Cold finger design based off of one done by Anat here:
-Link to Anats Hyper Mod Much more detailed instructions on how to disassemble the Rebel XSi/450D are here:
-Gary Honis's instructions
Goal:
To cool the imaging sensor of the camera as much as possible to reduce noise signal of the camera at high ISO (sensitivity) over long exposures.
The aluminum "Cold Finger" sits under the imaging chip circuit board, and above the sensor itself. There is a very small gap here where the finger was inserted. It is then sealed up with hot glue all around to prevent moisture buildup. The top of the exposed circuit board is also sealed up with hot glue to prevent moisture.

This image shows the ground plate attached to the circuit board of the sensor, underneath the circuitry is all sealed with hot glue. The two bolts supporting the cold finger were inserted into the support frame for the sensor, which then screws to the camera body. Its is pretty solid.

Far view of all the plugs reinserted.

Camera reassembled.

Shot of the finished setup with the Baader MPCC attached.

The cold finger has been sealed up where it enters the camera body with silicone, then wrapped with insulation strips and electrical tape. This is to help prevent condensation from forming. You can see the temperature gauge reading from where the cold finger enters the camera.

After 10 minutes of cooling, it has dropped 49 deg F!

These next two images show the dark frames of the sensor cooled, and not cooled. You can really see the difference in the noise levels.
Not cooled, 4 minute exposure ISO 1600

Cooled to around 35 deg F, 4 minute exposure ISO 1600

Finished and mounted on the focuser.

I will post the first images shot with the peltier soon!