Giovanni Battista Riccioli
(17 April 1598 – 25 June 1671) was an Italian astronomer
and a Catholic priest
. He was a Jesuit
who entered the order in 1614. He was also the first person to measure the rate of acceleration of a freely falling body.
Riccioli was born in Ferrara
. He devoted his career to the study of astronomy, often working with Francesco Maria Grimaldi
. He wrote the important work Almagestum novum
in 1651. By necessity, he opposed the Copernican heliocentric theory
though praising its value as a simple hypothesis.
He and Grimaldi extensively studied the Moon, of which Grimaldi drew a map. Much of the nomenclature of lunar features still in use today is due to him and Grimaldi. He also observed Saturn
, and was one of the first Europeans to note that Mizar
was a double star
Despite his stated opposition to Copernicus's theory he named the prominent lunar crater Copernicus
after him, and other important craters were named after other proponents of the theory Kepler
. Craters that he and Grimaldi named after themselves are in the same general vicinity, while some other Jesuit astronomers have craters named after them in a different part of the Moon, near Tycho
. This is sometimes considered to be tacit sympathy for Copernican theory, which as a Jesuit he could not publicly express.
Between 1644 and 1656, he was occupied by topographical measurements, working with Grimaldi, determining values for the circumference of Earth
and... Read More