For anyone reading this later (too late for OP), a few hints regarding noise:
What those of us who do astrophotography do is to take dark frames, the trick is to take them using same settings that you used to take the 'light' frame, for equal amount of time.
That's bad news if you are taking a 3-hour shot. So, the work-a-round is to make a Master frame collection, start building up dark frames, then averaging equal settings with equal settings, then make Master frames, keeping track of settings for later use. Just make sure that all things are the same, like temps, darkness, etc.
What I have found to be fairly good is to take anywhere from 9 to 15 dark frames, average them out and make Master frame.
To take the dark frames, just put the cover over your lens and go for it.
And yes, stacking the light frames does help...