15

ASTRONOMY

The mul.Apin

In the popular imagination, the Middle Eastern sky stretches upward, forever deep and forever clear. The blood-red evenings gradually fade into a night where each star glistens with its crisp light. Beyond, the desert silence is broken only by the crackle of wood fires and voices murmuring over coffee and roasted lamb. It is true, and romantics will pray that it remains ever so, that the Middle East can be exactly as this dream would have it. Quite often it can—if one can ignore the intrusion of rusty water trailers, battery-powered televisions, portable gas cookers, and roving military helicopters lopping past like predatory pterodactyls—quite often, but not always.

It is easy to forget that a very simple practical problem confronted the ancient astrologers at the very outset. How were they to view the first rising of the moon when the horizon was totally obscured by clouds, dust, or sandstorms? As one Assyrian astrologer laments, “They watched the Moon; the clouds were dense, and the Moon was not seen.”1

This was a crucial and critical difficulty, for in order to maintain control over the calendar—one of the major tasks accorded the astrologers—they needed to know, with some precision, the day and the time upon which the new moon would appear and initiate a new month.

There is a tone of defensiveness in various letters from the astrologers to the king, written to explain why they had not been able to ascertain the exact beginning of the month or the rising of a planet. One senses their relief when the astrologers were able to report that “when the Moon appears on the first day . . . the land will be satisfied.”2 In other words, the lunar month was in harmony with the calendar month. Their reactions are testimony to the political pressure they were under. The king required an accurate calendar; if the astrologers could not maintain this, then their status, their position at court, was under serious threat.

This constant pressure upon the astrologers was undoubtedly the major factor that stimulated the development of Babylonian astronomical techniques, for the only means by which the astrologers could overcome the incertitude presented by the practical difficulties of observation was by devising an effective means of calculating, in advance, the first appearance of the new moon. In this way they could, also in advance, decide whether it was necessary to intercalate an extra month and so bring the civil calendar back into harmony with the lunar. Naturally, in order to do this they needed to gain an understanding of the cyclical movements, at least, of the sun and moon.

The technical advance necessary for this could not occur in a single stage. First, the celestial movements needed to be plotted accurately in order to build up sufficient data to make the existence of stellar cycles apparent. For this task the question of stellar location becomes crucial. Movement can be plotted only in relation to something fixed. Thus, the moon and planets needed to be located in space relative either to some geometrical constant—such as the ecliptic—or to the fixed stars. Some form of celestial cartography was needed.

Initially, in the early second millennium BCE, stellar geography was a very primitive affair. In the Venus Tablet of Ammisaduqa, this planet was located no more accurately than by its proximity to the horizon. But with time the means of location became more sophisticated. The astrologers writing to the royal court in the first millennium BCE would often relate planets to each other, to the moon, or to the fixed stars or constellations. In addition to this a certain amount of rudimentary relative measurement was demonstrated, using as measures of stellar distance “fingers” or “cubits”: “Mars . . . has approached one hundred and fifty cubits nearer to the constellation Libra,” for example.3

By means of their primitive timekeeping and constant observation, the astrologers eventually discovered the long-term movements of the sun, moon, planets, and stars, thus allowing them to begin to predict their future positions. No specific date can be placed upon this important discovery, but evidence within the tablets themselves would place it near the end of the second millennium BCE.

Nevertheless, many difficulties remained, not the least being the difference in viewpoint between Babylonia and Assyria. Because of the 4 degrees difference in latitude between the two cities, a planetary rising could be seen in Babylon before it was visible in Nineveh. This was no doubt the cause of the rather defensive letter from an astrologer in Nineveh to King Esarhaddon:

As regards the planet Mercury . . . “I have heard it can be seen in Babylon,” he who wrote this to the king, our lord, may really have observed it. His eye, however, must have fallen on it. We ourselves have kept watch but we have not observed it. One day it might be too early, the other day it might lie flat in the horizon. Our eyes should indeed have fallen on it.4

Gradually Mesopotamian science progressed until the astrologers were able to predict these events in advance. But even then perfection eluded them: “When the Moon out of its calculation delays and does not appear . . .” begins one rather sad explanation.5

Apart from the aesthetic or scientific considerations, an accurate calendar was important for agriculture in order that farmers might know precisely when the seasons began. When at an early stage the calendar remained erratic, with no noticeable regularity about the interpolation of intercalary months, the calendar could not be relied upon to indicate the beginning of the various seasons correctly. In other words, when the calendar said it was spring, it might, in fact, still have been winter—or just as easily summer. In consequence, farmers, in order to be certain about the seasons, did not rely upon the civil calendar but instead depended upon changes in the weather and watched for the rising of certain stars and constellations. The usefulness of these as markers for the seasons must have been realized very early. The fifth tablet of the creation myth, the Enuma Elish, begins with the determination of the astronomical boundaries for the year: “Marduk,” it states, “determined the year, defined the divisions; for each of the twelve months he set up three constellations.”6 A similar procedure was recognized by the ancient Greeks: the poem attributed to Hesiod, “Works and Days,” contains a number of these stellar markers for agricultural use.*36

These sets of constellations were standardized into four groups and recorded on tablets now known as the astrolabes. A number have survived, the earliest dating from around 1100 BCE.7 On these the stars are listed in three columns, each column holding twelve stars. For each month three stars are listed—one star each for the paths of Ea, Anu, and Enlil.8 Originally, it is thought, these were recorded upon a circular table divided into twelve segments and three concentric circles, thus giving thirty-six sections, each containing one star.

