Saros Series

Definition

A Saros series is a family of geometrically related eclipses that recur about every 18 years, 11 days, and 8 hours — the Saros period of 223 synodic months ≈ 242 draconic months ≈ 239 anomalistic months. A series begins near one pole as a partial eclipse, walks across the Earth as the node line drifts, peaks as a run of total eclipses near the equator, and ends as partials near the opposite pole — spanning roughly 1,200–1,500 years and producing 69–87 eclipses.

In Tradition

In modern Western practice, eclipses within the same Saros series are treated as a thematic family: their near-identical Sun-Moon-node geometry recurs every Saros, giving each series a distinctive “character” read across its lifetime. Bernadette Brady popularised the convention of typing each series by the chart of its initial eclipse and reading subsequent members as continuing that family theme, layered over the per-eclipse chart of any given member.

In Practice

Practitioners identify a given eclipse’s Saros number from a standard table (van den Bergh; NASA / Espenak), then look up Brady’s thematic characterisation of that series. The series character is read as a slow-running storyline of which the present eclipse is one chapter. In a natal context, the prenatal eclipse degree carries the natal’s own Saros family forward; transits to the eclipse degree activate that family’s themes. In mundane work the same Saros across centuries is tracked through political and historical record. Saros context supplements rather than replaces the per-eclipse chart and mundane-path readings.

Historical Origin

The 18-year eclipse periodicity is documented in cuneiform astronomical sources. Francesca Rochberg’s *The Heavenly Writing* (CUP 2004) treats the Babylonian Saros as one of the period-relations underpinning Mesopotamian eclipse prediction, and Hunger and Pingree’s *Astral Sciences in Mesopotamia* document the 223-synodic-month period in System-A and System-B procedure texts. The name “Saros” was applied to the 18-year cycle by Edmond Halley in 1691 from a Greek source. Modern astrological use of Saros families derives from Bernadette Brady’s *Predictive Astrology*.

Etymology

Origin: Greek (via Babylonian). Meaning: Possibly from Babylonian saru (3,600) — adapted by Edmond Halley from a Greek source to name the eclipse cycle.

Further Reading

  • Bernadette Brady, Predictive Astrology: The Eagle and the Lark
  • Francesca Rochberg, The Heavenly Writing: Divination, Horoscopy, and Astronomy in Mesopotamian Culture
  • Hermann Hunger & David Pingree, Astral Sciences in Mesopotamia