	Nicolaus Reimers Baer (2 February 1551 – 16 October 1600), also "Reimarus Ursus", "Nicolaus Reimers Bär" or "Nicolaus Reymers Baer", was an astronomer and imperial mathematician to Emperor Rudolf II. Due to his family's background, he was also known as "Bär", Latinized to "Ursus" ("bear"). 