False-colour CCD optical image of the Hour-glass Nebula, which lies within the Lagoon Nebula. The nebula (purple) is a large cloud of gas which is lit up by ultraviolet light from the young star seen next to it (ring-shaped image). The photo was taken with a CCD (charge-coupled device) camera mounted at the prime focus of the William Herschel Telescope at the Roque de los Muchachos Observatory, La Palma.