Halley's Comet

A young English mathematician, Edmond Halley (1656-1742) took on the task of calculating the orbits of 24 comets. He published the results of his calculations in a dissertation entitled Astronomiae Cometicae Synopsis. In it he notably established that the comets observed in 1531, 1607 and 1682 were in fact a single comet with a periodic orbit. He predicted its return at the end of 1758 and the beginning of 1759, which turned out to be correct. The first periodic comet had just been discovered; Halley’s name was attributed to it. It has a periodicity of 76 years. Its last passage across our skies goes back to 1986, and its next will take place in 2061.