The wide field phasing testbed for the Giant Magellan Telescope

Abstract

The Wide Field Phasing Testbed will be used to test phasing and active optics systems planned for the doubly segmented Giant Magellan Telescope. The testbed consists of a set of optical relays in which are located segmented and deformable mirrors that represent the GMT M1 and M2 mirrors. The testbed output beam has the GMT's f/8.16 focal ratio and has a back focal distance large enough to allow using a full-scale prototype of one unit of the Acquisition Guiding and Wavefront Sensing System. The testbed will reproduce the telescope field dependent aberrations that result from misalignment of M1 and M2. Over its 20mm diameter field of view, the testbed will generate aberrations corresponding to the 20′ field of the GMT. A rotating turbulence screen and zero-deviation prisms in the testbed will generate seeing limited images that correspond to typical atmospheric seeing and dispersion conditions expected at the GMT. The software for the testbed is designed to allow connection of the testbed wavefront sensing analysis components to simulations of the testbed optical system, as well as to conform to the planned software interfaces of the GMT's telescope control system. © 2022 SPIE.