Nicolaus Copernicus (1473-1543) and Tycho Brahe (1546-1601) were two famous Renaissance astronomers.
Nicolaus Copernicus was a Renaissance-era mathematician and astronomer who developed a model of the universe placing the Sun rather than the Earth at the center of the universe.
Tycho Brahe was a Danish nobleman, astronomer, and writer noted for his accurate and comprehensive astronomical and planetary observations.