It's been cloudy for a month now, so no observing or imaging.
I am continuing my long-term project of setting up the obervatory PC to work well in cold temperatures.
I had originally tried setting the PC up with a solid-state drive, thinking the lack of moving parts would make it an excellent cold-weather PC. The cold-weather part worked fine, but the PC was unreliable booting from the solid-state drive, and I eventually gave up on that and went back to the original hard drive.
The problem with the hard drive is that when the observatory is cold (below about 0 Celius), the hard drive has trouble getting spinning. Sometimes it fails completely, giving a BIOS error. Even when it boots, I have to believe it's not good for it to be spinning up when things are tighter than usual because of the cold.
I've experimented with keeping a small "no-freeze" electric heater inside the observatory, turned on all the time. This works, generally keeping the interior tempt at about 5 degrees C. However, it doesn't seem very efficient to be heating the entire dome interior just to keep the PC happy. Plus, the bay where the PC lives is offset from the main interior space, and tends to be colder than the rest of the interior, so I've had boot problems on very cold days even when the temperature in the "main" space is 5 degrees C.
So, I've ordered a small, thermostat-controlled "enclosure heater" from Omega Industrial. This small device should fit inside the PC cabinet and provide a small amount of warmth. A built-in thermostat will keep the temperature inside the cabinet at about 10 degrees C. I plan to wire it off the PC power cable, with a manual "off" switch mounted on the cabinet.
Normally, of course, one worries about cooling the interior of a PC, not warming it. But PCs aren't generally permanently installed in unheated outdoor structures. My assumption is that the PC will warm up when in use and the thermostat will kill the heater as soon as the PC is generating enough heat of its own.
I ordered a couple of different sizes of units (this long narrow one, and this more rectangular, squatty one) to have some mounting options. Both are low-power (60 watts) with built-in thermostats to hold the temperature just above freezing.
Photos and a report to follow once I get something working.
It worked. Here is the installation journal.