"In this Discussion Kepler gives reasons for accepting Galileo’s observations—although he was not able to verify them from want of a telescope—and entirely supports Galileo’s views and conclusions, adducing his own previous speculations, or pointing out, as in the case of Galileo’s idea of earth-light on the moon, the previous conception of[ix] the same explanation of the phenomenon. He rejects, however, Galileo’s explanation of the copper colour of the moon in eclipses. Kepler ends by expressing unbounded enthusiasm at the discovery of Jupiter’s satellites, and the argument it furnishes in support of the Copernican theory." -Introduction

"Sidereus Nuncius (usually Sidereal Messenger, also Starry Messenger or Sidereal Message) is a short astronomical treatise (or pamphlet) published in New Latin by Galileo Galilei in March 1610. It was the first published scientific work based on observations made through a telescope, and it contains the results of Galileo's early observations of the imperfect and mountainous Moon, the hundreds of stars that were unable to be seen in either the Milky Way or certain constellations with the naked eye, and the Medicean Stars that appeared to be circling Jupiter.[1] The Latin word nuncius was typically used during this time period to denote messenger; however, albeit less frequently, it was also interpreted as message. While the title Sidereus Nuncius is usually translated into English as Sidereal Messenger, many of Galileo's early drafts of the book and later related writings indicate that the intended purpose of the book was "simply to report the news about recent developments in astronomy, not to pass himself off solemnly as an ambassador from heaven."[2] Therefore, the correct English translation of the title is Sidereal Message (or often, Starry Message)."--Wikiped, Nov/2014.

In 'The Sidereal Messenger of Galileo Galilei,' readers are presented with a seminal collection that stands at the crossroads of science and literature, showcasing the groundbreaking work of Galileo Galilei alongside the complementary contributions of Johannes Kepler. This anthology offers a rare glimpse into the galvanizing moments of early modern astronomy through the lens of its most pivotal figures, underscoring the variety of approachesranging from meticulous observational reports to fervent correspondencesthat together have laid the foundations of contemporary celestial studies. The dialogues within, rich in both empirical evidence and speculative inquiry, serve to highlight the dynamic interplay between observation, hypothesis, and the relentless quest for knowledge that defined the era. The contributing authors, Galilei and Kepler, bring forth a compelling narrative of intellectual kinship and divergent methodologies toward understanding the cosmos. From the comprehensive observations and telescopic discoveries of Galileo that shifted humanitys perspective of our place in the universe, to Keplers mathematically driven insights that led to the laws of planetary motion, this collection encapsulates an era of unparalleled scientific revolution. Embedded within their historical context, these works not only mirror the epochal shift from geocentric to heliocentric models but also embody the spirited discourse between contemporaries that propelled the advancement of space science. 'The Sidereal Messenger of Galileo Galilei' is not merely an anthology; it is an invitation to witness the unfolding of human understanding of space through the minds of its most visionary pioneers. Readersfrom students and scholars of the history of science to those with a casual interest in astronomywill find in these pages a wellspring of knowledge, inspiration, and a profound appreciation for the intersection of science, philosophy, and the literary craft. Exploring this collection promises not only a deeper understanding of the milestones of scientific inquiry but also an appreciation for the enduring curiosity that drives humanity to explore beyond the known.

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The Sidereal Messenger of Galileo Galilei: And a Part of the Preface to Kepler's Dioptrics Containing the Original Account

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.[20] 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.[21] 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.[21] 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. CONTENTSTo the Most Serene Cosmo De' Medici, The Second, Fourth Grand-Duke of TuscanyivThe Astronomical MessengerixIntroduction.1Galileo's account of the invention of his telescope.3Galileo's first observation with his telescope.4Method of determining the magnifying power of the telescope.5Method of measuring small angular distances between heavenly bodies by the size of the aperture of the telescope.6The Moon. Ruggedness of its surface. Existence of lunar mountains and valleys.8The lunar spots are suggested to be possibly seas bordered by ranges of mountains.13Description of a lunar crater, perhaps Tycho.15Reasons for believing that there is a difference of constitution in various parts of the Moon's surface.16Explanation 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.18Calculation to show that the height of some lunar mountains exceeds four Italian miles (22,000 British feet).22The faint illumination of the Moon's disc about new-moon explained to be due to earth-light.25Stars. Their appearance in the telescope30