Italianastronomer and monk. In 1789 he acquired a high-quality transit instrument made by the English optician Jesse Ramsden (1735–1800). From accurate positional measurements made with it, he compiled a star catalogue at the Observatory of Palermo, and in the process discovered the first asteroid, Ceres, on 1801 January 1. Piazzi's proposed term ‘planetoid’ lost out to F. W. Herschel's suggestion of ‘asteroid’.
Subjects: Astronomy and Astrophysics.