New prime focus rotator system for the WHT

Ander San Vicente; Gaizka Murga; Iñigo Uriarte; David Fernández; Rafael Urrutia; Amaya Mugica; Ramón Campo; Javier Ariño; Lander de Bilbao; Anna Kosmalska; Gavin Dalton; Kevin Middleton; Scott Trager; J. Alfonso L. Aguerri; José Miguel Delgado Hernandez; José Alonso Burgal; José Miguel Herreros; Piercarlo Bonifacio; Antonella Vallenari; Esperanza Carrasco; Don Carlos Abrams; Kevin Dee; Emilie Lhoméh; Frank Gribbin; Jure Skvarc; Carlos Martin

doi:10.1117/12.2562638

13 December 2020 New prime focus rotator system for the WHT

Ander San Vicente , Gaizka Murga , Iñigo Uriarte, David Fernández, Rafael Urrutia, Amaya Mugica, Ramón Campo, Javier Ariño, Lander de Bilbao, Anna Kosmalska, Gavin Dalton, Kevin Middleton, Scott Trager, J. Alfonso L. Aguerri, José Miguel Delgado Hernandez, José Alonso Burgal, José Miguel Herreros, Piercarlo Bonifacio, Antonella Vallenari, Esperanza Carrasco, Don Carlos Abrams, Kevin Dee, Emilie Lhoméh, Frank Gribbin, Jure Skvarc, Carlos Martin

Author Affiliations +

Proceedings Volume 11445, Ground-based and Airborne Telescopes VIII; 114454S (2020) https://doi.org/10.1117/12.2562638
Event: SPIE Astronomical Telescopes + Instrumentation, 2020, Online Only

Conference Poster

Abstract

WEAVE is a new wide-field multi-object spectroscopy (MOS) facility proposed for the prime focus of the 4.2m William Herschel Telescope. The facility comprises a new 2-degree field-of-view Prime Focus Corrector (PFC) with a 1000-multiplex fibre positioner, a small number of individually deployable integral field units, and a large single integral field unit (IFU). The IFUs and the MOS fibres can be used to feed a dual-beam spectrograph that will provide full coverage of the majority of the visible spectrum in a single exposure at a spectral resolution of ~5000 or modest wavelength coverage in both arms at a resolution ~20000. In order to compensate the field rotation, the Prime Focus Rotator (PFR) is assembled in between the WEAVE Fiber Positioner (system that positions the fibers in the focal plane) and with the Central Can (contains the Prime Focus corrector optics) on the William Herschel Telescope (WHT). The Prime Focus Rotator must provide a rotation degree of freedom for the Fibre Positioner with a high bending stiffness (causing a deflection smaller than 0.008° between interface flanges) adding the minimum mass possible to the system (less than 700kg). This is easily identified as the main design driver to be considered. The Prime Focus Rotator positions the Fibre Positioner to an accuracy of 5 arcsec when tracking and guides all the fibres and other power and control lines through a cable wrap, for which the available space is limited. IDOM proposal to comply with these coupled requirements consists of an optimized structural system with a slightly preloaded cross roller bearing providing the highest possible stiffness to weight ratio. The rotation is driven by means of a direct drive motor powered by a servo drive. For the Cable Wrap, a compact design based on a concept previously developed by IDOM for the Folded Cassegrain Sets the GTC was proposed.

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Ander San Vicente , Gaizka Murga , Iñigo Uriarte, David Fernández, Rafael Urrutia, Amaya Mugica, Ramón Campo, Javier Ariño, Lander de Bilbao, Anna Kosmalska, Gavin Dalton, Kevin Middleton, Scott Trager, J. Alfonso L. Aguerri, José Miguel Delgado Hernandez, José Alonso Burgal, José Miguel Herreros, Piercarlo Bonifacio, Antonella Vallenari, Esperanza Carrasco, Don Carlos Abrams, Kevin Dee, Emilie Lhoméh, Frank Gribbin, Jure Skvarc, and Carlos Martin "New prime focus rotator system for the WHT", Proc. SPIE 11445, Ground-based and Airborne Telescopes VIII, 114454S (13 December 2020); https://doi.org/10.1117/12.2562638

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