A Brief History of Halley's Comet

Edmond Halley was the first person to recognise that this comet was periodic. This discovery was made in 1705 after he had computed parabolic orbits for 24 comets observed from 1337 to 1698. His analysis of the list revealed the comets of 1531, 1607, and 1682 moved in almost identical orbits and were separated by intervals of roughly 75 years. From this information, he predicted the comet would next appear in 1758. Halley died in 1742. The comet that now bears his name was recovered on 1758 December 25, by Johann Georg Palitzsch (Prohlis, Germany), a German farmer and amateur astronomer. Following the return of 1758-1759, astronomers began trying to link Halley's comet to comets seen prior to the 1531 appearance. Ultimately, 23 previous appearances were identified, indicating the comet had been seen at every return going back to the year -239 (240 BC).