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.
Thomas Bopp
Bopp later acknowledged the chance discovery, The following morning at 8:25am the office of Brian Marsden, director of the Central Bureau for Astronomical Telegrams, called him back to confirm the sighting was indeed a comet. The comet was given the formal name Comet 1995 O1, and three days later its full title C/1995 O1 (Hale–Bopp), designating the first comet found during the second half-month of July 1995. Hale's name precedes Bopp's because his was the first report to arrive. It is uncertain who was the first to discover it, as they both spotted it at around the same time. The following day Hale phoned Bopp to introduce himself with the words, "I think that we have something in common." When they met at a conference two months later, Bopp admitted to the press that Hale "turned out to be a nice guy."