Guiding lights to the stars

The ESO 3.6-m telescope sits perched at the summit of the La Silla mountain in the Chilean Atacama Desert, 2400 m above sea level, in this Picture of the Week. A part of ESO’s La Silla Observatory, this location provides conditions ideal for stargazing, and is home to the prolific planet-hunter HARPS, the High Accuracy Radial velocity Planet Searcher.

In the dry desert, the skies are clear, and there is rarely a cloud to obstruct the view. Far away from the nearest cities, the skies are dark. The faint green airglow towards the horizon is naturally caused by molecules in Earth’s upper atmosphere. Even the dim, warmly toned lights of the access road, seen at the bottom of the image, are designed to limit the amount of light pollution they produce.

At the top we see one of our neighbouring galaxies, the Large Magellanic Cloud, known as lafken, labken or künchalabken (“lagoon”) and rünanko (“water well”) in the Mapuche culture. This dwarf galaxy orbits around the Milky Way, our home galaxy.