What did Tycho Brahe publish about the new star of 1572?

In 1573, Tycho Brahe published his observations of the "new star" (a supernova that appeared in the constellation Cassiopeia in 1572) in a work titled De nova stella.1

Through his precise measurements, Tycho demonstrated that the object lay beyond the Moon and was situated among the fixed stars. This discovery was significant because it challenged the prevailing Aristotelian doctrine, which held that the heavens were perfect and unchanging. By proving that real changes could occur in the stellar realm, Tycho’s publication helped shift the scientific understanding of the universe and established his reputation as a prominent astronomer in Europe.21