Quote:
Originally Posted by glend
Steve, so obviously the tube is open at the bottom, in order to get convection flow through the tube when the sun heats it (which evaporates the dew). I have a similar larger foil insulation shroud for my CGX mount inside my observatory, which is boosted by a 25w incadescent light bulb to create a rising air column at night. I live next to the water as well and dew is a constant problem.
I would suggest you check your equipment at dawn before the sun hits the tube, i believe you will find it is still wet. The sun hitting the tube will eventually get rid of it, but that leaves alot of dark hours when it will be wet. I suggest you try a small bulb near the bottom of the tube to generate convection lift. This is an old trick that dob owners use to keep mirrors free of condensation when the scope is not in use.
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Yes, the bottom shelf has generous openings to encourage an upward convection current. Likewise the other shelves have plenty of air holes and gaps.
Despite being near the water, we seldom suffer significant dew. Maybe it is the 70 meter of elevation, being exposed right at the end of the Tinderbox Peninsular and the fact that the thin soils in the area are seldom very wet keeps the dew levels done. Who knows! On the nights where I have packed up and there is light dew on the mount I have found it gone in the morning, even before the Sun rises.
Your low wattage globe on a timer sounds like the solution. Even if only as a precaution down here. Best to be “safe than sorry”. Thanks for the heads up.