Who were two famous astronomers during the renaissance?

Two of them Were 

Galileo Galilei, His contributions to observational astronomy include the telescopic confirmation of the phases of Venus, the discovery of the four largest satellites of Jupiter (named the Galilean moons in his honor), and the observation and analysis of sunspots. Galileo also worked in applied science and technology, inventing an improved the military compass, and other instruments.

Nicolaus Copernicus was a Renaissance mathematician and astronomer who formulated a model of the universe that placed the Sun rather than the Earth at the center of the universe