Each of the thirty-six sections not only listed the star but also held a number. Archaeologists pondering upon their significance soon realized that these numbers were related in some manner to the length of the day. It was finally discovered that they gave the weight of water that should run out of a water clock during the period of day or night. The highest number recorded was four, and this was associated with the rising of Orion in month three, which was summer. Thus, in summer four mana of water—around four pounds—would run out of the water dock during the day, whereas in month nine, which would be winter, only two mana were recorded as necessary.9

By later standards these astrolabes were not very accurate, but they clearly fulfilled a need and were produced over a long period; examples have survived from both Assyria and Babylonia ranging over a span of one thousand years. Yet, despite their evident success, the desire for more accuracy remained.

Greater accuracy was difficult in the period before mathematical techniques were introduced into astronomy. The practical instruments that the astrologers employed to supplement their observation of the heavens remained very rudimentary: a water dock to calculate the passing of time and a gnomon or sundial that marked the change in the year by means of the changing length of its shadow.

The water dock was very simple and measured time relative to a given weight of water. The Babylonian and Assyrian astrologers must have used a system similar to the later Greek and Roman timepiece called a clepsydra. Designs differed, but essentially it comprised a vertical container holding water that slowly ran out of a small hole at the bottom into a larger bowl equipped with a wooden float. As the water passed into the bowl, the wooden float rose up its side, which was marked with the hours.*37

The accuracy of the astrolabes was improved during the years preceding the turn of the first millennium BCE. The sum total of astronomical knowledge at this time was contained in a two-tablet compilation called, from its opening line, the mul.Apin.†38 The astronomy contained in the tablets has been shown to date from 1000 BCE or earlier by Professors Reiner and Pingree at Chicago’s Adler Planetarium.10 However, of the forty different examples of the text known—none complete in itself—only two contain a date, the earliest being from 687 BCE. This, then, in the absence of any further information, must mark the earliest point at which we can be certain that the information had been arranged into this compilation.

The mul.Apin consists of astronomical information placed under a number of groupings. Curiously, though, while this information obviously comes from elsewhere and has been brought together in the mul.Apin probably for the first time, there is little indication about these sources. It is difficult to believe that all previous texts were destroyed once the mul.Apin was compiled, but it is just as difficult to believe that none of these sources has been found in the various specialist libraries that have so far provided today’s scholars with raw material. Once again, we are confronted with an area needing further research and discovery.

The mul.Apin is grouped into eighteen sections. These include a list of fixed stars divided into those of the paths of Ea, Anu, and Enlil; the dates when the thirty-six fixed stars and constellations rise in the morning; the planetary periods; the seasons, equinoxes, and solstices; tables of the period of the moon’s visibility; rules for intercalation; gnomon tables detailing shadow lengths; and weights of water for their clocks. The tablets also contain omens drawn from comets and fixed stars.11

There is one further section contained in the tablets that is perhaps the prototype of an important later astronomical concept. The mul.Apin gives a list of all the stars in the “path of the moon,” that is, stars that lie in the apparent path along which the moon moves through the sky. As Professor Bartel Leendert van der Waerden notes, “the text states explicitly that not only the Moon, but also the Sun and other planets move in the ‘Moon’s path’ defined by these constellations.” The list of eighteen constellations is given in the text.12 It seems that this number of constellations used to mark the “moon’s path” gradually fell to twelve—the same twelve that later became the signs of the zodiac.

The “moon’s path” was a zodiacal belt 12 degrees wide within which the sun, moon, and planets all moved. While the zodiac as a regular mathematical division of the sky was not yet established, this concept of a celestial “path” probably represents the final stage before its invention. Perhaps all that remained was to formulate the ecliptic—the center of this belt—a line marking the apparent path of the sun.

The second-century CE astronomer and astrologer Claudius Ptolemy writes that he had access to eclipse records dating from the era of Nabonassar, king of Babylon from 747 to 734 BCE.13 However, he complains about the lack of reliable planetary data. He remarks that the ancient observations were made with little competence because they were concerned solely with the appearances and disappearances of planets and stars, all of which, he laments, were difficult to observe.14

Despite the apparent confidence in astrology, astronomical observation, and prediction as exemplified by the Enuma Anu Enlil and the mul.Apin, doubt obviously still remained. Astrologers were, it seems, seeking greater accuracy in their predictions from the omens and in their maintenance of the calendar. Perhaps they were driven by fear of the king, or maybe they were compelled by that obsessive curiosity that companions the intellectual process itself. Whatever the cause, the astrologers effected a remarkable and astounding change of perspective. They began, as it were, at the beginning. They began as if nothing could be taken for granted any longer. They began to compile the “diaries,” the nasaru sha gine, or the “regular watching.”

