Tycho's supernova SN 1572

Timeline

1. 1572Various places in Central Europe (Wittenberg, etc.) · Holy Roman EmpireIn early November 1572 an unusually bright new star appeared in Cassiopeia, its brightness rapidly rising to rival Jupiter and Venus. Observers in Germany, Italy, and elsewhere recorded the phenomenon days before Tycho; most still interpreted it, within Aristotelian–Ptolemaic cosmology, as a combustion in the sublunar atmosphere or a comet-like change.
2. 1572–1573Helsingborg monastery · HelsingborgOn the evening of 11 November Tycho discovered the star at Helsingborg monastery and repeatedly measured its angular distances from neighboring stars using a sextant and other instruments. He proved the body had no diurnal parallax and kept a fixed position relative to the stars for months, so it was neither sublunar nor a planet but belonged to the sphere of fixed stars. This measurement made the new star key evidence against the doctrine of an unchanging heavens.
3. 1573Copenhagen · CopenhagenIn 1573 Tycho published De nova stella, releasing positional measurements, brightness variations, and natural-philosophy discussion, while criticizing those who still placed the new star below the lunar sphere. This short treatise made him famous among European scholars and became an important source of the reputation through which he later obtained royal patronage and established an observation base on Hven.
4. 1573–1574European astronomical community · EuropeThe new star gradually dimmed over the following year and disappeared from naked-eye view around spring 1574. Together with phenomena like the great comet of 1577, it forced European natural philosophers to reconsider whether the heavens could change. In his later Astronomiae instauratae progymnasmata Tycho continued to organize these observations; modern radio and X-ray observations confirm its remnant, and light-echo analysis supports the Type Ia classification.