Mounted image 21: VLT Auxiliary Telescope
The four mobile 1.8-metre Auxiliary Telescopes (ATs) aid in interferometry at the Very Large Telescope at Paranal. The ATs are technological marvels. In their ultra-compact enclosures, they have an air-conditioning system, cooling liquid for thermal control, compressed air for enclosure seals, a hydraulic plant for opening the dome shells, and more. Each AT can move around in its own housing on the top of Paranal, almost like a snail.