NGC 2903

Acquisition:

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 480 frames (4h)

Processing:

Siril 1.2.1:

Crop to 5000x3500px
BQ Octantis' technique of white balance, background subtraction, and histogram conditioning
StarNet:
Star desaturation
Background: modified asinh stretch (8X), background extraction, saturation
Stars: synthetic blue (B=2G-R), modified asinh stretch (5X), saturation

RawTherapee 5.9:

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

GIMP 2.10:

Luminance curve