Hi.
found a problem in the calibration software I was using and have now started to reprocess past efforts to see what might have been hidden in the data. The linked NGC253 stood out as a significant improvement, so decided to post the repro - please forgive. This is from data taken with a now retired GSO 200f4 Newtonian, and the bright stars are a bit ropey - but otherwise it was probably worth the effort. Thanks for looking. Regards Ray
http://www.astrobin.com/full/95597/0/
or in full native scale and resolution
http://www.astrobin.com/full/95597/0/?real=&mod=
image is cropped a bit.