11 November
On 11 November 1572, Tycho Brahe, Danish nobleman and astronomer, discovered a new bright star in the constellation of Cassiopeia. This star, for the next two weeks, challenged all others in brightness. Although by the end of month it started to fade, it remained visible for the next 16 months.
After further study, dismissing that the event was in Earth's atmosphere, or even in our Solar System, Tycho Brahe wrote a small book called “De Stella Nova” from which we use the term “nova” even today. Until then, sky beyond Moon was thought to be unchangeable, so this event shook our current understanding of Universe.
This event probably had quite an influence on the young Tycho, who was just beginning of his career. He devoted the rest of his life to observing and measuring positions of stars and planets.
Today, this object is named SN 1572. It is visible only using infrared or x-ray telescopes.