Astronomical Images : Frontispiece weighing up cosmological systems

Giovanni Battista Riccioli

Astronomical Images

Educated at Jesuit schools in Ferrara, Piacenza, and Parma, Giovanni Battista Riccioli (1598-1671) began teaching at the Jesuit College in Parma in 1632. His career also took him to Mantua and Bologna, where, like most Jesuit professors of his day, he taught a wide variety of subjects, including logic, natural philosophy, mathematics, and theology. Riccioli's publications were equally diverse and included not only astronomical texts, such as his Almagestum novum and Astronomia reformata (1665), but also his Geographia et hydrographia (1661) and various theological treatises. Riccioli's gigantic astronomical encyclopaedia was the literary and pictorial climax of Jesuit propaganda against heliocentric aspirations. Riccioli gave a detailed account of the different world systems and even sugÂgested his own semi-tychonic system. He supplemented his astronomical discussion and critique of the Copernican theory with a biblical refutation based on Jesuit exegetical consensus. The frontispiece is dominated by the virgin Astraea on the right, representing theoretical and cosmoÂlogical astronomy, and on the left, a hundred-eyed Argus as practical and observaÂtional astronomy. Astraea is shown holding a scale weighing Riccioli's system against the Copernican; and the Copernican system is found wanting. The Ptolemaic system, too, lies discarded on the ground in front of Astraea, as is a defeated but still hopeful Ptolemy. At the same time Riccioli's frontispiece carries deep theological implications, signalled by the abbreviated biblical quotations that it contains. Astraea is explicit about the immobility of the Earth and refers to Psalm 104: 5: 'thou didst fix the Earth on its foundation that it never can be shaken'. At the top of the frontispiece, the hand of God is ordering the World according to number, measure and weight, referring to the Wisdom of Solomon 11: 20, another classical topic. However, in the exegetical tracts, this rather innocent passage was closely linked to Daniel 5: 24-30, which describes the writing on the wall at Belshazzar's feast. There, the blasphemous King had 'been weighed in the balance and found wanting' and consequently was slain that same night. The dense web of references to biblical exegesis might not have been intelligible to a broad audience, but from the Jesuit point of view, the message was pretty clear: God himself had weighed the world systems and found that of Copernicus wanting. Although the frontispiece clearly showed the general acceptance of Galileo's non-theoretical observations on the top right ' the surface of the Moon, the moons of Jupiter, the tripartite shape of Saturn ' it was simultaneously a pictorial anti-Copernican manifesto.