Yellow, Ugly Images...
 
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Yellow, Ugly Images from APP


(@mountainair)
White Dwarf Customer
Joined: 2 years ago
Posts: 19
Topic starter  

Hello,

The last several months have been very discouraging, not only because of the clouds but also because it seemed like each set of data that I processed came out with this ugly yellow tinge that is problematic to remove.  They also always have vignetting.  Both these issues seem to be new, as I am using the same telescope, camera and image train I did for galaxy season last year and I didn't have these problems then.

Thinking I had bad (6-month-old) calibration data in my library for the ASI294MC-Pro, I reshot:

250 Bias @ gain 0 and 120, offset 8

50 Darks @ gain 0 and 120, offset 8 at all my typical exposure durations (300s in this case)

Today, I processed last night's M57 data with APP -- 30 lights, 50 flats, 50 dark flats and the 32-bit master calibration frames with the proper gain and offset and duration from the above library (which were processed in APP).  It again looked yellow on the screen, and when I opened it in PixInsight for the rest of my workflow it appeared stretched much worse, had bad vignetting and the amp glow wasn't totally subtracted.

Frustrated at seeing the same old thing, I spun up a Windows VM on my Mac and downloaded a copy of DeepSkyStacker.  20 minutes later, I was shocked to see a very nice looking image.  The screen shot attached is the APP and DSS versions opened in PI, with only SCNR and ABE applied.

I want to use APP for as much of my processing as possible, and want to avoid Windows and DSS, but the results I am getting are darn near un-workable.  I must be doing something wrong -- I see AMAZING results with APP from others.  Any ideas?  I use very much the defaults for almost everything.

SS

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(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 2035
 

@mountainair Hi! Sorry to see that you have troubles using APP. Which version of APP do you use? Did you do a “default” integration or did you change any of the settings? Does the same yellow image appear if you integrate without any calibration data at all? Are you using the internal HD of your computer or an external one?

There probably will follow more questions once you answer these. 

Thanks, Wouter


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(@mountainair)
White Dwarf Customer
Joined: 2 years ago
Posts: 19
Topic starter  

@wvreeven Hi Wouter, thanks for jumping in to help!  I'm using the latest stable release, 1.082, for MacOS.  The only change I made in this run was to step 3 Analyze Stars (changed to 2500).  In other attempts I did make changes to 2 Calibrate (to create 32-bit masters), 5 Normalize (to use Advanced mode).  Integration has always been default.

I am using a 2019 16" MacBook Pro with all files on the internal SSD drive.

I did also try various combinations of excluding the calibration frames.  The flats are definitely adding to the vignetting problem (I just read a followup to one of my earlier posts suggesting that we take much brighter flats at gain 0, which I will try tomorrow -- but DSS is using the same files and doesn't seem to cause this vignetting), but everything is still yellow (to a lesser degree, but still bad).

This post was modified 1 year ago 2 times by MountainAir

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(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 2035
 

@mountainair Would you mind uploading a sample of the lights and flats and the other masters to

https://upload.astropixelprocessor.com

using upload1 for both username and password? Please create a directory called mountainair_yellow and put the files in there. Let me know when they are uploaded and I’ll have a look. Thanks!


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(@mountainair)
White Dwarf Customer
Joined: 2 years ago
Posts: 19
Topic starter  

@wvreeven Done!  I've uploaded 10 from each.  Note I just realized the flat wizard gives the files the same name regardless of whether it's a flat or a dark flat.  The dark flats start with this filename: FlatWizard_2021-06-04_05-25-46__-14.10_4.82s_0000_120_8.fits and go to FlatWizard_2021-06-04_05-26-43__-14.80_4.82s_0009_120_8.fits.

Thanks!  I'm really curious what's wrong.


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(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 2035
 

@mountainair Thanks! I’ll have a look asap but probably tomorrow. 


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(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 2035
 

@mountainair OK I already had a look using 1.083-beta2 on my MacBook Pro. I did three integrations: without any calibration files, with the master dark, and with the master dark, flats and dark flats. All three integrations look OK to me.

Only the lights:

Screenshot 2021 06 05 at 16.37.46

With the master dark:

Screenshot 2021 06 05 at 16.38.11

With the master dark, flats and dark flats:

Screenshot 2021 06 05 at 16.37.57

Can you give 1.083-beta2 a try as well?


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(@mountainair)
White Dwarf Customer
Joined: 2 years ago
Posts: 19
Topic starter  

Those do look better than mine, though still yellow.  I tried playing with the color channel balance when importing and that does improve it, but it's time-consuming trial and error.  I am downloading the beta now and will give that a go -- wow, what a boatload of improvements in 1.083!

If you have a copy of PixInsight (sorry to even mention it here), could you open one of your stacked and processed files and do an STF?  That's where things really get crazy.

I wonder, could something about my flat panel be interfering with something in APP, but not DSS?  I have a 13-inch EL panel that appears somewhat blueish to the eye.  Come to think of it, though, I do see this problem with another EL panel that appears very white.

Thanks Wouter!


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(@vincent-mod)
Universe Admin
Joined: 5 years ago
Posts: 5130
 

It does look like the dark is causing an issue somehow. Just try it again without flats and see, if it produces this again there is likely something going on with the darks.


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