born Nov. 27, 1701, Uppsala, Swed.
died April 25, 1744, Uppsala
Swedish astronomer.
He taught at the University of Uppsala from 1730 to his death. In 1733 he published a collection of 316 observations of the aurora borealis. In 1744 he built the Uppsala Observatory. He is best known for his invention of the Celsius (often called centigrade) thermometer scale (1742), which set the freezing point of water at 0k and the boiling point of water at 100k.