This camera is fairly new
These were all taken with, I repeated the process precisely the same for all tests.
As you can see in the last two images the galaxy is in different position, but blotching is fixed to sensor.
The banding was reduced quite a bit by changing usb from 100% to 40% (sharpcap 2.10) but blotching remained the same.
I also did a test with same settings from firecapture too, with same result blotching.
These were all done with temp at -20
Interestingly though no cooling seemed to reduce the blotching, but a bit hard to tell because of the heavy noise pixels
asi1600mc, 42 x 15 second shots .
stacked with ccd stack
then used ABE in Pix which then reveals the blotching effect.
With the raw single frames of the 42 shot, doing an ABE in pix, you can just barely see a blotchy effect it is extremely faint tho.
The use of darks, bias made no difference at all either
I have spent quite a few hours looking into this, to be sure that it was not a faulty process on my part.
I hope someone can tell me what the issue is.
I am suspecting the camera is faulty
EDIT: I have added a stacked photo and one raw frame from the set
https://1drv.ms/f/s!AkHzMIraVPd9g98j1ENqi-N7JfBDYA
