Research Byte

Published in the RSAA Lunations
Vol1 Issue14 1–31 March 2021

Ground Layer Adaptive Optics for the Subaru telescope

ULTIMATE-Subaru is the next generation facility instrument project at the Subaru Telescope, an 8-meter optical-infrared telescope at the summit of Maunakea, Hawaii. ULTIMATE-Subaru comprises a wide-field near-infrared (1.0-2.5μm) imager and a multi-object spectrograph that will benefit from a Ground Layer Adaptive Optics (GLAO) to improve the seeing by a factor of 2 over a wide field of view (up to ~20 arcmin in diameter).

The GLAO system is a major instrumentation project, led by the Subaru Telescope in collaboration with world-leading astronomers, adaptive optics and laser scientists and engineers from institutions in Australia (ANU), Japan (Tohoku University) and Taiwan (Academia Sinica Institute of Astronomy and  Astrophysics, ASIAA). The RSAA participation in GLAO includes the Laser Guide Star Facility and the Wavefront Adapter Flange, two key elements for the success of this Ground Layer Adaptive Optics system.

The GLAO Laser Guide Star Facility includes two sodium guidestar lasers to be split in a total of four, generating an asterism of four artificial stars on the Hawaiian skies. Each of these laser guide stars (LGS) will be used as a reference to measure the atmospheric turbulence by four LGS wavefront sensors working together with four Natural Guide Star wavefront sensor. The Wavefront Adaptor Flange, the subsystem containing the wavefront sensor instances, is being designed to interface with both Nasmyth and Cassegrain foci of the Subaru Telescope, providing Adaptive Optics capability to the two instruments, the wide-field imager and the multi-object spectrograph.

The AITC team is working on the second phase of the GLAO project that will end by the Preliminary Design Review, after which the detailed design phase will commence. Exciting cutting-edge developments are about to happen! Stay tuned!

 

By: Dr Noelia Martinez

_{Pic credit: Yosuke Minowa, Yusei Koyama, Yoshito Ono, Ichi Tanaka, Takashi Hattori, Christophe Clergeon, Masayuki Akiyama, Tadayuki Kodama, Kentaro Motohara, François Rigaut, Céline d'Orgeville, Shiang-Yu Wang, Michitoshi Yoshida, "ULTIMATE-Subaru: enhancing the Subaru's wide-field capability with GLAO," Proc. SPIE 11203, Advances in Optical Astronomical Instrumentation 2019, 112030G (3 January 2020); https://doi.org/10.1117/12.2560539}