[Doomsayer]

After reading Mike Sidonio's recent thread about even his FLI Proline CCD in-camera cooling struggling a little in the heat of last Saturday night I thought I should post some info about my water cooling system as I was imaging on that hot night as well. We all know that the SBIG ST and STL TEC cooling is not up to the standard of the FLI triple TEC system (I can't afford a class 1 PL6303 to replace my STL at the moment).

I have found my SBIG STL6303 battles greatly on warm to hot nights with just the TEC cooling alone - no surprises there. I was aiming to standardise on minus 20. I added simple water cooling which worked intitially, but soon found that the heat transferred from the camera to the water soon increased the temperature of the water in the esky, and the TEC was unable to maintain temp.

So I elected to chill the water a little in a more controlled way than just adding ice. I added another pump to the esky which runs the water through a programmable aquarium chiller. I bought a chinese made high capacity aquarium chiller locally for about $350. I set the chiller to a few degrees below ambient (mostly to avoid issues with relative humidity and condensation). The chiller only kicks in occasionally to level the temperature. Last Saturday night I was able to hit minus 20 with the TEC running at aboout 70-75% and the chiller set at 23 degrees and an ambient temp of 28 -30 degrees.

Admittedly, such a setup requires 240v power, so it probably only works for an observatory set up. I guess the FLI would hit minus 70 on a warm night with chilled water circulation easily, but we won't go there.

For more humid nights, you have to be careful with relative humidity - having a heater strap around the camera can be effective to reduce the risk of condensation inside the camera - if I went with this I could probably chill the water much more and get to minus 30 on warm nights.

guy