APEX at Chajnantor

The Atacama Pathfinder Experiment (APEX) 12-m telescope works at sub-millimetre wavelengths, in the 0.2 to 1.5 mm range. It is located on the 5100 m high Chajnantor plateau in the Atacama Desert (Chile), probably the driest place on Earth. APEX is the pathfinder to the ALMA project. In fact, it is a modified ALMA prototype antenna and is located at the future site of the ALMA observatory.