December - A place fit to unveil the mysteries of the cold Universe

This beautiful picture shows the last rays of sunlight bathing the Chajnantor Plateau in Chile’s Atacama region. The plateau is the home of the Atacama Pathfinder Experiment (APEX) telescope. From this remote place, 5000 metres above sea level, APEX studies the cold Universe.

Clusters of white penitentes can be seen on the ground around APEX. The penitentes (Spanish for penitents) are a curious natural phenomenon found in high-altitude regions.

APEX is a collaboration between the Max Planck Institute for Radio Astronomy (MPIfR), the Onsala Space Observatory (OSO) and ESO. Operation of APEX at Chajnantor is entrusted to ESO.

APEX’s 12-metre dish is based on a prototype antenna for another observatory on Chajnantor, the Atacama Large Millimeter/ submillimeter Array (ALMA).


ESO/B. Tafreshi (

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