T he Saros (named coined by Edmund Halley) is a period of approximately 6585.32 days (exactly 223 synodic months or about 18.03 years) over which a particular sequence of eclipses occurs in same order with nearly the same geometry and nearly identical eclipses.

The Saros Cycle has been known since ancient times and proved useful for predicting eclipses.

Saros Cycles begin and end with many partial eclipses producing dozens of central eclipses in-between with increasing and decreasing durations.

The Saros Cycle is useful for arranging eclipses into families with each series typically lasts 12 to 13 centuries and containing 70 or more eclipses.

Because of the +1/3 fraction of days in a saros, visibility of each eclipse differs at a given locale. So, the Earth rotates about eight hours or 120 degrees westward for successive eclipse paths in the same saros. After three saroses (about 54 years 34 days), the eclipse path returns to about the same region. Compare the 2006 March 29 (Libya) eclipse to the next or 2024 April 8 (Mexico) eclipse, about 120 degrees further west.

Saros 139 Has The Following Characteristics

First Eclipse: 1501 May 17 Last Eclipse:  2763 July 3 Saros Duration: 1,262.11 Years All Eclipses: 71 (100%) Partial : 16 (22.5%) Annular:  0 (0%) Total:     43 (60.6%) Hybrid:  12 (16.9%) (Annular/Total) Longest Total:   07m29s  (2186 July 16)* Shortest Total:  00m35s  (2601 March 26) Previous Total: 04m07s  (2006 March 29) Next Total: 04m28s (2024 April 8) (Member #30 out of 71) *Longest duration of totality for the ten millennia from 3999 BCE to 6000 CE or three seconds less than the longest predicted possible duration (7m32s)!

Saros Cycle 139. Animation of eclipse paths from first to last eclipse. Series begins with partial eclipses near one of Earth's polar regions ending with partial eclipses near opposite pole. Animation briefly pauses for total eclipse of 2024 April 8, 30th member of this series of 71 eclipses. (Click to enlarge animation)

Ref. Fred Espenak (Animation by Dan McGlaun, 2007)