1746-1826

Italian Astronomer

Guiseppe Piazzi was born in Ponte di Valtellina, Italy, in 1746. At the age of 18 he became a Theatine monk. While studying at colleges of that order throughout Italy, he developed a fascination with mathematics and astronomy. After serving as a professor of theology in Rome and, later, as professor of higher mathematics at the Academy of Palermo, Piazzi founded the government observatory of Palermo in 1791.

As the observatory's first director, he launched a lengthy project dedicated to updating existing star catalogues. Piazzi wanted to document precisely the exact number and astronomical position of several thousand stars. He soon demonstrated that most stars were in motion relative to the sun. His first compilation, published in 1803, included 6,784 stars. Eleven years later, he updated his list, publishing a second catalogue containing 7,646 stars. Both lists were awarded prizes by the Institute of France.

While working on his...