Galileo's Telescope

Perhaps the most famous of Galileo's scientific instruments was the telescope. This photo features Galileo's original 1609 invention. It was modeled after telescopes produced in other parts of Europe that could magnify objects three times. His telescope could magnify objects twenty times. With his telescope, he was able to look at the moon, discover the four satellites of Jupiter, observe a supernova, verify the phases of Venus, and discover sunspots.

His discoveries provided observational proof of the Copernican system, which states that the earth and other planets revolve around the sun. Prior to the Copernican system, it was held that the universe was geocentric, meaning the sun revolved around the earth.