I have over the years had problems with dew forming on the inside of my observatory and with heat in the summer.
Painting the roof white got rid of the heat problem, now it sits very close to external ambient temperature.
Recent insulation and lining of the enclosed half will prevent dew forming in there, but the open half it will still form. In winter I sometimes keep a 60w light on to keep it that bit less dewey. But that isn't really enough to have a huge impact, just a little.
I usually figure that as long as it's no worse than the dew the equipment would get during a full night of operation then it's OK. Just have to watch the drips from beams on the roof.
I'm not sure what the best solution is for such things. I'm not going to line the open half of the obs.
Oh that's right, last year during winter I put a heater on thermostat so it'd turn on at about 5 or 10 degrees. That helped, but must be one of the more expensive options.