Which Polish astronomer's Sun-centered model did Galileo publicly defend?

The Polish astronomer whose Sun-centered model Galileo publicly defended was Nicolaus Copernicus. Copernicus argued that Earth rotates on its axis and travels around the Sun, replacing the traditional Earth-centered arrangement associated with Ptolemy.

Copernicus presented the model in De revolutionibus orbium coelestium, published in 1543, the year of his death. Galileo did not simply repeat the theory: after beginning telescopic observations in 1609, he used discoveries such as the phases of Venus and the moons of Jupiter to challenge important arguments for a purely geocentric universe.

Galileo’s support became controversial because the Copernican system conflicted with influential interpretations of Scripture and with established Aristotelian natural philosophy. A common mix-up is Tycho Brahe, whose geo-heliocentric model placed the Sun around Earth while the other planets orbited the Sun; Galileo’s defended system was Copernican.