Demise in ice and fire   The Bug Nebula, NGC 6302, is one of the brightest and most extreme planetary nebulae known. At its centre lies a superhot, dying star smothered in a blanket of icy 'hailstones'. A new Hubble image reveals fresh detail in the wings of this 'cosmic butterfly'.   The Bug Nebula, NGC 6302, here imaged with the 3.6-metre telescope at ESO's La Silla Observatory by astronomer Romano L.M. Corradi. Release date: 29 April 2004