Messier 15 (Pegasus Cluster)

Acquisition:

Bortle 7 skies
Nikon D5600 camera
ISO 200
Astro-Tech AT102ED refractor, 714mm focal length, f/7
HoTech 2" SCA field flattener (1X)
iOptron CEM26 mount
30s x 219 frames (1h 49m)

Processing:

Siril 1.2.0-beta2:

Crop to 4000 x 3000px
Photometric color calibration
Background extraction
Star desaturation
Generalized hyperbolic stretch (twice)
Manual histogram adjustment
Cyan/blue saturation reduction (to remedy blue chromatic aberration)
Global saturation increase

RawTherapee 5.8:

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

GIMP 2.10:

Levels