The ESO headquarters are located in Garching, near Munich , Germany and it employs 570 personnel in Europe and Chile . Its aims and objectives: to explore where no ground based observatory has explored before and in order to do so it is foremost in the implementation of new technological advances.

Created in 1962, ESO provides state-of-the-art research facilities to European astronomers and astrophysicists. ESO operates the La Silla Paranal Observatory, located at several sites 2400 m high in the mountains, 600 km north of Santiago de Chile in the Atacama Desert region. It is one of the scientifically most productive observing sites in the world. It is equipped with several optical telescopes with mirror diameters of up to 3.6 meters. The 3.5-m New Technology Telescope (NTT) was the first in the world to have a computer-controlled main mirror.

Since 1999 however the 2600 m high Paranal site with the Very Large Telescope array (VLT) has become the flag ship of European Astronomy. The VLT is a most unusual telescope, based on the latest technology. It is not just one, but an array of four telescopes, each with a main mirror of 8.2-m diameter. With one such telescope, images of celestial objects as faint as magnitude 30 have been obtained in a one-hour exposure. This corresponds to seeing objects that are four billion times fainter than what can be seen with the naked eye.

The Atacama Large Millimetre Array (ALMA), one of the largest ground-based astronomy projects of the next decade, is a major new facility for world astronomy. ALMA will be comprised of a giant array of 12-m submillimetre quality antennas, with baselines of several kilometres. An additional, compact array of 7-m and 12-m antennas is also foreseen. Construction of ALMA started in 2003 and will be completed in 2012; it will become incrementally operational from 2010 on. ALMA is located on the high-altitude Llano de Chajnantor (5000 m elevation), east of the village of San Pedro de Atacama in Chile.