Ok, had the scope in the dome for only a few days now and already I have noticed the optics fogged up when I have a look down the tube the next day

the mount and camera were soaked too and this was 2pm. It is high humidity here in Canberra at the moment with fog until midday but I wasn't expecting this.
My dew abatement works fine during the imaging session but what do others do for keeping moisture at bay during the day inside a closed unattended observatory?
Mike