Hi Mark ...
yes it probably was Wayne's scope. I wasn't aware it was "only" f/11. Although I never got a look through it I'm not surprised re the thermal problems - my 12" started life with a closed box tube which was likewise dreadful, which lead to chopping it up to make an open truss using glass fibre composite construction to lighten it and let air flow freely.
It's the scope at far left
http://www.iceinspace.com.au/forum/a...se.php?a=51343