Giant Magellan Telescope primary mirror cells

The Giant Magellan Telescope (GMT) Mirror cells provide positioning, support, with active optics compensation, and thermal control of the seven 8.4 meter primary mirror segments. Each mirror cell is a large steel welded structure, and in the case of the outer off axis segments, is designed to be interchangeable for any one of the 6 possible mirror positions. The mirror support and active optics compensation are provided through a series of single axis and three axis pneumatic actuators that control the force used to support the mirror at a total of 165 positions and allows for support of the mirror in any one of the six positions. Mirror positioning is provided by a stiff hexapod actuator system between the mirror and the mirror cell. Mirror thermal control is provided by a series of fans that pressurize the mirror cell and condition the air before it is directed into the mirror through 1700 nozzles.