Regarding cooling the Peltier TEC hot side, I currently see three options.
Large aluminium cooler with forced airflow
Large aluminium cooler passive
Nofan
It would save work without forced airflow. Nofan seems best but costs money. Still considering but favouring 2. or 3.
Whichever cooler I use, I need to make space for dew heater resistors (unless I vent warm air from the cooler up to the dome, which I've pretty much rejected). It would also be nice if I could include remote focussing. Here is the current assembly without cooler.
I think dew heater can go around the bottom inside of the dome. That may still leave room for a focus lever. I'll add to the drawing...