A supernova has exploded in the galaxy M101 in the well-known constellation of Ursa Major. As of 23 May the star’s brightness is magnitude 11, so while you won’t be able to spot it as a new star just by looking up at the sky, amateur astronomers with medium-sized telescopes (say 150 mm and upwards) should be able to pick it out visually if they are accustomed to using the instrument. Read more