[glend (Glen)]

The ASI1600 heater arrived today, very quick service. I have installed it, and used the opportunity to put in some new dessicant pills and replace the AR window (which i scratched when cleaning it with a sensor swab that was not clean, another story). I filled the sensor chamber with argon and taped up the seam with PVC tape. There is an internal O ring that the cap presses into, and the AR window has an O ring as well, so it seems pretty well sealed.
The heater is pretty easy to install, centering it is important of course, and there are two thin plastic stand off spacer rings supplied which go around the AR window, this is a good idea so that you can't screw the filter wheel on so far that it scrapes the membrane on the heater. The Y cable allow you to run the heater and TEC power off a single 12V plug, but of course the combination will draw a little more power, and it would be always on. I am thinking that I will separate these two power leads so that I can turn it on only when needed. I was not happy with the big stiff cable ties supplied so I will be using some from my supply. Photos attached.

Update: I just conducted a quick test using a battery and dedicated lead to the heater. Starting temp was 23C and after 20 minutes the cap edge was 30.6C, measured using an infrared temperture gun. ZWO claim an increase of 10, not sure if that was F or C. The issue i have is that it was heating the filter wheel as well as the camera cap, which maybe a good thing. So obviously the filter wheel is either touching the heater membrane or heating through the screw threads. A thin sheet of neoprene might insulate it better, or even some pvc duct tape over the back of the wheel housing, nothing too thick obviously. A cold night field test will be needed.