I think a bigger concern might be to have it large enough so that you don't have to keep
moving the dome. I'd say roughly three times the size of the aperture. I did read some
estimate somewhere. It might have been in Patrick Moore's book on amateur observatories.
As for heat dissipation, cooling, and turbulence, you ought to consider forced air. Check
out such topics on Google. I think using something like "observatory laminar flow" might
do the trick. See my URL below, I may list several references on these topics. If not send
me an e-mail (see address below) or just re-post here.

Matt wrote:
Greetings,
For a 16" Meade Starfinder telescope, how big should the slit be in an
observatory dome to allow heat disapation, and light entering?
~ Matt


--
Wayne T. Watson (121.015 Deg. W, 39.262 Deg. N, 2,701 feet, Nevada City, CA)
-- GMT-8 hr std. time, RJ Rcvr 39° 8' 0" N, 121° 1' 0" W

"Why do you do it? ... You can't win. Why do you persist?", Mr. Smith (The virus)
"Because I choose to.", Neo (Mr. Anderson. The anomaly)
-- The Matrix (movie) Revolution

Web Page: home.earthlink.net/~mtnviews
sierra_mtnview -at- earthlink -dot- net
Imaginarium Museum: home.earthlink.net/~mtnviews/imaginarium.html