View of Chajnantor plateau

The impressive extent of the Chajnantor plateau, located at 5000 m altitude in the Chilean Andes is captured in this view toward the west. Due to its elevation and its dryness, the Chajnantor plateau is one of the best sites on Earth for millimetre and submillimetre astronomy. ALMA is the most powerful radio observatory in the world operating at these wavelengths and the largest astronomical project in existence. The Array Operations Site (AOS), from where the 66 antennas of ALMA will be studying the Universe, is on Chajnantor, while the Operations Support Facility is located at the more comfortable altitude of 2900 m, along the same road to Chajnantor. Another submillimetre telescope, APEX, the Atacama Pathfinder Experiment, has operated on Chajnantor since 2005.