Optomechanical design of the Laser Launch Telescope for the GTC adaptive optics system

Abstract

LIDAX is developing the Laser Launch Telescope for the Gran Telescopio de Canarias (GTC) located at the Roque de los Muchachos Observatory on the island of La Palma, Canary Islands, Spain. This unique beam expander will be part of the GTC Adaptive Optics System (GTCAO) facility, managed by the IAC (Instituto de Astrofísica de Canarias), and will allow the creation of laser guide stars to feed the Adaptive Optics System of the GTC, removing the atmospheric turbulence to obtain high quality images of the stellar objects observed. This paper describes the opto-mechanical design and shows how the design- analysis process is performed to meet the performance requirements, explaining the STOP analysis carried out together with INTA-LINES. Such a process includes the initial mechanical design, the elaboration of both thermal and FEM models to analyze the behavior in terms of temperatures distribution, stiffness, and thermo-elastic effects, and of course the of lenses’ displacements and deformations under the different load cases and boundary conditions, which are transformed into Zernike Polynomials to evaluate the WFE of the Telescope, which allows to obtain, closing the loop, the best optical performance.