I have a rather silly beginners question, but does a dob cool down faster with it's dust cover off? I'm guessing it does, as it would open up the tube to the air that it is trying to reach equillibrium with.
The reason i'm asking is that the last few sessions I've had a fair bit of dew. My routine for setting up is to take all the covers off, carry the scope outside and then turn the fan on. I leave it cooling for about half an hour while I read the kids a story and put them into bed, and then head out.
My last session the finder scope and the telrad were dewed over before I even got out there, and the secondary mirror only lasted for an hour before that succumbed as well. I've made a foam cover as a dew protector for the telrad, and one out of a plastic pot plant pot for the finder scope (I'm also not taking the cover off those before I'm ready to observe, that was a real no brainer on my behalf
) but I'm wondering if I could forestall the dew by leaving the cover on the dob too without affecting cooling too much. Do I need to let my eyepieces cool down as well?
Thanks all
Ant