Design and manufacture of athermalized optomechanical mounts for GRANCAIN, the infrared imaging instrument for GTC's adaptive optics

Eduardo D. González-Carretero; Verónica Canto-Caño; José M. Delgado-Hernández; Antonio F. Moreno-Martín; Roberto Simoes; Marcos Reyes García-Talavera; José A. Acosta-Pulido; Víctor J. S. Béjar; Fabio Tenegi-Sanginés; Afrodisio Vega-Moreno; Ángel Mato; Roberto López-López; Jesús Patrón-Recio; Heidy Moreno-Arce

doi:10.1117/12.3016627

26 August 2024 Design and manufacture of athermalized optomechanical mounts for GRANCAIN, the infrared imaging instrument for GTC's adaptive optics

Eduardo D. González-Carretero, Verónica Canto-Caño, José M. Delgado-Hernández, Antonio F. Moreno-Martín, Roberto Simoes, Marcos Reyes García-Talavera, José A. Acosta-Pulido, Víctor J. S. Béjar, Fabio Tenegi-Sanginés, Afrodisio Vega-Moreno, Ángel Mato, Roberto López-López, Jesús Patrón-Recio, Heidy Moreno-Arce

Author Affiliations +

Proceedings Volume 13100, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation VI; 131006V (2024) https://doi.org/10.1117/12.3016627
Event: SPIE Astronomical Telescopes + Instrumentation, 2024, Yokohama, Japan

Conference Poster

Abstract

GRANCAIN (GRAN CAmara INfrarroja) is a first-light imaging instrument in the infrared J, H and K bands that will be integrated into the adaptive optics focus of the Gran Telescopio de Canarias. The purpose of the instrument is to capture SWIR diffraction-limited images for a field of view of 22x22 arcsec. The instrument boasts a telecentric optical design with a collimator-camera configuration featuring a 2:1 magnification ratio. Housed within a 160-liter aluminum cryostat, its optical path includes a cold stop, a filter wheel, and a 4Mpx Hawaii-2 PACE Teledyne detector, meticulously engineered for operation at 77K. The optics is held in place by black anodized 6061-T6 aluminum supports. These mounts serve the critical purpose of precisely positioning the optics along the Z optical axis. The opto-mechanical frames contain adjustment elements in five degrees of freedom (all except the clock) for optical alignment and to compensate the thermal differential contractions that occur during the cooling-down process. Additionally, the lens-housing cell combines different geometries and materials with different coefficients of thermal expansion to avoid stresses on the glass so as not vary its relative position. A symmetrical and athermalized opto-mechanical design, free of residual stresses, helps to minimize the deviations of the optical axis and thus facilitates the iterative process of optical alignment in cryogenic conditions. A strict manufacturing and metrological control process were necessary in order to achieve the objectives for optimum image quality. The article contains a detailed description of the design, fabrication techniques, metrology, integration, alignment, and testing of the athermalized opto-mechanical elements.

(2024) Published by SPIE. Downloading of the abstract is permitted for personal use only.

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Eduardo D. González-Carretero, Verónica Canto-Caño, José M. Delgado-Hernández, Antonio F. Moreno-Martín, Roberto Simoes, Marcos Reyes García-Talavera, José A. Acosta-Pulido, Víctor J. S. Béjar, Fabio Tenegi-Sanginés, Afrodisio Vega-Moreno, Ángel Mato, Roberto López-López, Jesús Patrón-Recio, and Heidy Moreno-Arce "Design and manufacture of athermalized optomechanical mounts for GRANCAIN, the infrared imaging instrument for GTC's adaptive optics", Proc. SPIE 13100, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation VI, 131006V (26 August 2024); https://doi.org/10.1117/12.3016627

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