I've resigned myself to the understanding that the stability issues affecting the pi I'm using to capture sunset time-lapses are power issues. I'm using a nice usb power brick from adafruit that's specifically rated for this use, but... every apartment I've lived in over the last 10 years has had power fluctuations on the mains. Next idea: power it from a battery pack, hopefully one I can leave plugged in/charging while it powers the pi. That's kind of progress.
Toots for friends