VLT´s UT2 mirror recoating

Preparations for the recoating the VLT's Unit Telescope 2 (Kueyen) primary mirror (M1). A special crane takes the M1 cell, which weighs 45 tonnes, out of the telescope building. The cleaning of the Very Large Telescope primary mirrors is a very delicate operation which takes place every 18 months and consists in removing the aluminium layer by chemical washing and then recoating the mirror.