Werner Landgraf
He also developed a method of eliminating systematic errors in positioning brighter comets that resulted in a more accurate prediction of the Halley's Comet. A recalculation of the path of Halley's comet to 2317 BC confirmed that the Greeks had already seen the comet on 466 B.C.
He discovered seven minor planets including 3683 Baumann, 4378 Voigt (named after Hans-Heinrich Voigt), 9938 Kretlow and 4349 Tibúrcio at ESO's La Silla Observatory in northern Chile.
Halley's Comet
The 374 AD and 607 approaches each came within 0.09 AU of Earth. The 684 AD apparition was recorded in Europe in one of the sources used by the compiler of the 1493 Nuremberg Chronicles; it is the oldest-known picture of a comet. Chinese records also report it as the "broom star". The 451 AD apparition was said to herald the defeat of Attila the Hun at the Battle of Chalons.
In 837, Halley's Comet may have passed as close as 0.03 AU (3.2 million miles; 5.1 million kilometres) from Earth, by far its closest approach. Its tail may have stretched 60 degrees across the sky. It was recorded by astronomers in China, Japan, Germany, the Byzantine Empire, and the Middle East. In 912, Halley is recorded in the "Annals of Ulster", which state "A dark and rainy year. A comet appeared."