glend
30-06-2017, 10:02 AM
I was looking for a way to stop winter condensation buildup on my CGX mount, which is on a pier in my observatory, during periods when it is not being used (ie dormant due to weather, or mothballed for winter, etc). I had tried a couple of things, including insulation wrap, dehumidifier, but always found the mount wet again in the morning.
The solution here works, and is very cheap to make. It involved creating a heat reflective shroud to slip over the mount, and a small heat source (in my case a 25W decor type incandescent bulb - which produces minimal light but good heat output). Photos are attached.
The way it works: The reflective shroud (from Bunnings, aluminium folded batts, cheap: https://www.bunnings.com.au/ametalin-1200-x-450mm-pleated-silverbatts-insulation-16-pack_p0810225
) is ventilated at the top by a couple of small openings. The bulb generates heat which rises inside the shroud, warming the mount, and the heat plume exits out the top vent holes creating convection currents over the mount.
This should work for any EQ or Alt/Az type mount which is left setup in a cold location, say a shed, garage, observatory, etc. It will also work for mounts which have scopes on them but the shroud would need to be modified to cover the entire setup.
This idea is a new take on the old dob mirror heater (using a low watt bulb to prevent condensation on Dob mirrors when stored).
I have just finished testing this concept over two very humid (85% RH outside, 75% RH inside the Obs) cold (4C) nights, and the mount came through completely dry.
Modifications to the design could include being made to run off 12V if you wish using auto or boat 12V 10W bulbs in series. I have not bothered about timers at this point but a simple AC security light timer would work fine if needed.
The solution here works, and is very cheap to make. It involved creating a heat reflective shroud to slip over the mount, and a small heat source (in my case a 25W decor type incandescent bulb - which produces minimal light but good heat output). Photos are attached.
The way it works: The reflective shroud (from Bunnings, aluminium folded batts, cheap: https://www.bunnings.com.au/ametalin-1200-x-450mm-pleated-silverbatts-insulation-16-pack_p0810225
) is ventilated at the top by a couple of small openings. The bulb generates heat which rises inside the shroud, warming the mount, and the heat plume exits out the top vent holes creating convection currents over the mount.
This should work for any EQ or Alt/Az type mount which is left setup in a cold location, say a shed, garage, observatory, etc. It will also work for mounts which have scopes on them but the shroud would need to be modified to cover the entire setup.
This idea is a new take on the old dob mirror heater (using a low watt bulb to prevent condensation on Dob mirrors when stored).
I have just finished testing this concept over two very humid (85% RH outside, 75% RH inside the Obs) cold (4C) nights, and the mount came through completely dry.
Modifications to the design could include being made to run off 12V if you wish using auto or boat 12V 10W bulbs in series. I have not bothered about timers at this point but a simple AC security light timer would work fine if needed.