I have the Panasonic DMC-FZ28, a great little camera with a wonderful zoom. There is a Starrysky program where you can do 15 30 or 60 sec exposures - not as good as a DSLR, but not too bad.
I took a pic of constellation of Orion from a rooftop in Barcelona last year, and turned out great.
Am sure the Canon has great features too, and either would be a good buy.
Bet that didnt help at all
