It has been a hot summer, often not cooling down at night at all, for many weeks now (July, August 2012). We’ve noticed that the peltier cooled CCD camera inside Allsky1 has rarely been getting down below 0deg C and as a result, is showing a lot more noise and less contrast than normal in its 90second images at night.
The image on the left is the existing vent with mesh inside (to stop the &#^$ wasps). The image on the right is the new 4″ vent (also with mesh), in the hopes of getting better airflow through the system and getting rid of more heat.

Offhand it looks like it worked. The last image of the nights run shows -8degC. Then again it did dip down to 13 degC last night.
It also look like it could use another coat of white paint on the wood housing. It helps keep the daytime heating down a bit.
The internal mask slipped a bit and the noise has returned.
This is the midnight image: