That's why most actual astrophotography is done with peltier cooled CCDs - firstly a lower temperature means less noise, but more importantly more consistent noise. You can then shoot dark, bias and flat frames, respectively average those, then subtract them from your stacked (averaged using any number of algorithms) light frames.
No reason it couldn't be applied to regular long exposure photography using a DSLR, either.
No reason it couldn't be applied to regular long exposure photography using a DSLR, either.