After seeing Greg and Andy’s amazing images I think I ended up reducing the background too much but I wanted to explain my processing of SH2-308 to see if I’ve done some kind of aberrant processing thing. I had around 6 hours of data at f4 from Bortle 6/7 skies. Aside from the usual calibration, background extraction, HOO combination etc. I made starless noise reduced version of both the Ha and OIII (attached, the Ha being the weaker) and used these as masks to boost and sharpen detail. The stars didn’t suffer any distortion this way and I could boost the weaker Ha. I’m just really curious as to how to do this better and more faithfully to the object itself. RGB stars certainly would have helped (centrally Wolf-Rayet should be blue I think?). Astrobin:
https://www.astrobin.com/full/o5302g/K/