My earliest shots of the moon were taken with the 350D / Rebel XT and the 70-200mm f/2.8L IS, and I was happy with them at the time, so you will get something with that combination.


The extra crop factor and higher pixel density of the XT will give you more resolution for the same image. I haven't studied the difference in noise, but you still have time to check Bryan's reviews. On the other hand, you might feel more comfortable nailing focus with the 1D's micro-adjustment or Live View, which your older body lacks.


It's bedtime here, so I'll sign off for tonight and check back tomorrow. Good luck.