The Adaptive Optics system of the 10-m class Gran Telescopio Canarias (GTCAO) is completing the acceptance tests in the laboratory at the Instituto de Astrofísica de Canarias, to be ready for its integration in the telescope at Roque de Los Muchachos Observatory (ORM) in 2023. The AO system has been designed with robustness and operability as its key characteristics, and will be a facility of GTC. It features a single deformable mirror (DM) with 373 actuators, conjugated to the telescope pupil, and a Shack-Hartmann wavefront sensor (WFS) with 312 subapertures, using an OCAM2 camera. The expected performance of the GTCAO system working on average atmospheric conditions and bright NGS is 65% Strehl Ratio in K-band. In this paper we present the characterization of the system and the tests that have been performed for its acceptance at the laboratory. A series of calibrations are required and methodically run to achieve its ultimate performance: flatten the DM, acquire the Interaction Matrix and the reference slopes, correct the non-common path aberrations etc. The WFS requires additional calibrations, to compensate the pupil displacement in all the 2 arcminutes patrol field of view, and to correct the atmospheric dispersion in the visible. Close loop gains and sampling frequency are adapted to the changing conditions, and lookup tables are created for that purpose. The compliance with the system specifications has been verified. After verification of the final software functionalities for telescope operation, the system will be shipped to the ORM, to be installed and aligned on the Nasmyth platform of the GTC, and to be integrated with the telescope control system.
The Laser Guide Star Facility (LGSF) of GTC will generate a laser guide star (LGS) in the high atmosphere for the GTC Adaptive Optics System (GTCAO) to measure and correct the effect of the atmospheric turbulence. The GTCAO LGS Wavefront Sensor (LWS) will be based on a Shack Hartmann WFS and placed on the GTCAO optical bench, where the Natural Guide Star (NGS) Wavefront Sensor is already installed. The science dichroic splits the light beam so that the visible range (0.47-0.9μm) is reflected to the NGS WFS, and the infrared range 0.9-2.5μm is transmitted to the science instrument. A new second dichroic (LWS DC) will be installed in the visible path, to reflect 589nm (FWHM 12nm) towards the LWS, and to transmit the rest of the visible light to the NGS WFS. In addition, the system will count on an LGS calibration source. The proceeding describes the opto-mechanical design of the LWS System, covering its different subsystems: LWS Dichroic, LWS Sensor and LWS Calibration Unit.
The Laser Guide Star Facility (LGSF) of Gran Telescopio Canarias (GTC) will be in charge of generating a Laser Guide Star (LGS) in the high atmosphere for the GTC Adaptive Optics System (GTCAO) to measure and correct the effect of the atmospheric turbulence. This proceeding analyses the thermal response of the LGS launch systems in operation under the direct action of the laser, and its interaction with respect GTC Telescope environment.
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