This is a simple system to cool a C11 SCT telescope. A ventilator is set in the secondary hole, and sucks the air out of the otherwise closed SCT tube. On the Celestron Edge C11, the cool air enters from the 2 vents at the back, after going through the micron sized dust filters.

If one does hyper star operations, the secondary is removed and use of this device does not complicate setup.

The fan is a 12v computer/electronic fan, easily repurposed from surplus electronic or bought online for a few dollars.