The Face of the Moon

7. Riccioli, Giovanni Battista (1598-1671).

Almagestum nouum. -- Bologna: ex typographia haeredis Victorij Benatij, 1651.

The Riccioli moon map is historically of great importance, since it provided the basis for the system of lunar nomenclature still in use. It is more properly referred to as the Riccioli/Grimaldi map, since the Jesuit optician Francesco Grimaldi was apparently responsible for the map itself, while fellow-Jesuit Riccioli invented the names (and wrote the book in which the map appeared). Thus the Sea of Tranquility (Mare Tranquillitatis) traversed by the Apollo astronauts acquired its name here, as Mare Tranquillitatis, as did such prominent lunar craters as Plato, Ptolemaeus, and Tycho.

image - click to enlarge

Riccioli's assignment of some of the brightest craters to Copernicans--Kepler, Galileo, Lansberg, and Copernicus himself--has always been a bit of a puzzle, since as a Jesuit, Riccioli staunchly upheld the doctrine of a fixed and central earth. He claimed to have flung the heliocentrists into the Sea of Storms (Oceanus Procellarum), but some wonder if he did not reveal here a secret fondness for the Copernican doctrine, especially since he named two nearby craters Grimaldus and Ricciolus, while other Jesuit astronomers were assigned to craters in the south, surrounding Tycho.

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