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Re: Schmidt-Newt and Exposure to the Elements

Started by Preston E, 01/23/2006 08:17AM
Posted 01/23/2006 08:17AM Opening Post
Hi Jeff, I live in Houston and am also building an observatory.

I'm on the Observatory Committee of the Houston Astronomiocal Society with our observatory in Columbus and am affiliated with the George Observatory with the 36 inch RC and 11 inch refractor.

The key to keeping optics in good condition is to us something that dehumidifies the air. In Columbus we have a C14 and two 12.5 inch refractors in a building that has a sliding roof. There we have a dehumidifier and airconditioner in the scope area. The airconditioner is set to 78 degrees and the DH to run if the Humidity rises above 50% RH.

At the George it is not effecient to run a true DH unit at the dome as it is 50+ feet in diameter. There they use a heating unit the measures the outside air temp and inside temp. The unit as I understand keeps the air inside 2 degrees+ above the outside temp...during the fall, winter and spring...not sure how they handle the summer.

My dome is 10 feet inside diameter and I plan to a small DH unit and a chiller from our ground water pump( temp of water 52 deg F) so that I can control the inside temp to the expected night temps for the early evening. The dome will house a 14 inch Lurie-Houghton and I would not want the corrector to dew up or mold...

One can also cover the optics, but in my case the entire dome and scope will be robotic and having to uncover the optic end would add even more complexity.

Another possibility for correctors is running a dew control system that sences the corrector temp versas air temp and keeps the corrector at a couple of degrees above air temp...

Hope that has helped,

Regards,

Preston