Pierre Petit, Von Bedeutung der Cometen und des Gestirns. Dresden, 1681. Beinecke Rare Book and Manuscript Library, Yale University.

The Cosmographicall Glasse

As the Augsburger Wunderzeichenbuch illustrates, cosmological occurrences such as comets were often interpreted as omens, portents, and bringers of disasters such as plague and pestilence. In his treatise on comets, Pierre Petit, a French astronomer and colleague of Descartes, argued that the supposed link between comets and plagues was nonsense.

In this engraving, astronomers observe the trajectory of a comet, aided by a variety of instruments and charts. The flies and locusts buzzing around them are symbols of the pestilence superstitiously associated with comets, but the brightly-burning candle which illuminates their work represents the light of reason.

Left: Galileo Galilei, Telescope. Italy, 1609/10. Reproduced by kind permission of the Museo Galileo, Florence. Right: Isaac Newton, Second Telescope. England, 1671. © The Royal Society.

The problem with any model of the cosmos before the seventeenth century was that it was necessarily speculative and hypothetical. Around 1609, however, Galileo made one of the earliest telescopes using leather, wood, and two glass lenses. Sixty years later, Newton made a telescope which would become the model for those of the present day. Telescopes like Galileo’s and Newton’s permitted astronomers unparalleled visual access to the heavens, and worked towards the development of a science in which empirical observation could prove or disprove many of the hypotheses of the past.

Left: William Cunningham, The Cosmographicall Glasse. London, 1559. Reproduced by kind permission of the Syndics of Cambridge University Library. Right: Anon., Armillary Sphere. Germany, early 17th century. © The Trustees of the British Museum, CC BY-NC-SA 4.0.

William Cunningham’s The Cosmographicall Glasse was one of the most lavishly decorated and expensively printed astronomical books of the period, pitched at wealthy gentlemen for whom a technical knowledge of the cosmos was becoming increasingly fashionable. The page shown here depicts the Greek god Atlas bearing the heavens in the form of an armillary sphere. Underneath him are lines from Book I of Virgil’s Aeneid, in which Atlas is referred to as a teacher of astronomy.

Armillary spheres modelled objects and concepts in the skies in a spherical framework of concentric rings. They usually included important astronomical reference points like the equinoctial, the ecliptic, and the tropic of cancer, but they also normally included the zodiacal signs: in the Renaissance, astronomy and astrology were not conceptually separated in the way that they are today.