Galileo Galilei was an  Italian polymath. Galileo is a central figure in the transition from natural philosophy to modern science and in the transformation of the scientific Renaissance into a scientific revolution. His contributions to observational astronomy include the telescopic confirmation of the phases of Venus, the discovery of the four largest satellites of Jupiter, the observation of Saturn's rings (though he could not see them well enough to discern their true nature) and the analysis of sunspots. Known for his work as astronomer, physicist, engineer, philosopher, and mathematician. Galileo has been called the "father of observational astronomy.