[sheeny (Al)]

Originally Posted by h0ughy

well its always cooling down - its in the observatory....... i opened up the observatory and put the fan on for 3 hours before imaging

Is the fan blowing across your OTA or just extracting air from the dome?

I use a 12" fan blowing across the OTA of the C11 because it takes forever to cool compaired to the C8. The fan needs a good 1 to 1.5 hrs to get rid of the tube currents in the airey disc (throw it out of focus and you'll see the tube currents as a vertical column or "trees" through the airey disc). Then you've just got normal cooling rates to worry about.

I can also get rid of half my dome to help it cool too... prolly not so easy in a full dome.

Al.