Really nice observatories posted here. Here's my humble rool off roof observatory. It's your garden variety garden shed 8'x10' converted. The observing room is 6'x8' and the soon to be completed warm room is 4'x8'. In the middle of Canada at almost 51 deg. North, we need it in the winter. Minus 40 is not uncommon. If your thinking of building one, go for it. The convience of it is really worth it in the long run.
-------------------- SN8, LXD75, ETX 80, 4 1/2 inch Newtonian, DSI-C, Meade series 4000 eyepiece set, 10x50 binoculars. Various other goodies.