PixInsight, Photoshop CS3, Noel Carboni's actions.
Color Balance: The integrated light of the galaxy was used for the
PixFix32 (pre-beta) to
repair column defects.
CCDStack to calibrate,
register, normalize, data reject, combine the sub exposures, RGB
combine & selective deconvolution.
PixInsight for gradient removal.
for non-linear stretching, LRGB
combine and noise reduction with the
Noiseware Pro plug-in.