SAROS

in astronomy, interval of 18 years 11 1/3 days (10 1/3 days when five leap years are included) after which the Earth, Sun, and Moon return to nearly the same relative positions and the cycle of lunar and solar eclipses begins to repeat itself; e.g., the solar eclipse of June 30, 1973, will be followed by one of roughly the same latitude and duration on July 11, 1991. As the relative positions of the bodies are slightly changed after each saros, an eclipse cycle ends after a number of sarosesabout 71 for solar eclipses and 48 for lunar. Each saros contains about 43 solar and 28 lunar eclipses.