NGC 891 (Silver Sliver Galaxy, or Outer Limits Galaxy)

Acquisition:

Bortle 7 skies
Nikon D5600 camera (unmodified)
ISO 200
Astro-Tech AT102ED refractor, 714mm focal length, f/7
HoTech 2" SCA field flattener (1X)
iOptron CEM26 mount
30s x 397 frames (3h 18m)

Processing:

Siril 1.2.1:

Crop to 4000 x 3000px
BQ Octantis' color processing steps (white balance, background subtraction, histogram conditioning)
StarNet++:
Background: modified asinh stretch, background extraction, saturation
Stars: modified asinh stretch, synthetic blue, saturation

RawTherapee 5.9:

L*a*b* CL curve (to reduce background chroma noise)
Luminance noise reduction

GIMP 2.10:

Luminance curve
Saturation
Slight temperature reduction