Christen Sørensen Longomontanus

Christian Severin ( Latinized Longomontanus, Danish Christian Sørensen, born October 4, 1562 Long Mountain, Jutland, Denmark, † October 8, 1647 ) was a Danish astronomer.

In 1589 he was hired by Tycho Brahe for astronomical observations. From 1597 to 1602 studied at the Universities of Severin in Breslau, Danzig, Königsberg and finally Rostock, where he received his doctorate in 1598 for Master. In 1603 he became rector of the school of Viborg. In 1605 he was elected professor at the University of Copenhagen, where he served four times as rector.

The lunar crater Longomontanus is named after him.