Cat's Eye nebula. Hubble Space Telescope image of the Cat's Eye nebula (NGC 6543). This is a planetary nebula, shells of gas cast off by a dying star, whose light illuminates them. The star is seen at the centre of the nebula. The name is misleading, as planetary nebulae have nothing to do with planets. The structure of the gas shells is extremely intricate, and reveals much about the star and its slow death. The central regions show dense knots of gas amongst tangled streamers. The outer parts show concentric shells, cast off in 1500 year pulses. The Cat's Eye nebula lies around 3600 light years from Earth in the constellation Draco.