Dear Scott

You could try hanging compact discs around the outside of the observatory. You need to hang them from something like fishing line so they turn in the breeze, one every yard or so. Wasps and other insects cannot stand the sudden flashes of light as they revolve in the sun.

I apologise if this is a well known practice in the US and you have already discarded the idea. But in Greece many people use this technique when doors and balconies are open in the summer - and it seems to work. Of course the observatory might take on a different, more glitzy appearance - but it is only for their nesting season, they can come down in the fall/winter.

Just a thought

Richard