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.
Edmond Halley
From an observatory he constructed on Saint Helena, Halley recorded a transit of Mercury across the Sun. He realised a similar transit of Venus could be used to determine the size of the Solar System. He also used his observations to expand contemporary star maps. He aided in observationally proving Isaac Newton's laws of motion, and funded the publication of Newton's influential "Philosophiæ Naturalis Principia Mathematica".
From his September 1682 observations, he used the laws of motion to compute the periodicity of Halley's Comet in his 1705 "Synopsis of the Astronomy of Comets". It was named after him upon its predicted return in 1758, which he did not live to see.