Month Number

□ Dam from Column V. ACTH. p. 9 6-pt. linear fit, segment !, _same, segment 2 _ same, segment 3

[ Jata derived i'( r Babylon Table! S

Figure 7.8. The zigzag function found from data in Column F of Babylon Tablets (a) 5 and (b) 120. The functions are decidedly similar, despite the fact that these tablets demonstrate the methods of System A and System B, respectively. The Columns

F contain the lunar velocity, under the assumption of constant solar velocity (corrections in other columns were applied to get the "final" prediction).

Table 7.13. Analyses of columns of Babylon Tablets 5 and 120.

Tablet (Column)/parameters Mm Dm P

5 F 2.28467 1.963325 0.321345 2.123998 13.94424

5 DB 18.13333 7.06667 11.06666 12.60000 12.36889

5 F 15.95000 11.06666 4.88335 13.50833 13.95239

120 A 30.03306 28.17769 1.85537 29.10537 12.36913

120 DB 30.03306 28.17767 1.85539 29.10537 12.36912

120 F 15.26805 11.0847 4.18335 13.17638 13.94450

Figure 7.9. A final example of the zigzag function usage, Column F of Tablet 5.

that Babylonian planetary theory was less developed than was the lunar theory. The planetary tables are, first and foremost, a set of uniform computations of planetary positions (positions, that is, of specific planetary configurations), with no direct reference to ecliptic latitude, for instance.

However, this must be tempered by the circumstance that the precise method they used to do the calculations is not fully known. Neugebauer considers the relative difficulty of planetary motions and their lack of calendrical importance as the basic reasons for the relative neglect they received; nevertheless, Babylonian astronomers had a theory for the motion of each planet and which provided the dates and longitudes when the planets were at critical configurations. They also had the means to apply certain corrections to the tables to account for varying intervals of invisibility, a circumstance to which the celestial latitude contributes. In any case, the purpose of the tables seems to be clear: to provide the instants of important configurations.

Figure 7.10 demonstrates the phenomena among the changing celestial longitudes of the inferior and superior planets, respectively, and that of the Sun. See the description of the planetary phenomena in §2.4.2 and §2.4.3 to connect the geocentric to the heliocentric motions, to trace the corresponding positions in the orbit, and to see the modern terminology. Because notation can become confusing, we again describe the progression of the tabulated phenomena for Mercury and Venus, in Neugebauer's notation and terminology (italicized), with our annotations:

(1) First visibility in the east (r). This is a morning star configuration (west of the Sun) in retrograde motion (i.e.,

ecliptic longitude

superior conjunctio:

ecliptic longitude

time conjunction invisible

east sf west of Sun

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