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.
C/1807 R1
For this comet there were observational data for over six months and thus for a significant part of the cometary orbit Bessel's calculated predictions could be compared to the observations. The great comet of 1807 is the first long-period comet (other than Halley's comet, which was already known to be periodic) for which there is empirical verification that it moves in an elliptical, and not in a parabolic, orbit.