PIAZZI, GIUSEPPE (1746–1826), Italian astronomer, was born at Ponte, in the Valtellina, on the 16th of July 1746. He entered the Theatine Order in 1764, accepted the chair of mathematics in the academy of Palermo in 1780, and persuaded the Viceroy, Prince Caramanico, to build an observatory there. During a visit to England in 1788 he procured from Jesse Ramsden a five-foot altazimuth, with which he collected at Palermo, 1792–1813, the materials for two admirable star-catalogues, published in 1803 and 1814 respectively. While engaged on this work he discovered, on the 1st of January 1801, the first asteroid or minor planet, to which he gave the name of Ceres, the tutelary deity of Sicily. He d1ed at Naples on the 22nd of July 1826.
See B. E Marneri, L’Astronomo Giuseppe Piazzi (Milan, 1871); R. Wolf, Biographien, Bd. iv. p. 275; Monatliche Correspondenz (1810; portrait), xxi. 46; Astr. Jahrbuch, liv. 218; Bulletin des sciences (1826), vi. 339, Edin. Journal of Science (1827), vi. 193; Memoirs Roy. Astr. Soc. 111. 119; R. Grant, Hist. Phys. Astronomy, pp. 238, 510, 549.