Knowra Saros cycle Saros cycle The Saros cycle is a repeating sequence of solar or lunar eclipses separated by about 18 years, 11 days, and 8 hours. Each recurrence occurs when the Sun, Earth, and Moon return to nearly the same relative geometry.
Synodic month : The average interval between successive new moons or full moons, about 29.53 days. A whole number of synodic months returns the Moon to the same phase at a Saros recurrence.
Solar eclipse prediction : The calculation of when, where, and in what form a solar eclipse will occur. Saros recurrence identifies likely dates, while geometry is needed to predict each eclipse’s path.
Babylonian astronomy : The study and prediction of celestial phenomena in ancient Mesopotamia, especially through systematic observation and mathematical records. Babylonian astronomers recognized eclipse recurrences that underlie the Saros period.
Exeligmos : A period of three Saros cycles, about 54 years and 34 days, after which an eclipse occurs at nearly the same longitude. Unlike one Saros, an exeligmos nearly cancels the eight-hour shift in local time.
Saros series : A numbered sequence of solar or lunar eclipses separated by one Saros interval. The cycle is the interval that defines each successive member of a series.
Draconic month : The interval between successive passages of the Moon through the same orbital node, about 27.21 days. The near-integer count of draconic months brings the Moon back near an eclipse-producing node.
Lunar eclipse prediction : The calculation of when and how the Moon will pass through Earth’s shadow. Lunar eclipses recur in Saros series when full moons return near the same orbital node.
Babylonian eclipse records : Cuneiform records of lunar and solar eclipses observed or predicted by Babylonian scribes. These records document the practical discovery of recurring eclipse intervals.
Inex : An eclipse recurrence interval of about 10,571 days, linking eclipses near opposite lunar nodes. The inex connects eclipse families through a different interval and node relationship.
Saros number : An identifier assigned to an eclipse series, distinguishing it from other series of the same type. Numbering makes long Saros sequences easier to classify and compare.
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