Concept
Sidereus Nuncius (usually Sidereal Messenger, also Starry Messenger or Sidereal Message) is a short astronomical treatise (or pamphlet) published in Neo-Latin by Galileo Galilei on March 13, 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, of hundreds of stars not visible to the naked eye in the Milky Way and in certain constellations, and of the Medicean Stars (later Galilean moons) that appeared to be circling Jupiter. The Latin word nuncius was typically used during this time period to denote messenger; however, it was also (though less frequently) rendered as message. Though 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." The first telescopes appeared in the Netherlands in 1608 when Middelburg spectacle-maker Hans Lippershey tried to obtain a patent on one. By 1609 Galileo had heard about it and built his own improved version. He probably was not the first person to aim the new invention at the night sky but his was the first systematic (and published) study of celestial bodies using one. One of Galileo's first telescopes had 8x to 10x linear magnification and was made out of lenses that he had ground himself. This was increased to 20x linear magnification in the improved telescope he used to make the observations in Sidereus Nuncius. Sidereus Nuncius contains more than seventy drawings and diagrams of the Moon, certain constellations such as Orion, the Pleiades, and Taurus, and the Medicean Stars of Jupiter. Galileo's text also includes descriptions, explanations, and theories of his observations.
