Keeping cool at La Silla

This striking picture of the New Technology Telescope (NTT) was taken just after sunset at ESO's La Silla Observatory, located in the Norte Chico in outskirts of the Chilean Atacama Desert. The Moon has already begun its journey across the evening sky, and is shining brightly overhead. The Sun dips below the horizon to the left of the frame, soaking the clouds in a rich orange colour.

The warm glow of the last rays of sunshine are caught by the reflective surface of the NTT walls. The purpose of this metallic dome is to stop the telescope’s enclosure from heating up during the day. This would affect the telescope’s observations, as rising warm air and turbulence blur images and worsen the astronomical seeing.

It is not just the telescope's enclosure that is designed to reduce heat accumulation during the day; the concrete platforms and parking spaces around the site are all painted white to increase the amount of light reflected from their surface.