A village in the desert?

Located on the outskirts of the Chilean Atacama Desert, 600 km north of Santiago and at an altitude of 2400 metres, this seemingly tiny village in the middle of a desert is in fact ESO’s first observatory, the La Silla Observatory. 

The many astronomical facilities hosted at La Silla include ESO’s 3.6-metre telescope and ESO’s New Technology Telescope (NTT), as well as several national telescopes, such as ExTrA or the Danish 1.54-metre telescope.

The 3.6-metre telescope started operations in 1977. It is home to the High Accuracy Radial velocity Planet Searcher (HARPS), a powerful exoplanet hunter that discovered Proxima b — an Earth-mass rocky planet orbiting our closest neighbouring star after the Sun.

Inaugurated in 1989, the NTT constituted a major milestone in the field of active optics, a technique that adjusts the shape of a telescope’s mirror against distortions caused by the weight of the mirror itself. Using technology developed at ESO, the NTT was the first telescope in which such corrections were done in real-time during observations.

A village needs power, and La Silla’s photovoltaic plant delivers 1.7 MW using solar panels that stretch over 100 000 square metres in the desert. Thanks to this, all electricity used at the observatory during the day is renewable, preventing the emission of up to 400 tonnes of carbon dioxide equivalent every year. This is part of ESO’s wider efforts to reduce our environmental impact and operate our facilities in a more sustainable way.