Kepler's supernova in Ophiuchus. Artwork and map of the stars in and around the constellation of Ophiuchus (centre), showing the supernova observed in 1604 by the German astronomer Johannes Kepler (1571-1630). Ophiuchus is here represented as a man holding a serpent. The supernova is the object labelled N in the man's right foot. A supernova is the explosive death of a massive star. At its peak brightness this supernova outshone all the planets except Venus. Together with the supernova observed by Tycho Brahe in 1572, this event challenged the idea that the heavens were an unchanging place. This artwork was published in Kepler's De stella nova in pede Serpentarii (1606, On the New Star in Ophiuchus's Foot).