So I've made an insulator + dew/light shield for my 6" SCT, using a thermal material that is meant for campers, consisting of some ~5mm black matte foam, with mylar on one side:It's a little long, but I understand that will help delay the appearance of condensation. I'm not sure about the effect of it also being a full body cover (the "insulator" part) but I'm hoping that will help the tube retain heat longer and afford me more observing time before dew shows up. The place I'm going to has 85% humidity, and dew point at 18°C, which is reached at just 8pm, with temperatures dropping further to 14°C at 1am. I only intend to observe for a couple hours (from 7:30 to 9:30pm maybe) so there's hope this might be enough despite the lack of a heater.If I find something interesting I'll post it here.
I'm at the final location of my trip, where it's cold and humid at night. Last night I was able to observe without dew problems.
The 6" SCT had been stored in the cabin through the day. Around 8pm when I went to take my tripod out of the car, the car was already covered in dew.
I set up the tripod/mount, went inside, installed the DIY dew/light shield/insulator, finder, eyepiece, and then went out.
I had no problems observing, although when I tried to use my hoodie to block some stray light, I ended up fogging my Baader zoom, so I had to switch to my 82° eyepieces and not use the hoodie.
By 10:30pm dew still had not formed on the SCT, but I was done and tired, so I picked everything up and went inside to sleep.
So the insulator was a success, and gave me what I needed: ability to observe for a couple hours without dew.
Edited by Adun, 20 January 2019 - 07:31 AM.