Green channel was very noisy with horrible LP gradients in it so synthesised G from R + B. Still noisy though.

Object ID M51 Whirlpool Galaxy
Details Red channel 2020-02-15
Blue channel 2020-02-18
Telescope 250mm f4.8 OO Newtonian
Camera Atik 460EX@15C
Baader RGB
Exposure(s) 15x180s ea RB
darks, flats, bias
Capture APT
Processing SIRIL (first time)
Photoshop