NGC 2420 (Twinkling Comet Cluster)

Acquisition:

Bortle 7 skies, with 79% Moon
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 121 frames (1h)

Processing:

Siril 1.2.1:

Crop to 4000x3000px
BQ Octantis' technique of white balance, background subtraction, and histogram conditioning
Modified asinh stretch (5X), generalized hyperbolic stretch
Background extraction
Histogram midpoint adjustment
Synthetic blue - Pixel Math to replace bloated blue channel: B=2*G-R
Saturation (2X)
RawTherapee 5.9:

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

GIMP 2.10:

Luminance curve
Saturation
Black point