The Mauna Kea night shift was an 18-hour night in wintertime at the 13,796 feet summit (before sunset to after sunrise) with insufficient time for adequate sleep before the next night shift. Night shift was between 5 and 8 nights long, and we slept at 9,200 feet. We sat at a desk staring at four large computer monitors and a large cathode ray tube television. I would also use my Wi-Fi laptop computer. I would have extreme fatigue by the end of every night shift and have chapped lips which I now associate with exposure to the artificial light from the computer screens. A good day of sleep between shifts was rare and starting the next shift fatigued was normal.