High above clouds over the Atlantic Ocean, a night begins for astronomers at the Roque de los Muchachos Observatory on the top of La Palma, 2400 meters above see level. The young moon appears on the right over the 4.2 m William Herschel Telescope. There are about a dozen major telescopes on this excellent observing site including the the 10.4 m GTC (Gran Telescopio Canarias) further away downhill in the middle left, Nordic Optical Telescope (NOT) and Swedish Solar Telescope at left.