Astrophotos from Punggai Trip 20th Feb 2009

[cataclysm]

1 stage cooling should be OK with a basic sealed chamber with dessicant. 2 stage (like remus's camera) will probably need a real tight sealed chamber with a few hours of fresh dessicant inside to prevent dewing. But i think on the worst nights, it will still dew up.

Thanks. Looks like I need more experimentation to make the camera work.

[rcj]

As far as i am currently aware, the SBIG ST series utilizes an improved single-stage cooler with a revamped heat exchanger that is able to go down to -35 degrees Celcius typically with just air cooling and -45 for water assisted cooling. But this will not apply for hot climates like the tropics as this will operate beyond the recommended rating suggested by SBIG. Those living in cold climates will be able to experience lower operating temperatures. The only time I last experienced frosting (not dewing) was in the Desaru Golden Beach resort because the camera was housed openly in the air con room (wet, high humidity) from due negligence. With the PWT dessicant option, it was never a problem anymore. We had cases of wet nights here before, but the camera was still working fine. The dew controller however, was not delivering enough and caused the front scope objective to dew up eventually. I think the issue here is to constantly ensure that the camera is sealed properly but also not let it into an environment beyond 85% humidity for an extended period of time. Even during transportation during MY trips, the camera is housed in a sealed camera plastic box with selica gel, and kept inside whenever not in use during the course of the trip. At home, it is always kept in the dehumidifer.

Hope this helps.

[amin7074]

...nice one Meng Lee.
M83 and your Comet Lulin especially.