June - VLT’s lasers and the stunning dark skies of the Atacama Desert

This photograph captures Unit Telescope 4 of ESO’s Very Large Telescope, located in Chile’s Atacama Desert, and its four-laser system, which is used to excite sodium atoms about 90 km up in the atmosphere. The atoms excited by the lasers emit light which is collected by the telescope at the same time as that of the stars. This emitted light is used by the adaptive-optics system to measure the distortions introduced by the atmosphere and then to correct for them. This advanced system, combined with the excellent dark-sky conditions of the Atacama Desert, ensures the telescope can obtain extremely sharp images.