[Zander]

hey guys. i was out last night with my telescope doin some viewing and imaging and it was all fine. it was a very cold night though and sum condensation was forming on the outside of the OTA. this mornin, however when i take a look at the primary mirror, it is all dirty from the dew that formed on it.
how can i prevent this happening? this is the second time it's happened, and i don't want to keep having to clean my primary mirror, thereby speeding up the optics decay.

here's some pics of the mirror.
any help would be much appreciated.