Giuseppe Piazzi (Ponte in Valtellina, 1746 / Naples, 1826) was an Italian astronomer and clergyman, known for being the discoverer of Ceres and the founder of the Palermo astronomical observatory. Ordained as priest in 1764, he was professor of theology in Rome and of mathematics at the Academy of Palermo. He founded the Palermo Observatory in 1791, from where he made stellar catalogs (1803, 1814), he demostrated that the stars move with respect to the Sun and the motion of the double star 61 Cygni (1804). And also from this same observatory, the first day of the Nineteenth Century (January 1st, 1801), he discovered the dwarf planet Ceres, which was then considered a planet.
