Galileo: The Telescope and Its Consequences

Galileo Galilei (1564-1642), born in Pisa and later a professor of mathematics at Padua, did not invent the telescope; the first patent application for a spyglass was filed in the Netherlands by Hans Lippershey in 1608. What Galileo did, on hearing of the device in 1609, was rapidly improve its design, grinding his own lenses to reach a magnification of roughly twenty to thirty times, and then turn it methodically and repeatedly toward the sky, publishing what he saw. That combination of technical skill and systematic astronomical use, rather than invention itself, made the telescope into a scientific instrument.