I have a Bower / Samyang / Walimex
500mm/6.3 mirror lens.
Walimex sells a 2x teleconverter as well.
Pretty sheep. Pretty short. Pretty light weight.
Goes with the advantages and disadvantages of a mirror telescope with obstruction in the middle.
Star colours are fabulously natural.
You'd just need a T2-Adapter. But most brands sell it equipped for specific camera mounts, anyway.
I use it on my Sony NEX e-mount.
Difficult to find stuff through the life viewer, though, without finder scope or goto.
So I got a 14cm mounting plate and a smartphone holder. Now the smartphone sits side by side to the lens and I can use the Skysafari app to locate things and direct the ballhead towards it.
Haven't had the chance to work with that smartphone thing yet. But it should simplify the process a bit - in theory.