Welcome to Atacama Pathfinder EXperiment (APEX)

Fifteen years exploring the dry southern skies over the Chajnantor plateau

Welcome to the APEX web site. You will find here all about our project and the amazing 12-m radio telescope that we operate in northern Chile. APEX is located in a privileged location, on the “Llano de Chajnantor”, at 5100 m. above the sea level. At such high altitude, the dry atmosphere of the Atacama desert opens up a unique window to observe the millimetre and sub-millimetre light. The versatile set of state-of-the-art instrumentation onboard APEX is at the service of researchers around the world, to learn more about the cold and the dusty Universe.