What was the sixteenth century astronomer who used mathematics?

The sixteenth-century astronomer who is well-known for using mathematics in his work is Nicolaus Copernicus. He proposed the heliocentric model of the solar system, which placed the Sun at the center rather than the Earth. Copernicus utilized mathematical calculations to support his theories, fundamentally changing the way we understand the universe. His seminal work, "De revolutionibus orbium coelestium," laid the groundwork for modern astronomy.