Whose telescope changed astronomy forever?

In 1609, Galileo Galilei heard of a new Dutch invention — the telescope — and quickly built his own improved version. Turning it to the sky, he made a series of astonishing discoveries: mountains and craters on the Moon, the four largest moons of Jupiter (now called the Galilean moons), the phases of Venus, and countless stars in the Milky Way. His observations provided strong evidence for the Sun-centered model of the solar system proposed by Copernicus, challenging the established Earth-centered view and bringing him into conflict with the Church. Galileo is often called the father of observational astronomy and modern science.