Past eclipses

EARLIEST ACCOUNTS OF ECLIPSES

For thousands of years, human beings have marvelled at lunar and solar eclipses. These spectacular events naturally took root in the collective imagination. Ancient civilizations that documented eclipses include the Assyrians, Babylonians, Chinese, Egyptians, Greeks, Indians, Mayans, Persians and Sumerians! An understanding of eclipses was seen as vital to the relationship between humanity and the divine. Each civilization appointed its own official skywatchers, who were often priests or priestesses. For those who recognized the periodic nature of eclipses, the next step involved trying to calculate when future ones would occur. Although some were apparently successful in their predictions (Thales of Miletus), there were also stories of failure (the unfortunate Hsi and Ho, who met with the emperor’s wrath). However, it can be hard to know whether such age-old claims are true. In any case, several ancient civilizations managed to interpret some of the principles that govern the timing of eclipses. This is especially true for lunar eclipses, which have been largely understood for millennia. On the other hand, accurately predicting solar eclipses requires a well-developed theory of the motion of celestial bodies. 

IMPROVED PREDICTIONS

Relying on Newton’s theory of gravity and Kepler’s laws of planetary motion, astronomers began making much more accurate predictions. By the end of the 18^th century, they could usually calculate the exact location and timing of an eclipse. Today’s powerful computers can calculate the details of eclipses for centuries into the future—and the past! This has made it possible to critically assess ancient accounts of eclipses and even correct the dates of events mentioned in historical records. Well-informed astronomers now eagerly await each new eclipse, ready to record as many observations as they can during the event. In 1973, one group of astronomers even borrowed a Concorde supersonic jet prototype to track an eclipse.