If you're into deep space astrophotography, this is not really news. It's all about exposing for the stuff you care about. When imaging DSOs (deep space object

If you're into deep space astrophotography, this is not really news. It's all about exposing for the stuff you care about. When imaging DSOs (deep space objects), you often don't care about the relatively bright stars nearby. But you do care about that faint little object in between. So you adjust exposure so the stars are usually blown out (overexposed), but the DSO along with the light pollution background have peeled off the left hand edge of the histogram. So now your DSO is sitting comfortably in the middle of the histogram, where you can process and extract it easily. In practical terms, for DSOs you tweak exposure until the big light pollution hump on the histogram becomes disconnected from the left hand edge of the graph. Turn exposure up gradually until there's a gap at the left hand wall. That usually does it. Overexposure is bad, but underexposure is super-duper-evil, so you must avoid it. OTOH, don't push things too far to the right - you still want some chroma info in the star halos.