Time-lapse photograph showing the setting sun at 5-minute intervals. In the foreground is the dome of the 4.2 metre (165-inch) William Herschel Telescope at the Roque de los Muchachos Observat- ory on La Palma, in the Canary Islands. The observatory is at an altitude of 2400 metres (8000 feet). Commissioned in 1987 & operated by the Royal Greenwich Observatory, the Herschel is the world's third largest single-mirror telescope.