slits in observatories? which way is best?

Gang: looking for input into pros/cons into which way of opening is best on a dome--slit moving horizontally or moving vertically. I'm interested in both the theoretical as well as the practical responses. Thanks in advance! Rich

Hi Rich,

I've desided on the rollover. I think it is easier to build, and less prone to problems from wind. Opening to the sides act as wings. I've been told by people who have had them for 20 years that there is no problem with them. I was concerned with snow and ice build up but they say no problem.

Dan