Paranal mirror inspection

Optical Technician Ernesto Araya inspects the tertiary mirror, M3, of UT4 "Yepun" — one of four Unit Telescopes that comprise ESO's Very Large Telescope (VLT), situated at Paranal Observatory in northern Chile. All of the telescopes' mirrors must occasionally be recoated to ensure the best possible astronomical images. Here, M3 is photographed ahead of receiving a new coat of reflective aluminium.