Halley's Comet of 1531 in the constellation of Leo from Petrus Apianus, Practica, 1531. Halley's Comet or Comet Halley (1P/Halley) is the best known of the short-period comets and is visible from Earth every 75-76 years. It was observed and recorded by astronomers since at least 240 BC. Records of the comet's appearances were made by Chinese, Babylonian, and medieval European chroniclers, but were not recognized as reappearances of the same object at the time. The comet's periodicity was first determined in 1705 by English astronomer Edmond Halley, after whom it is now named. Halley's Comet last appeared in the inner Solar System in 1986 and will next appear in 2061.