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

This photograph captures the 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 in the atmosphere. The atoms excited by the lasers emit light that is affected by the atmosphere in the same way as the light emitted by real stars. The emitted light is collected by the telescope and can be 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, ensure the telescope can obtain extremely sharp images.