出典:Wikipedia
出典:『Wikipedia』 (2011/03/28 15:25 UTC 版)
The Decans (Egyptian bakiu) are 36 groups of stars (small constellations) which rise consecutively on the horizon throughout each earth rotation. The rising of each decan marked the beginning of a new decanal "hour" (Greek hōra) of the night for the ancient Egyptians, and they were used as a sidereal star clock beginning by at least the 9th or 10th Dynasty (ca 2100 BCE.)