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Mathematical Treasure: Riccioli's New Almagest

Frank J. Swetz (Pennsylvania State University)

Giovanni Battista Riccioli (1598-1671) was an Italian Jesuit priest, an astronomer, and an experimental physicist. He was very much involved in the planetary motion theories of his time. In 1651, he published Almagestum Novum (The New Almagest). This book, containing much data, became very popular in Europe and remained a standard reference for many years.

The frontispiece shows an imaginative scene. The hand of God opens the Heavens, imparting knowledge, while cherubs occupied with astronomical activities stand aside. On Earth, two muses use a balance to compare Galileo’s heliocentric planetary theory with the modified heliocentric system proposed by Tycho Brahe. The Ptolemaic system (described in Ptolemy's Almagest) lies discarded on the ground. In the comparison, Brahe’s theory seems to impart more weight.

The images above are presented courtesy of the History of Science Collections, University of Oklahoma Libraries.

Index to Mathematical Treasures

Frank J. Swetz (Pennsylvania State University), "Mathematical Treasure: Riccioli's New Almagest," Convergence (May 2019)