Martin: Damn, had assumed the corrector lens in the Edge was up at the secondary. Sorry, bad advice on my part!
Martina: Have emailed friend. Will post here when he responds. The “forced ventilation” referred to keeping the small fan in my 300mm f/4 Newt going 24/7 – I am tempted to run it at 9V rather than 12 to spare the bearing a bit. Closing the tube or leaving open seemed to make little difference.
I did that in response to repeatedly finding condensation (water droplets and a fine dew plus a sheet of ice one night) on the mirror. Does the Edge have fans like the RASAs do?
Full dew conversation here….
https://britastro.org/forums/topic/suck-or-blow#post-615389