Attached is a crop of my best (which prolly isn't saying a lot
) efforts at processing 2.5 hours of m83 on Sunday night.
I have not got guiding set up yet so I am still limited (by my patience) in drift aligning to a minute or two - this one is 120x75 sec shots with calibrated flats, no darks at ~2.7 arc sec/pixel (Tak FS60CB & Atik 314E).
I sort of walloped the credit card with my new EM11 and as I cannot yet afford Photoshop, will be making do with 8bit GIMP for the next few months. However I imagine many of the techniques are the same and would appreciate any suggestions on books or websites to improve processing - it appears there is a little more in the arms but I can't get it out without everything looking stark and over-processed.
This one is curves & levels and one pass of duplicating the pic to to another layer, dimming it & blurring it to 150 pixel radius and subtracting it from the original.
I apologise for lurking in the Deep Sky forum without contributing but I don't really feel I have anything to add just yet...