This Day In History: 1604-10-09
1604: Supernova 1604 is first sighted, the most recent supernova to be unquestionably observed by the naked eye within our galaxy, by Italian astronomer Lodovico delle Colombe. The German astronomer Johannes Kepler tracked it for a year, and it was for a time called Kepler’s Star. It was brighter at its peak than any other star in the night sky, with an apparent magnitude of −2.5. It was visible during daylight for over three weeks.