Starry Messenger

Sidereus Nuncius

Title page of the first edition.
Author	Galileo Galilei
Country	Republic of Venice (now Italy)
Language	New Latin
Subject	Astronomy
Publisher	Thomas Baglioni
Publication date	March 13, 1610

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 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, 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.

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." Therefore, the correct English translation of the title is Sidereal Message (or often, Starry Message).

A copy of the original edition is a valuable rare book and as of December 2010 has sold at auction for USD $662,500, including premium.

Although it is unclear who built the first telescope, its invention is commonly credited to Hans Lippershey, a German-Dutch lensmaker. The telescope allows the user to view distant objects as if they were much closer and larger. Galileo was one of the first to use the telescope to view and describe celestial bodies. One of Galileo’s first "Optical Canons," as he referred to them, had 8-10 enlargements (8x to 10x linear magnification) and was made out of lenses that he had ground himself. This increased to the 20-enlargement telescope that he used to make the observations in Sidereus Nuncius.