Orologio Astronomico

Very rare plate engraved in Padua by Giuseppe Pasinati in 1791 from a drawing by Anselmo Perelli, showing an astronomical clock.

The term astronomical clock is often used to refer to any clock that displays, in addition to the current time, information of an astronomical nature. This may include the position of the sun and moon in the sky, the age and phase of the moon, the position of the sun on the ecliptic and the current sign of the zodiac, sidereal time, and other data such as lunar nodes, useful in predicting eclipses, and a rotating celestial map. Astronomical clocks usually represent the solar system using a geocentric reference system. At the center of the dial is often a disk or sphere representing the earth placed at the center of the solar system. The sun is often represented by a golden sphere placed in rotation around the earth with a 24-hour period. These instruments are in accord with the pre-Copernican European cosmological view.

Anselmo Perelli was probably the son of Tommaso Perelli (Florence, June 21, 1704 - Arezzo, October 5, 1783), a famous Italian astronomer. Belonging to a family of the nobility of Arezzo, he was initiated by his father to study law at the University of Pisa after completing his studies of fine arts at the Jesuits in Florence. In 1769 the professor of Astronomy Tommaso Perelli, together with his help Giuseppe Slop published the first series of astronomical observations with the title: OBSERVATIONES SIDERUM HABITAE PISIS IN SPECULA ACADEMICA AB ANNO LXV VERTENTIS SAECULI XVIII AD ANNUM LABENTEM LXIX JUSSU ET AUSPICIIS R.C. PETRI LEOPOLDI.

Anselmo publishes the Osservazioni meccaniche di Anselmo Perelli sopra un suo circolo ossia, orologio astronomico intorno al giro del sole, e moto della terra: con un modo di trovare quanti gradi di longitudine possa aver oltrepassato un bastimento in mare. Ed alcune riflessioni sopra il sistema di Copernico... At Giuseppe Rosa, 1794.