Overexposed MOV files with T1i

I have been trying to shoot MOV files of Jupiter and they come out overexposed. Has anyone else had this problem? In the past they came out fine, but now Jupiter is too bright to work with. Using a Canon T1i on the back of my C11 with eyepiece projection and a 15mm eyepiece, In the movie mode, how do you change the exposure and ISO? I thought this was automatic. What about automatic exposure lock and am I changing the exposure when I focus? Any help would be appreciated, even knowledge of a Canon user group forum.
robin

Robin: Give EOS Movie Record a try. It's free and gives you more control over video mode in a T1i than the base Canon software.

http://sweiller.free.fr/Canon40D/Canon40D-webcam.htm

Bryan