That is great advice (i.e., to split the capture into separate RGB channels) I do not get consistent results when I do it.

I posted on the PixInsight forums and asked what the "experts" thought - what I got back was a consistent respond to the effect that while a few years back that may have been the thing today - the newer gradient tools actually process the channels separately behind the scenes so there is little point doing it.

Yeah - there is now way whatsoever I can do broadband from my burbs - I travel about 2 hrs north were our astronomy club as a Bortle 3/4 (SQM 21 - SQM 21.3) to do galaxy work. I have been able to get some targets like M27 and M20 with an Optolong L-PRO filter during New Moon nights - the SQM barely tips 18 - so you know it's bad if that is what you get during New Moon.

I will look for the details and I think I did a screenshot of my settings in GradientCorrection.  But GC was not the only gradient tool I used, I combined it with DynamicBackgroundExtraction and AutomaticBackgroundExtraction. I tried GradXpert that but did not seem to help - at all :-(

I believe that they (PI) just released a new version of GC for 1.8-9 - but I am not in the mood to upgrade yet, because you have to download the full version from their website and you will lose all your third-party scripts and will have to reload them - don't want to do that now.

Cheers and clear skies, and thank you so much for chiming in, please stay in touch!