SN 1604, also known as Kepler's Supernova, Kepler's Nova or Kepler's Star, was a Type Ia supernova that occurred in the Milky Way, in the constellation Ophiuchus. Appearing in 1604, it is the most recent supernova in the Milky Way galaxy to have been unquestionably observed by the naked eye, occurring no farther than 6 kiloparsecs (20,000 light-years) from Earth. Before the adoption of the current naming system for supernovae, it was named for Johannes Kepler, the German astronomer who described it in De Stella Nova. Observation 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. Records of its sighting exist in European, Chinese, Korean, and Arabic sources. It was the second supernova to be observed in a generation (after SN 1572 seen by Tycho Brahe in Cassiopeia). No further supernovae have since been observed with certainty in the Milky Way, though many others outside the galaxy have been seen since S Andromedae in 1885. SN 1987A in the Large Magellanic Cloud was visible to the naked eye. Evidence exists for two Milky Way supernovae whose signals would have reached Earth 1680 and 1870 – Cassiopeia A, and G1.9+0.3 respectively. There is no historical record of either having been detected in those years probably as absorption by interstellar dust made them fainter. The remnant of Kepler's supernova is considered to be one of the prototypical objects of its kind and is still an object of much study in astronomy. Controversies Astronomers of the time (including Kepler) were concerned with observing the conjunction of Mars and Jupiter, which they saw in terms of an auspicious conjunction linked in their minds to the Star of Bethlehem. However, cloudy weather prevented Kepler from making any celestial observations. Nevertheless, his fellow astronomers Wilhelm Fabry, Michael Maestlin, and Helisaeus Roeslin were able to make observations on 9 October but did not record the supernova. The first recorded observation in Europe was by Lodovico delle Colombe in northern Italy on 9 October 1604. Kepler was only able to begin his observations on 17 October while working at the imperial court in Prague for Emperor Rudolf II. The supernova was subsequently named after him, even though he was not its first observer, as his observations tracked the object for an