[Atmos (Colin)]

This is probably going to sound like a bit of a noob question but I was wondering how people typically go about processing data taken over multiple evenings?

The question mainly goes towards image stacking. Is it better to...
1) Stack each individual night and the combine those "masters" together.
2) Combine the entire set of nights at once.

I have in mind Rolf's 150 hour marathons! Whether it is practical combining 40 odd images (masters) or hundreds.