Early Astronomy in the University of Michigan Collections

The Roundness of the Earth

This edition of Sacrobosco’s Sphaera mundi includes commentaries by Wenzel Faber von Budweis, an astronomer, astrologer, and theologian from Bohemia, who was well-known as a prolific author of the so-called practicas, yearly published booklets containing the astrological predictions of a particular year. Our copy has been heavily annotated by a contemporary reader.

Many editions of the Sphaera also include representations containing naturalistic elements such as this woodcut illustrating the roundness of the Earth. The image shows how the curvature of the earth produces a bulge in the ocean, which we would deceptively perceive as being flat. This bulge prevents the observer on the deck of the ship from seeing a point in the city, which is actually visible to the figure at the top of the mast.

Johannes de Sacrobosco

The Five Zones

Pre-Copernican Astronomy

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