The Sidereal Messenger (Illustrated Original Edition)

By Galileo Galilei

Galileo Galilei had seriously considered the priesthood as a young man, at his father's urging he instead enrolled at the University of Pisa for a medical degree. In 1581, when he was studying medicine, he noticed a swinging chandelier, which air currents shifted about to swing in larger and smaller arcs. It seemed, by comparison with his heartbeat, that the chandelier took the same amount of time to swing back and forth, no matter how far it was swinging. When he returned home, he set up two pendulums of equal length and swung one with a large sweep and the other with a small sweep and found that they kept time together. It was not until Christiaan Huygens almost one hundred years later, however, that the tautochrone nature of a swinging pendulum was used to create an accurate timepiece.To this point, he had deliberately been kept away from mathematics (since a physician earned so much more than a mathematician), but upon accidentally attending a lecture on geometry, he talked his reluctant father into letting him study mathematics and natural philosophy instead. He created a thermoscope (forerunner of the thermometer) and in 1586 published a small book on the design of a hydrostatic balance he had invented (which first brought him to the attention of the scholarly world). Galileo also studied disegno, a term encompassing fine art, and in 1588 attained an instructor position in the Accademia delle Arti del Disegno in Florence, teaching perspective and chiaroscuro. Being inspired by the artistic tradition of the city and the works of the Renaissance artists, Galileo acquired an aesthetic mentality. While a young teacher at the Accademia, he began a lifelong friendship with the Florentine painter Cigoli, who included Galileo's lunar observations in one of his paintings. Galileo Galilei’s Sidereus Nuncius is arguably the most dramatic scientific book ever published. It announced new and unexpected phenomena in the heavens, “unheard of through the ages.

CONTENTS

• To the Most Serene Cosmo De' Medici, The Second, Fourth Grand-Duke of Tuscanyiv
• The Astronomical Messengerix
• Introduction.1
• Galileo's account of the invention of his telescope.3
• Galileo's first observation with his telescope.4
• Method of determining the magnifying power of the telescope.5
• Method of measuring small angular distances between heavenly bodies by the size of the aperture of the telescope.6
• The Moon. Ruggedness of its surface. Existence of lunar mountains and valleys.8
• The lunar spots are suggested to be possibly seas bordered by ranges of mountains.13
• Description of a lunar crater, perhaps Tycho.15
• Reasons for believing that there is a difference of constitution in various parts of the Moon's surface.16
• Explanation of the eveness of the illuminated part of the circumfrence of the Moon's orb by the analogy of terrestrial phenomena, or a possible lunar atmosphere.18
• Calculation to show that the height of some lunar mountains exceeds four Italian miles (22,000 British feet).22
• The faint illumination of the Moon's disc about new-moon explained to be due to earth-light.25
• Stars. Their appearance in the telescope30

• Language: English
• Publisher: Balungi Francis
• Release date: Jan 5, 2021
• ISBN: 9791220246903

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telescope

To the Most Serene Cosmo De' Medici, The Second, Fourth Grand-Duke of Tuscany

There is certainly something very noble and large-minded in the intention of those who have endeavoured to protect from envy the noble achievements of distinguished men, and to rescue their names, worthy of immortality, from oblivion and decay. This desire has given us the lineaments of famous men, sculptured in marble, or fashioned in bronze, as a memorial of them to future ages; to the same feeling we owe the erection of statues, both ordinary and equestrian; hence, as the poet[1] says, has originated expenditure, mounting to the stars, upon columns and pyramids; with this desire, lastly, cities have been built, and distinguished by the names of those men, whom the gratitude of posterity thought worthy of being handed down to all ages. For the state of the human mind is such, that unless it be continually stirred by the counterparts[2] of matters, obtruding themselves upon it from without, all recollection of the matters easily passes away from it.

But others, having regard for more stable and more lasting monuments, secured the eternity of the fame of great men by placing it under the protection, not of marble or bronze, but of the Muses' guardianship and the imperishable monuments of literature. But why do I mention these things, as if human wit, content with these regions, did not dare to advance further; whereas, since she well understood that all human monuments do perish at last by violence, and invented more imperishable signs, over which destroying Time and envious Age could claim no rights; so, betaking herself to the sky, she inscribed on the well-known orbs of the brightest stars—those everlasting orbs—the names of those who, for eminent and god-like deeds, were accounted worthy to enjoy an eternity in company with the stars. Wherefore the fame of Jupiter, Mars, Mercury, Hercules, and the rest of the heroes by whose names the stars are called, will not fade until the extinction of the splendour of the constellations themselves.

But this invention of human shrewdness, so particularly noble and admirable, has gone out of date ages ago, inasmuch as primeval heroes are in possession of those bright abodes, and keep them by a sort of right; into whose company the affection of Augustus in vain attempted to introduce Julius Cæsar; for when he wished that the name of the Julian constellation should be given to a star, which appeared in his time, one of those which the Greeks and the Latins alike name, from their hair-like tails, comets, it vanished in a short time and mocked his too eager hope.