The history of Babylon is divided into two stages separated from each other by the period of Assyrian rule; the Pale Babylonian or Amorite Empire (1792 BC – 1595 BC) and the Neo-Babylonian or Chaldean Empire (626 BC – 539 to. C.). The Babylonian empire was succeeded by the Persian after the conquests of Cyrus II the Great. For the Babylonians, everything was handled by fixed rules: there was no logical method and the principle of causality. The beginnings of Babylonian astronomy date back to the third millennium BC. C. It reached its peak around 600-500 to. C. and declined in the last century before our era. To see the accuracy of much of your data We are going to give some examples: the average duration between two equal lunar phases (synodic month or lunation) is 29.530641 days; the modern value is 29.530589 days (see calendars). The value found in the second or first century BC. C. for the synodic revolution of the planets, that is, the time between two positions similar with respect to Earth, it did not differ by more than 1% of the day, from the current value: in the case of Venus, for Example is .583.91 days instead of 583.92 days. Only in the case of Mars with, 779,995 days instead of 779.94 days, a somewhat larger deviation appears, which, however, does not have to be entirely real either, because until recently it was not possible to observe the planets with modern measuring instruments (development of the Bessel systems in the 19th century), it is not possible to make a calculation with absolute certainty retrospective of the revolutions that, always subject to disturbances, were different 2 or 3 thousand ago years.
Unlike the Egyptian calendar which was solar based, the Babylonian one consisting of 12 months of 30 days, had lunar base: Created by the Sumerians, this calendar was later implemented in the empire Neo-Babylonian by the Chaldeans, whom the Romans will refer to as the astrologers and mathematicians. The Oldest Babylonian observation of a total solar eclipse (among those safely dated) is dates back to June 15, 763 BC. However, the periodicity of eclipses had been observed fairly before, surely in the third century BC. C., thereby obtaining the discovery of the Saros Cycle (223 months synodic or 18 years 11 1 /3 days; see Calendars), a period in which eclipses repeat, since the Moon and Earth return to relatively similar orbital positions; In this context, this was one of the most notable contributions of Babylonian astronomy. To this must be added the creation of the system sexagesimal: circumference in 360º and 1 ° = 60´, since the year is 360 days. The Babylonians originally used the lunar cycle to make a calendar. Every 12 months of 30 days made up a year. To absorb the lag with respect to the real duration of the solar year (365.25 days), occasionally added another month. Fixed rules to intercalate this month did not exist until the 6th century BC. C. From 383 a. 7 months were foreseen to intercalary every 19 years (lunisolar year). The division of the day began with the sunset. Around 1700 BC. C. approximately its division into equal 24 hours. The most important constellations already received their names in the third millennium BC Modern astronomy adopted most of the Babylonian names for the constellations of the zodiac.