Sculpting La Silla’s skies

A rare patch of wispy white clouds streak across the sky over ESO’s La Silla Observatory in this photograph, taken on 11 June 2012 by astronomer Alan Fitzsimmons.

This dry, desolate environment with occasional strong gusts of wind may not be the best place for people to set up home, but it is the ideal location for telescopes. Dry, arid conditions help astronomers to avoid common observing problems like atmospheric disturbance, light pollution, humidity, and (most of the time!) clouds, allowing them to gain a clearer view of the cosmos above. Even on this rare day of cloud the sky had cleared by nightfall and observations took place as usual.

The telescopes that call La Silla home — including two major ESO-operated telescopes: the ESO 3.6-metre telescope and the New Technology Telescope (NTT) — are equipped with state of the art instruments, enabling them to fully exploit the unique viewing conditions in northern Chile.

The ESO 3.6-metre telescope currently operates with the High Accuracy Radial velocity Planet Searcher (HARPS), an instrument that is dedicated to the discovery of extrasolar worlds. The NTT was a pioneer in active optics, and was the first telescope in the world to have a computer-controlled main mirror.

La Silla was the first ESO site to be based in Chile back in the 1960s, and has been invaluable ever since.