A supernova explodes 5 billion years ago

A supernova explodes 5 billion years ago. The figure shows a small field with three galaxies in the cluster AC 118, as observed with a CCD camera at the Danish 1.5 m telescope at La Silla on 31 August 1986 and 9 August 1988, respectively, under slightly different observing conditions. The image of the upper-left galaxy is extended downwards in 1988, due to the superposition of the supernova image, about 0.8 arcseconds southeast of the centre of the galaxy. The magnitude of the supernova is V 22.3; the redshift of the galaxy cluster is z = 0.31, corresponding to a recession velocity of km/sec. The supernova faded to on 16 August 1988. North is up and East is to the left. 1 pixel = 0.47 arcseconds. (ESO Press Release eso8807; BW)