Heh, I need to go back in there and check (It was good a couple of days ago though). I have the obvious entrance blocked with a piece of wood and some towels. Low tech, but functional. I'll get out there tomorrow and take a picture. I need to take a couple of quick measurements and order some strip brushes for a permanent solution. I've been stupidly busy with other, non-astronomy stuff this week though.

Anyway, back to your topic, I feel comfortable leaving all of my gear out in the observatory all of the time. I think you should be just fine. Just take what precautions you feel are prudent against the environmental hazards you face, and enjoy the freedom to observe at your leisure.

I really do mean you should do what makes you comfortable - the fact is that people who do remote imaging pretty much leave all of the gear uncovered all of the time (except for the observatory structure itself) so that the scope and camera are ready to go. So if you are comfortable closing your dome and walking away, that's perfectly fine - lots of people essentially do just that.

Now I think it's prudent to put away your eyepieces, and cover the scope with a tarp or something, but even that is not absolutely necessary.