Classic History (@ClassicHistory)

Greek astronomer Hipparchus of Nicaea was the first person to compare celestial observations recorded centuries apart. He noticed that the positions of stars appeared to gradually shift. Around the year 130 BC, Hipparchus used ancient observations from the Babylonians, Meton of Athens (fifth century BC), Eratosthenes, and others, and compared them to his own. He concluded that in the preceding 169 years those intersections had moved by 2 degrees. He was able to measure this change by comparing readings taken during one specific day of the year, the Spring Equinox. Twice per year, the durations of day and night are equal, and the Sun rises exactly in the east and sets exactly in the west. Hipparchus concluded that the intersection marking the equinox slowly crept forward along the ecliptic, and called that motion "the precession of the equinoxes. " The rate is about one full circle in 26,000 years. http://www.classichistory.net/archives/time #Precession #Zodiac #Astronomy #Equinox