M31 The Andromeda Galaxy
It's now October, and it's cold enough to bring out the SLRs. This image acquired on a perfectly calm night with good seeing.
Rock Lake, Algonquin Provincial Park, Ontario; October 9 2010, 9:30 PM - 12:15 AM; T=-2 C, seeing very good. 200mm lens at f/3.5, ISO 800, on unmodified Canon XSi; autoguided; 10x500s.