Goal-Year Periods

Definition

The Goal-Year Periods are the planet-specific whole-year intervals after which each planet's synodic phenomena recur in nearly the same calendar-and-longitude pattern. The canonical inventory is: Saturn 59 years; Jupiter 71 or 83 years; Mars 79 or 47 years; Venus 8 years; Mercury 46 years. The dual-value pair for Jupiter and Mars distinguishes the synodic return (71 / 79 years) from the sidereal return (83 / 47 years). They are the predictive intervals the Late Babylonian goal-year-text genre exploits.

In Tradition

Hunger-Pingree, Neugebauer, and Brown concur in treating the Goal-Year Periods as empirical period-returns rather than exact relations. Brown reads the Jupiter 71 / 83 and Mars 79 / 47 dual periods as evidence that the shorter values (sufficient for date-prediction) emerged first to serve divinatory need, while the longer values (more accurate for sidereal position) emerged later to serve zodiacal astrology.

In Practice

A Goal-Year Text predicts a planet's behaviour in a target ("goal") year by going back the planet's period and copying forward the synodic data — first/last visibilities, stations, retrogradations, Normal-Star passings — from that earlier year. The Jupiter section uses 71 years for the Greek-letter phenomena and 83 years for Normal-Star conjunctions; the Mars section uses 79 years for the Greek-letter phenomena and 47 years for Normal-Star conjunctions; Venus uses 8 years, Mercury 46, Saturn 59; the Moon section uses 223 months for eclipses and the Lunar Six, and 229 months for the šú+NA and me+gi6 sums. Hunger-Pingree and Brown both anchor the inventory in BM 45728, BM 41004 ("text E," Neugebauer-Sachs 1967), and LBAT 1285. Neugebauer observes that exactly these five planetary periods were taken over by Hipparchus and quoted by Ptolemy in Almagest IX 3 — a concrete vehicle of Babylonian-to-Greek transmission.

Historical Origin

Attested across the Seleucid-period Goal-Year Texts (Babylon and Uruk, c. 250-50 BCE), with the inventory recovered from BM 45728, BM 41004, LBAT 1285, and parallel tablets. Modern critical treatments: Hunger-Pingree, *Astral Sciences in Mesopotamia* (1999), Ch. II §B.5 pp. 185-186 and pp. 221-223; Brown, *Mesopotamian Planetary Astronomy-Astrology* (2000), §4.1.2 pp. 186-187; Neugebauer, *Astronomy and History: Selected Essays* (1983), essay [26] p. 323.

Further Reading

• Hermann Hunger & David Pingree, Astral Sciences in Mesopotamia
• David Brown, Mesopotamian Planetary Astronomy-Astrology
• Otto Neugebauer, Astronomy and History: Selected Essays