Good starting point for astro on a normal SLR or what not...
F as fast as possible - i.e. apature F2 / 2.8 / 4 depending on ya lens - adjust ISO acordingly.
Shutter speed try and keep to under 10sec on a 50mm equiv... 4 sec gives nice sharp results @50mm.
If you zoom more you need a faster shutter to freez the pannig of stars and details.
At 1200mm zoom the moon will move compleatly accross your screen in about 2min!
Moon shots use a similar exposure to earth daytime!
e.g. 100iso, 1/400th sec F5.6/whatever your lens sharpest apature is.
Do your dark frame with same settings and lens cap on... that way your subtracting the same amount of sensor heat build up noise and electronic amplifacation noise. (i.e. dont use an ISO 100 with 1/250th sec shutter speed for the dark frame to use on long exposure shots, as this will result in very diffrent noise structure in the dark frame.)
Not my pic related - i wish