Hi Leo,
We have the same problem here, with LED they leave to light on all the night. I hope some regulation force them turn it off during night, for the birds and other animals out in the dark, and maybe some astronomers.
The dew is a problem, normally after 30 minutes I get dew on the front lens. I have installed dew heaters on the front lense, both main and guide telescope. Low power, about 1 Watt or lower.
Here are some:
http://www.astrofriend.eu/astronomy/...ting-band.html
Today most USB powered dew heaters in low power mode.
Lars