9 October – On this day

Supernova 1604, also known as Kepler’s Supernova, Kepler’s Nova or Kepler’s Star, was a supernova that occurred in the Milky Way, in the constellation Ophiuchus.

Appearing in 1604, it is the most recent supernova to have been unquestionably observed by the naked eye in our own galaxy, occurring no farther than 6 kiloparsecs or about 20,000 light-years from Earth. Visible to the naked eye, Kepler’s Star was brighter at its peak than any other star in the night sky, with an apparent magnitude of −2.5. It was visible during the day for over three weeks.