Camera saturation - image compression level

[Bastien]

Hi,

some people in France (from La main à la pâte) designed a telescope for
the XO.  It's a cheap ad hoc device they stick close to the camera, and
it can zoom by 10x -- useful for observing, say, the moon.

At this stage of the project, they have two problems:

- shots of the moon are often saturated: how to reduce the gain
  of the camera?  Ideally one would like to do this manually...

- is there a way to take pictures with a higher resolution?  the 
  default compression level doesn't produce great pictures.

Thanks for any feedback!

-- 
 Bastien