Text
The part of astronomy in which Babylonians pushed their investigation farthest was probably the determination of the course of the moon, which enabled them to predict the periodic return of eclipses. Undoubtedly this was one of the most ancient studies to which the people of that country directed their energies. The moon-god Sin was in their eyes a more considerable divinity than the sun-god Šamaš. Before the duration of the year was known, the phases of the moon served to measure time, and to fix the dates of sacred calendars. The star of night allowed herself to be observed by the naked eye better than any other, and it was possible to follow almost continuously her winding course in the heaven. The experience, extending over thousands of years had led the astrologers to construct tables, which had attained a high degree of precision at the moment when the Greeks under Alexander entered into direct relations with them. About the year 200 BCE these learned priests had succeeded in determining in advance not only the dates of the phases and eclipses of the moon, but also the principal phenomena of the five planets. The Chaldean theory of the motions of the moon influenced the development of Greek doctrines. An evident proof of this is supplied by the fact in the Almagest Ptolemy quotes, after Hipparchus of Nicaea (ca. 161-126 BCE), the eclipses of the years 621, 523, 502, 491, 383 BCE, observed at Babylon, and the first of these has been found noted in an Assyrian text. How absolutely the astronomer of Nicaea relied on his oriental predecessors can be ascertained from some figures. Ptolemy attributed to Hipparchus an extremely exact calculation of the lunar periods; but it is possible to demonstrate that the duration which he assigns to the various months is precisely that which is laid down in the cuneiform tablets, namely:
Mean synodic month 29 days 12 hours 44’ 31.3’’
Mean sidereal month 27 days 7 hours 43’ 14’’
Mean anomalistic month 27 days 13 hours 18’ 34.9’’
Mean dracontic month 27 days 5 hours 5’ 35.8’’
Clearly the priority of discovery belongs to the Babylonians, as well as that of the inequality of the length of the seasons, of which they were perfectly aware.
Sources (list of abbreviations)
Ptolemy, The Great Treatise 4.8.11
Ptolemy, The Great Treatise 5.14
Bibliography
| Cumont 1912, 59-62 | Cumont, Franz. Astrology and Religion among the Greeks and Romans. American Lectures on the History of Religions 8. New York, London: G. P. Putnam's Sons 1912. |
Amar Annus
URL for this entry: http://www.aakkl.helsinki.fi/melammu/database/gen_html/a0000786.php
|
