Design of Pocket-GMT: an optical emulation of the Giant Magellan Telescope

The concept design for a laboratory based telescope emulator for the Giant Magellan Telescope (GMT) is described here. The Giant Magellan Telescope has a primary mirror comprised of 7 segments, and a secondary mirror with matching segmentation. The phasing of the GMT is a complex problem; a phasing testbed, Pocket-GMT, has been designed by a group within the Research School of Astronomy and Astrophysics at the Australian National University for the Giant Magellan Telescope Corporation. Pocket-GMT uses a novel technique to split the bending modes between a piston/tip-tilt surface and a deformable mirror. Pocket-GMT will demonstrate successful phasing of an optical miniature GMT by the planned prototype wavefront sensing systems. By reproducing the optical characteristics of the GMT on a small scale, Pocket-GMT will reduce the risk associated with the phasing system and provide a platform to test the telescopeFLs instrumentation prior to commissioning.