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Time to fire up the mount heater shroud again.
The start of May is when I usually re-install my mount heater shroud in the observatory. It has proved a very useful device for preventing mount condensation, both internal and external. I did a thread on it years ago, which might still be here somewhere if you search for if.
I should point out that this is a mount only heater, my scopes (refractors only these days) live inside the house. See my comments below about Dob heating. Also my CGX mount is pier mounted, so no tripod in this concept.
Basically it is an aluminium foil insulation shroud, with a low WATT incandescent bulb inside which creates a warm chimney effect, which keeps the mount above dew point. There is a small opening at the top to allow the rising air to escape, thus providing convection circulation.
Don't jump to conclusion about what i describe as aluminium foil, it's not what you use in the kitchen, rather foil batts that are used in roof or wall insulation. It does not have great R value, but being reflective it bounces the heat from the bulb very well. The bulb is a 30w decor type incandescent, with the orange glow filament, chosen for its heat output not light.
Power is provided by observatory AC through a 24hr timer. Normally it cycles on and off during the night, it only has to maintain the convection chimney effect with a bit heat.
During the day it is normally off, as the observatory heats up anyway. Last year, my son gave me a wifi power switch which i can use to program the on off cycle, which is controlled via wifi from the house.
I used a very similiar setup on my 12" and 16" Dobs of years gone by, but they used Telegizmo shrouds. In my experience Heated Dob shrouds do tend to require more heat, given the significant mass of the primary mirror.
So a heated shroud, in my experience, is a good way to look after your observatory mount and prevent possible corrosion due to condensation inside and out. And for prolonged storage it allows the mount to be left in situ.
Last edited by glend; 01-05-2022 at 04:18 AM.
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