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> When I have the live camera feed there are lots of small
> circles with smaller rings inside.

We experienced apparently similar 'artefacts' in a Spot-camera about 
once every 2 years due to humidity accumulation in the camera.
After sending it back for maintenance and paying a considerable amount 
of money several times, I successfully did the following some months ago 
when the problem reoccurred: i) open the cover of the camera, ii) find 
the big screw(s) which close the container for the desiccating material 
and open them (see important hint below!), iii) put the sac with 
dessicating material in the oven for 5h at 100degC, iv) flush the camera 
with dried nitrogen for 1h via the opening, v) reassemble everything  
(using Teflon-tape for the screws).
Camera works nicely ever since. Maybe others have a similar problem with 
their cooled CCD's.

Important Hint: be extremely cautious when opening the camera and 
removing the desiccating-sac and the old sealing material from the 
threads (!). If some material or dust falls into the camera and gets 
onto the chip-surface you're in trouble!

Christian M. Müller
JWG University Frankfurt