Copernican system

The only stipulation was that he had to describe the two models impartially, without arguing in favour of the Copernican system, and restricting himself to the astronomical and mathematical arguments on both sides.

As geometrical hypotheses, the Ptolemaic, Tychonic and Copernican systems were equivalent; but as astronomical hypotheses they were radically different.

The Catholic Encyclopedia takes the same position, stating that “Bruno was not condemned for his defense of the Copernican system of astronomy, nor for his doctrine of the plurality of inhabited worlds.”

Although he had no solid proofs of the motion of the Earth, Galileo argued persuasively, making it intellectually respectable to believe in the Copernican system.

For Digges, the star offered a potential confirmation of the Copernican system, and an opportunity to advance his reputation through timely publication of his own work on stellar parallax.