Olof Petrus Hjorter (1696–1750), Uppsala professor of astronomy in 1732–1737 and after 1746, independently discovered comet C/1743 X1 five days after Klinkenberg. With Celsius {see planet  (4169)}, he discovered the magnetic nature of aurorae. He donated his library to the Uppsala Observatory, and it is still the rarest part of that collection. (M 36947) _ _.