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Old 28-08-2020, 01:30 PM
FrancoRodriguez (Franco)
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FrancoRodriguez is offline
Join Date: Mar 2019
Location: Clifton
Posts: 65
Help needed with flats processing

Hi, I hope this is the right place to ask for advice regarding postprocessing. My master lights appear to be better when not using flats. This is very annoying, I use a 100mm frac, an ICX814 mono CCD, and flats with a flat panel and window tinting plastic to reduce the brightness. Some specs:
1200s Ha frames of Helix nebula
Weighted Batch Preprocessing script in pixinsight.
Calibrate flats with flat darks box UNCHECKED because I don't have 27 second dark frames (when unchecked it uses the closest dark exposure, IE bias frames for subtraction)
See the following 4 images: master lights without flats used (screen transfer function applied), master lights with flats used, also with STF (this is the worse of the two images, hence this thread), master flats with STF, and master flats stretched unstretched.
I haven't done any processing other than STF to anything.
Could someone help me with what's going on?
The darks and bias appear to be very smooth and I'm using a CCD so there's no visible amp glow. I haven't added these
Also, I had to compress the hell out of the images. They don't look very good, but you can see what I'm getting at
Attached Thumbnails
Click for full-size image (masterflatsscreentransferred.jpg)
333.9 KB21 views
Click for full-size image (masterflatNOTstretched.jpg)
51.4 KB20 views
Click for full-size image (AmasterlightNOFLATS.jpg)
202.7 KB24 views
Click for full-size image (AmasterlightWITHFLATS.jpg)
204.5 KB25 views
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