Here is a closeup of some of the HII regions in M31, the Andromeda galaxy. M31 is bursting with HII regions, but the extra-galactic nebula hunter is more usually drawn to the exciting regions in M33 and not the more subtle stuff in M31. Just imagine how some of those must look from nearby star systems? I've taken 12x1200s of data, so 4 hours, with the Skywatcher 200 Newtonian on the homemade mount using the 6nm Ha filter. The moon was rising towards the end of the exposure run. I have seen some extremely comprehensive catalogues of the HII regions such as this paper however I've not tried to label all the regions. Hopefully this diagram of M31 gives a fair indication of the field represented by the image.
Captured in Maxim and processed in Photoshop
Exposure Details :
Astrodon 6nm Ha 12x1200s on 200mm @ F5 with ART285
Curdridge Observatory, Southampton,UK