Here is M45 taken with Canon 20D Canon 300mm F2.8L.Five exposures stacked with Registar each 190sec at an ISO of 1600 at F2.8,in camera noise reduction on.Hutech LPR filter.Quick tweak in Photoshop.Moon still up,but its better than a picture of a cloud.
http://users.bigpond.net.au/avandonk/M45.jpg
Bert