Sunset at Chajnantor

Sun is setting over the stunning Mars-like landscape of the Chajnantor plateau, located at 5000 metres altitude in the Chilean Andes, some 50 km away from San Pedro de Atacama. In the picture, taken from a nearby 5300-metre hill known as “Cerro Chico” (literally, the “Little Mountain”) towards the south-east, the APEX telescope is visible. APEX is a 12-metre antenna, operating at millimetre and submillimetre wavelengths and it is the pathfinder experiment for ALMA, the Atacama Large Millimeter/submillimeter Array, currently under construction at the same site.