Originally I was going to have an axial fan in the back of the scope pushing air
through the telescope to vent holes just behind the corrector. I decided to try
something else first to see if it works. I'm going to have two of the blowers
seen in this photo recirculate the warmer air at the front of the scope to the
back in an effort to mix the air and keep it homogeneous. By doing this the
scope can stay cleaner by not introducing outside air. I'll have a power switch
so I can turn them off during observing if they introduce too much vibration.
These are the smallest blowers I was able to find (2" x 2" x 0.8") and they are
well out of the light path. Each blower moves 4 CFM of air and the interior
volume of the scope is about 4 cubic feet, so they should easily be able to
keep the air mixed.
This photo was taken 21 April 2000 with an Olympus D-600L digital camera.
Fan in Unpainted Tube
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Updated: 21 April 2000