rotation too.
I did not think to mention that I had run the scope the night before without a reducer but using a field flattener. It had the same issue flat field issue. I ran the experiment in reverse, replacing the flattener with reducer before reaching out. Haha
That said, I tried a few experiments today
1) redid the flats/dark flats - targeted 23000 ADU - same problem
2) re-did the flats - without reducer (misunderstood the instructions)
3) re-did the flats/dark flats -without reducer (further test based on the misunderstood instructions)
4) re-did the darks - used all three sets of flats/dark flats:original flats/dark flats, flats/dark flats based on 23000 ADU and finally flats/dark flats without reducer. Interesting enough they produced a flat image in all cases. Except it now seems to overcorrect the amp glow. When I was running all these experiments on flats/dark flats that maybe I should re-run the darks too. the darks I was using originally were from the redcat (using an Asiair). And I am not entirely sure, if the Asiair has offset control nor was I certain even if it did that it had the same offset, so figured maybe the offsets were different and I better eliminate a dark calibration issue.
I think I am on track to resolving as it appears to be bad dark frames. When I redid the darks and ensuring same offset, the calibration works way better. But I am not 100 there yet, just need to sort out the overcorrection of amp flow now…thinking the new darks may not have exactly matched the -10deg sensor temp from last night’s lights . the camera was in a closest, under a towel and my mini computer was throwing a lot of heat and is near the image train.
Tried running a a couple additional integrations adding auto pedestal and literal value pedestal to see if it improved the overcorrection. But it seemed to have made the overcorrection worse.
Probably going to re-run darks and get a stable sensor temp of -10degs. Looking at some of the fits header data, my sensor temp was definitely changing as the closet became warmer this afternoon.
Attached a picture of what I suspect is an overcorrection of the amp glow. Let me know if you think it is something else. Still working the issue but way happier with the calibration versus this morning!
Learned a lot today, so I call it a win…Appreciate your time on this!
Adrian