I'm sure most you have a DSO that brings in the cloud everytime you try to image it!
NGC 55 has been one of those, the image is made up from data taken on three nights. But becuase the cloud keeps coming in there's only 50 minutes of data. needs heaps more!
This image is cropped, ISO 400 - 800 - 1600 used, all five minute subs.
Cheers,