Galilei Galileo. Sidereus Nuncius or the Sidereal Messenger

Translated by Albert Van Helden — University Of Chicago Press, 1989 — 135 p. — ISBN 9780226279039, 0226279030.Galileo Galilei (1564-1642) published Sidereus Nuncius, or the «Starry Messenger» in 1610. In it he provided a lively and accessible account of his telescopic work: his observations of the Moon and, particularly, his discovery and observations of four satellites around Jupiter.
Galileo Galilei’s Sidereus Nuncius is perhaps the most dramatic scientific book ever published. It announced new and unexpected phenomena in the heavens, revealed by a mysterious new instrument. Galileo had ingeniously improved the rudimentary «spyglasses» that appeared in Europe in 1608, and in the autumn of 1609 he pointed his twenty-powered spyglass at the sky. This new instrument and Galileo’s brilliant use of it revealed astonishing sights: mountains on the Moon, fixed stars invisible to the naked eye, individual stars in the Milky Way, and four moons around the planet Jupiter. These discoveries changed the terms of the debate between geocentric and heliocentric astronomy and helped ensure the eventual acceptance of the Copernican planetary system. Furthermore, the telescope, as Galileo’s improved spyglass soon came to be known, was the first scientific instrument to amplify the human senses. This prototype of modern scientific instruments changed the practice of science forever.
This edition of Sidereus Nuncius is a new, complete, and extremely readable translation based on the original Latin text in the Venice 1610 edition. An introduction, conclusion, and copious notes place the book in its political, technological,religious, and intellectual context. Van Helden explains early spyglasses and the generally accepted beliefs about heavenly bodies that Galileo was soon to challenge. He relates how Galileo improved the spyglass and dealt for the first time with such now-familiar problems as optical imperfections, imperfect mountings, and limited field of view, and he quotes Galileo’s first letters reporting his findings.
The text of the «sidereal messenger» itself conveys both Galileo’s excitement and his careful methods, and Van Helden’s conclusion chronicles the public’s eager interest and flat disbelief, the skepticism about the telescope’s verity, the enthusiastic reaction of Johannes Kepler, the patronage of Grand Duke Cosimo II de Medici (whose name Galileo had given to Jupiter’s moons), eventual independent verification by other astronomers, Galileo’s subsequent observations of the shape of Saturn and the phases of Venus, and approval of both the telescope and Galileo’s discoveries by leading Jesuit mathematicians. Van Helden’s notes provide helpful elaborations and comments, explanations of terms, and references.
Albert Van Helden is professor of history at Rice University. He is the author of Measuring the Universe: Cosmic Dimensions from Aristarchus to Halley, also published by the University of Chicago Press.Sidereus nunciusThe reception of Sidereus nuncius