14 antennas at the ALMA AOS

Fourteen 12-metre antennas are in position at the ALMA Array Operations Site (AOS), in this photo taken in May 2011. The AOS is located at 5000 metres altitude on the Chajnantor plateau. ALMA will start Early Science Operations with sixteen antennas around the end of September 2011, while construction will be completed around 2013. The ALMA main array will have fifty 12-metre antennas, while the Atacama Compact Array (ACA) will have four 12-metre antennas and twelve 7-metre antennas.