I have a Maksutoc Cassegrain telescope that I can mount to my eos bodies with a T-mount adaptor. 1800mm f12 and the moon close to fills the frame. I shot some nice moon images during the full lunar eclipse a couple of years ago - search through my flickr stuff (can't access through the work firewall). I keep meaning to lug it and the tripod out to shoot the local deer, but haven't found the combination of time and motivation yet
In reality, I don't shoot much long stuff at the moment. My longest everyday lens is the 100 macro or 24-105. But I occasionally use the 70-200 f4 or 70-300 DO (which I remain in confusion about really - the main advantage being portability for such a long lens.)
Jim, what do you do that uses a long mirror lens to shoot 360fps on film?
Mike
PS - to keep Rachel happy the biggest prblem is that it's folded up...