Professor Sinistra was a witch and member of the Astronomy department at Hogwarts School of Witchcraft and Wizardry. Sinistra taught her students at midnight at the topmost tower of Hogwarts Castle, and taught the names of stars and constellations, as well as the movements of the planets and other astronomical matters, and seemed to be a friend of the Substitute Professor for Care of Magical Creatures, Wilhelmina Grubbly-Plank.