Opening a VLT dome at sunset

It is sunset at ESO´s Paranal Observatory. The four 8.2-metre Unit Telescopes (UTs) are being opened and readied for observations. The opening process is controlled by the engineer in charge (the UT manager) from inside the telescope dome. As part of the process, the telescope is tilted almost 90°, in order to minimise the risk that an object falling from the doors while they were opening could hit the mirror. Once the doors are opened, the telescope is typically returned to the vertical stand-by position and delivered to the astronomer and the instrument operator who operate it remotely from a control building located besides the VLT platform.