PREDICTIVE ASTRONOMYIt is, thus, all the more remarkable that accurate predictions of ominous phenomena
were eventually made, and by scholars whose livelihoods depended upon royal support
for celestial divination. We have been fortunate enough to have recovered many
hundreds of the letters (Parpola 1993 ) and reports (Hunger 1992 ) the Neo-Assyrian
scholars working in the entourages of the kings sent to their masters. Many included
extracts from Enu ̄ ma Anu Ellilthat best applied to the current state of the heavens,
some accompanied these with comments which show that the scholars were beginning
to make accurate astronomical predictions.^14 Still, as the scholar Balasî writes in a letter
to his king: ‘The god has (only) wanted to open the king’s ears. He should pray to the
god, perform the apotropaic ritual, and be on his guard’ (Parpola 1993 : no. 56 : r. 18 f)
revealing that celestial phenomena continued to be regarded in the highest circles as
the manifestations of the arbitrary will of the gods (or at least that is what the astrologer
wanted the king, who was after all financing him, to believe). We should not be surprised,
however, if, for some, accurate prediction could not sit easily with celestial divination,
and Brown has traced the evidence for this point of view in Mesopotamian sources
(Brown forthcoming a). In 2000 (239–43), Brown concluded that the reason for the
appearance of accurate prediction at this time was due to the particular circumstances
under which the Neo-Assyrian scholars worked, where being able to know in advance
when an ominously dangerous phenomenon would occur gave them a competitive
advantage over their colleagues in their dealings with the king.
Thus far, our evidence for Mesopotamian predictive astronomy derives from the
ca. 1 , 500 astronomical cuneiform texts recovered from Babylonia that date from c. 750
BCto AD 75 , and the occasional references to accurate astronomical calculation made
in the Neo-Assyrian letters and reports almost entirely from Nineveh. Our sources
for Assyria end around 612 BC, and those for Babylonia are scant in this regard until
the Hellenistic period. We have reason to suspect that the Neo-Babylonian kings
employed celestial diviners, as perhaps did the Persians after they conquered Babylonia
in 539 BC, though direct evidence is lacking. Nevertheless, enough has been recovered
from the temples to indicate that calculations of the dates and locations of planetary
phases based on an initial observation and a characteristic interval were being made
from the seventh century BConwards.^15 In 568 BC, an interval between Moonrise
and Sunrise, known as ‘kur’, was calculated according to the Diary preserved for that
year. It seems likely that this interval, summed with other similar luni-solar intervals,
was used in conjunction with a characteristic interval, after which their sum repeats,
to calculate the length of lunations, as elucidated by Brack-Bernsen ( 1997 ). The use
of characteristic intervals and initial observations to make astronomical predictions
continued until the very end of the cuneiform tradition. We refer to texts recording
predictions made on this basis as ‘non-mathematical astronomical texts’ and these
include the Diaries,^16 Goal-Year Texts, and two types of Almanac. The Goal-Year
Texts present, for a given year, data for the phases of the planets and their passing
by of certain stars that occurred a characteristic number of years earlier. For example,
after 59 years, Saturn repeats a given phase, say heliacal rising, at the same point in
the ecliptic. A Goal-Year Text thus includes 59 -year-old data on Saturn. The Almanacs
contain computations for the size of the various luni-solar phenomena, the dates of
the phases of the planets, the dates upon which the planets cross the boundaries from
— Mesopotamian astral science —