Crab Nebula. Enhanced optical image of the Crab Nebula supernova remnant (M1, NGC 1952). This is the remains of a star which exploded as a super- nova in 1054 AD, an event witnessed by astronomers in China. It lies 6300 light years away in the constellation of Taurus. It is made up of gas ejected during the explosion, and by interstellar gas which has been swept up and ionised by the shock wave, causing it to glow. The Crab Pulsar, at the centre of the nebula (not visible), is the core of the exploded star. This image was produced by a CCD (charge-coupled device) camera, which stores images electronically rather than on film.