Star trails over La Silla

A long exposure has captured the setting stars in a moonlit night in form of colourful star trails above La Silla telescope domes and inversion layer in the southern outskirts of the Atacama desert, Chile. The trails are notabely distorted at the horizon as seen in this telephoto view. This mirage is similar to other common mirage of astronomical object such as the moon or the sun when they are near the horizon; an optical phenomenon in which light rays are refracted and bent in the atmosphere to produce distorted or multiple images of the object. The European Southern Observatory's (ESO) site at La Silla has telescopes which observe at optical and infrared. The largest optical telescope has a mirror with a diameter of 3.6 metres. The high altitude of La Silla (2400 metres), the dark sky, and the clear air above it (reducing atmospheric distortions of incoming light), make the site an ideal location for astronomical observations.