I got this shot of the Moon over Cranston, Rhode Island using a 4" SCT and my Canon S95. Visible are Tycho Crater (bottom), Copernicus Crater (center) and Plato Crater (top).

Camera: Canon S95 (CHDK) with intervalometer attached a-focal to 4" SCT 1200mm, f/10
ISO: 80
Camera F-stop: f/2.8
Exposure: 0.13 second total exposure (64 shots at 1/500)

-Scott