Cooling seems not as strong as I am used from ccd cameras. The vent blows a steady stream of air out of the case, and I was able to get to about - 33°C below ambient.
Download speed in bin 1x1 over USB2 was around 2 seconds. Seems that the sheer size of the frames needs some upgraded hardware on my side though
It may be that ~35C below ambient might be all you need. Most of these modern Sony CMOS cameras have very low dark current, and the higher grade sensors like this one also have pretty low DSNU as well. I wouldn't expect to see -60C cooling with a CMOS sensor (and in fact there sometimes seems to be concerns about cooling them too deeply due to the fragility of the sensor structure, since they now etch both side of the sensor with BSI designs and the overall structures are quite complex these days).
That said, the venting does not really seem sufficient... One of the things I like about the CMOS cameras I currently use is they are very WELL vented, so even the slightest breeze at night helps move all that heat away from the camera and keep the heatsink cool. Might be some worth-while feedback for QHY if you find you cannot get the camera as cool as you would expect when actually using it on a scope at night.