Signing the ELT position actuators contract

ESO Director General Tim de Zeeuw and Dr Karl Spanner from Physik Instrumente GmbH & Co. sign a contract to construct the position actuators (PACTs) that will adjust the positions of the 798 hexagonal segments of the primary mirror of ESO’s Extremely Large Telescope (ELT). The PACTs will support each segment and actively control its position in three directions, known as piston, tip and tilt.