Yep, dome is no protection against dew. I leave my dew heater on after a session and put the scope "to bed" the next day (turn off the dew heater and cover up). I also turn on a small de-humidifier after a session to dry things off. This can take a while if the inside of the dome is dripping wet. In fact I run the de-humidifier all the time (except when I'm observing
) to keep humidity at 50%. In dry weather this is not expensive. I never want to have a mould problem.
Cheers, Marcus