Which astronomer published the heliocentric model in De revolutionibus orbium coelestium in 1543?

Nicolaus Copernicus published the heliocentric model in De revolutionibus orbium coelestium in 1543.

Copernicus was a Renaissance mathematician and astronomer from Royal Prussia. His major work argued that Earth rotates on its axis and travels around the Sun, rather than occupying a stationary position at the centre of the cosmos. The book appeared in Nuremberg near the end of his life.

The model challenged the long-established geocentric system associated especially with Claudius Ptolemy. Copernicus still used circular orbits and epicycles, so his system was not the modern account of planetary motion. Its importance was that it reorganized the known motions around a Sun-centred framework.

Later astronomers supplied crucial improvements. Johannes Kepler replaced circular orbits with elliptical ones, Galileo's telescopic observations supported aspects of the new astronomy, and Isaac Newton explained planetary motion through gravitation. Copernicus therefore began a scientific transformation rather than completing it alone.

A common mix-up credits Galileo with inventing heliocentrism. Galileo defended and observed evidence for the model decades later, while Copernicus published the foundational mathematical proposal in 1543.