La Silla Paranal Observatory
Northern Chile: La Silla, Paranal and Chajnantor.
ESO operates the La Silla Paranal Observatory, providing some of the world's largest and most advanced observational facilities at three sites in Northern Chile: La Silla, Paranal and Chajnantor.
The Very Large Telescope (VLT) at Cerro Paranal is ESO's premier site for observations in the visible and infrared light. All four unit telescopes of 8.2m diameter are individually in operation with a large collection of instruments.
They are equipped with state of the art instruments either built completely by ESO or by external consortia, with substantial contribution by ESO.
APEX, the Atacama Pathfinder EXperiment, is a collaboration between Max Planck Institut für Radioastronomie (MPIfR), Onsala Space Observatory (OSO), and the European Organisation for Astronomical Reseach in the Southern Hemiphere (ESO).
APEX has a suite of heterodyne spectrometers and wide-field bolometer cameras operating in most of the atmospheric windows from 0.2 to 1.4 mm.