Day and night
Day and night indicator is not a very precise instructions, because it can not function takes different latitudes and seasons, the changes in the length of day and night, alternating black and white days. Like in the picture only Panerai watches, day and night to open a small display window, below a black and white half of the dial on to the following luxusuhren in a small second hand, do not you see, is not often seen. About 5.30 pm in the afternoon, some began to reveal a black, completely black until the time-8.30pm.
This fixed pattern can not take care of all the latitudes, of course, including the season; in high-latitude regions, the dawn and evening are long, or that in Russia there are the quiet dawn of it? Beijing 39 herrenarmbanduhr degrees north latitude and more, during the annual winter solstice hours, days off work at 5 o'clock it was dark; and when the summer solstice, at 8 pm, it was still light and spacious.