The roof on my observatory is a hexagonal pyramid riding on 6 ladder bearings in a "L" section ring. The roof overhangs and has a large..... Gap under it allowing lots of airflow. Scope is covered , surrounds sprayed with surface spray . No problems with creepy crawlies , when the roofs open they can get in anyway.i think too much effort is put into sealing observatories.
PS its been up for 13 yrs no issues.
Regards philip