These texts record, in a systematic manner, both celestial and terrestrial events, and list, for periods ranging from several days to several months, all the major events observed in the heavens, the sky, society, commerce, and politics. There are two basic types of diary. Some were the “short diaries,” so called because they were used by the professional observers to record their regular daily observations. These cover short periods of under a month. By physical variations in their inscriptions they reveal that the same tablet was used night after night. In order to inscribe the small day tablets they needed to be kept soft and malleable. The usual process adopted by the scribes was to wrap the tablets in wet cloth, which delayed the process of drying. Some obviously began to harden prematurely because on these the final lines of cuneiform text are scratched onto the surface rather than being inscribed with the wedge-shaped impressions of the stylus.15 Once written, these short texts then served as raw data for the compilation of the larger and more elegant summaries that covered longer periods of up to a year.

Each diary records the length of the month and the details of the evening upon which the crescent moon is first visible. They contain other details about lunar events, the first and last appearance of the planets, their stations, and, in the later diaries, the relevant zodiacal signs. Dates of equinoxes and solstices were also listed, together with records of the appearances of Sirius. Then all other astronomical phenomena that struck the scholars as significant were added: the conjunctions of the moon and planets with fixed stars or less regular events, such as the appearance of comets or meteors.

Less exalted information was also recorded: the weather, for instance, together with wind direction and strength and the level of the river. The world of ancient commerce also found a place: written at the end was the market price—the amount that could be purchased for a shekel of silver—of such basic commodities as barley, dates, sesame, and wool, together with any price changes that occurred during the months in question.

The same tablets also listed the zodiacal placement of the important planets for those months and the political events—battles, deaths, treaties—that had taken place, albeit with an emphasis upon events in Babylon, the city in which all the diaries we have were written. In addition to all this information, they also recorded any unusual natural occurrences, an earthquake, for example, or something as mundane yet as ominous as a fox having run through the gate into the city.16 These diaries represent an important window upon ancient life.

The earliest known diary is represented by a fragment dating from 652 BCE, during the reign of Ashurbanipal.17 The next, a later copy of the presumed original text, bears the date “Year 37 of Nebuchadnezzar,” which is 568 BCE, almost a hundred years later.*39 A hundred and fourteen years more pass before the next appears, in 464 BCE. Only three more are represented that century. But, starting with a diary of 392 BCE, their numbers increase significantly, and many more are found, until the last, which is dated at around 60 BCE.18 In all, about 1,200 of these texts and fragments of texts exist, the preponderance being in the British Museum, which purchased the majority in the nineteenth century from antiquities dealers in Baghdad.

It is unlikely that the diary of 652 BCE represents the first and only time that century that such information was recorded. It must surely be viewed rather as an example of an established genre rendered unique solely by the caprice of history. While it is true that there is a gap of almost a century before the second example appears, this in no manner precludes the possibility that diaries once existed for all or many of the intervening years. In fact, it is more likely that the form was well established in Ashurbanipal’s time and continued, so far as was possible, in a systematic manner until the ultimate demise of the temple organization responsible for both the daily observations and their recording.

The overwhelming impression given by these diaries is that they represent an attempt to create a database. Indeed, what other rationale could there be for the methodical and detailed recording of all this information? It seems reasonable to suggest that these diaries indicate how, over the course of time, the astrologers had reoriented astrology and added new and more specific techniques to it, finally arriving at the point where they found the loose and nonmathematical Enuma Anu Enlil obsolete and primitive. To put it plainly, I suggest that the astrologers were aware that they had inherited a predictive tradition that was faulty. While the tradition itself had sufficient intellectual momentum, credibility accorded by its antiquity, and apparent practical value to justify their maintenance of it, they were aware of the need to revitalize it. Perhaps they were, in a way, embarking upon a search for connections that might exist between planetary and terrestrial events. Were they, I wonder, beginning to reject the cosmological ideas of their own tradition in favor of a more deterministic approach?

Whatever the causes, do not think it too fanciful to suggest that the implication of these diaries is that they represent evidence of a methodical attempt to collect data in order to seek some empirical link between celestial and terrestrial events, with the probable aim of eventually codifying these links and creating a new, “modern,” scientifically and mathematically rational astrological corpus—a new Enuma Anu Enlil perhaps?

It is evident that the seventh century BCE was a time of intense activity and discovery by the Assyrian and Babylonian astrologers, and further, that all the elements were in place both for the entry of mathematics into astrology and astronomy and for the discovery of the regular zodiac and the natal birth chart. All that was needed was some catalyst, some new perspective that could initiate these potential changes lying dormant beneath the surface. That catalyst was to appear in the sixth century BCE in the form of an invading army. Babylon was to be conquered by the Persians.