But how did one day differ from the other? That was the question for the priests to determine. During the hours that the sun was in control, the clouds produced constant changes in the appearance of the heavens, but because of their irregular character, these changes impressed the Babylonians less forcibly than the striking changes that the nights showed. The planets and stars never appeared alike on two successive nights. There was always some change in the position of some of the heavenly bodies. To these changes, then, the priests directed their attention. In the variations presented by the heavens at night they saw a potent reason for the varying results produced by the same act undertaken at different times.
If it made a difference at what moment something was done, that difference could only be determined by observing the variations that one night presented from the other. The astrologers observed that many of the stars were, or seemed to be, fixed in their orbits; others rose and set like the sun and moon, and appeared in different parts of the heavens at different seasons of the year. The regularity of these changes made it possible to study the course of these stars, and as knowledge progressed, to determine also in advance where a particular body would be seen at a certain time.
The planets accordingly were the bodies to which the astrologers especially directed their attention. It has been conjectured with some show of probability that one of the purposes served by the lofty seven staged towers,[595] which were attached to many of the great temples, was for the better observation of the movements of the planets. The official standing of the astrologers is indicated by the references in texts to the 'court astrologer.'
However this may be, there is no doubt that at all the large temples and at many of the smaller ones, observations of the planets were recorded.
The collection of these observations formed the manuals for the priests in answering many of the questions put to them. Each of the great planets was identified (by a process of thought that we will have occasion to describe) with some deity, though this was not done until the attempt was also made to gather the astrological knowledge of the day into some kind of consistent system. Our own names of the planets, as handed down to us through the Greeks and Romans, are but the classical equivalents of the Babylonian deities.[596]
Jupiter is Marduk, the head of the Babylonian pantheon. Venus is the Babylonian Ishtar. Mars is Nergal, the god of war and pestilence. Mercury is Nabu, the god of wisdom and the messenger of the gods, and Saturn is Ninib.
Among the astrological texts preserved, Ishtar-Venus figures more prominently than the other planets. The appearance of Ishtar during each month and for various days of the month was noted, and then interpreted, partly on the basis of past experience, but also by other factors that for the most part escape us. A tablet, furnishing omens derived from the position of the planet Venus and which may belong to the series 'Illumination of Bel,' deals with the periods of the disappearance of Venus as evening star, and her reappearance as morning star, and vice versa[597].
In the month of Tammuz (4th month) Venus disappeared on the 25th day at sunset, for seven days was hidden[598], and on the 2d day of Ab (5th month) was seen at sunrise. Rains in the land. Destruction of[599] ...
In the month of Adar (12th month) Venus disappeared on the 25th day at sunrise. For a year (?) weapons are wielded[600] (?), gold[599] ...
In the month of Marcheshwan (8th month), 10th day, Venus disappeared at sunrise, for two months and six days was hidden, and reappeared on the 16th day of Tebet (10th month). There will be abundant crops.