Giuseppe Piazzi: the controversial discovery and loss of Ceres in 1801

Abstract

[Extract] Theatricality was hardly the forte of Giuseppe Piazzi (1746–1826), but the Italian monk and Director of Palermo Observatory could hardly have set the stage for a better drama. Just as the nineteenth century began, he discovered the eighth planet of the solar system. He named it Ceres Ferdinandea.

On that night of 1 January 1801, Piazzi was engrossed in updating a star catalogue by Francis Wollaston (see Section 2.1.2) which was replete with inaccuracies. The catalogue had to be checked star by star, a task Piazzi was performing with a 1.5-metre vertical circle to determine star positions. For any particular star, Piazzi could observe it for only two minutes a night as it passed the meridian. At 8:43 pm local mean time, he saw a 'star' in Taurus that was not in the catalogue.