This is why we call it the Extremely Large Telescope! This photo shows the massive structure that will hold the main mirror of our ELT. It was taken when the construction reached an important milestone: for the first time, the telescope’s structure was rotated horizontally by a few centimetres... by hand! Read more: https://www.eso.org/public/images/potw2627a/ 1/2 📷 ESO/Cimolai #astrodon #astronomy #astrophysics #space #science #engineering