PixInsight used for all calibration, alignment and integration. Even with 3nm Narrow band filters I still get gradients due to light pollution. I used Dynamic Background Extraction to get rid of it.
I used drizzle integration to get full resolution back. Note that a binnedX2 image exposure for 32 min is equivalent to a full resolution image exposure of 128 min with a quarter of the read noise.
Data : SII 20f, NII 15f, OIII 18f. 32 min binned X2.
SII to red, NII to green, OIII to blue.
Used PS to tweak to the Hubble Palette using this recipe.
http://bf-astro.com/hubblep.htm
Full size image here 10MB
https://www.flickr.com/photos/343863...in/dateposted/
Bert