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George von Rheticus was a well-known wizard astronomer and mathematician from Austria. Muggles know him as Georg Joachim von Rheticus, the sole pupil of Nicolaus Copernicus. During the time he spent with Copernicus, he made major contributions to both the Muggle and wizarding worlds by spreading Copernicus's works and inventing instruments that determined the length of day. Rheticus also had a passion for trigonometry. He released a tract named Canon of the Science of Triangles, which was the first ever publication of six-function trigonometric tables. His portrait has been relocated in Hogwarts castle several times. Like many other portraits, George von Rheticus hides secret passages. In 1991, the portrait was in the Grand Staircase and he stayed in the same spot until 1995 when the portrait was moved to hide a passage between the Grand Staircase and the seventh floor corridor. Within the same year, George von Rheticus was moved twice to the viaduct entrance and the second floor girls' lavatory. In the following year, the portrait was relocated yet again to the Entrance Hall where it hides a passageway to the portrait room. He hasn't been moved from his spot in the Entrance Hall since. George von Rheticus is known to be helpful and kind. He gives out directions to lost students, helps students with escaping detention, and he loves to have a chat about the stars. He is always ready to help a student in need as long as they are not a scoundrel. According to George, scoundrels are not good at astronomy.