The Mid-resolution InfRAreD Astronomical Spectrograph (MIRADAS) is a near-infrared (NIR) multi-object spectrograph for the Gran Telescopio Canarias (GTC). It can simultaneously observe multiple targets selected by 20 identical deployable probe arms with pickoff mirror optics. The bases of the arms are fixed to the multiplexing system (MXS) plate, a circular platform, and arranged in a circular layout with minimum separation between elements of the arms. This document presents the MXS prototype P2a, a full-scale, fully operational prototype of a MIRADAS probe arm. This planar closed-loop mechanism compared to other previous designs offers some advantages specially in terms of stability and from the point of view of optics. Unfortunately, these benefits come at the expense of a more complicated kinematics and an unintuitive arm motion. Furthermore, the cryogenic motor controllers used in prototyping impose severe restrictions in path planing. They negatively impact in the slice of pie approach, a collision-avoidance patrolling strategy that can gives good results in other scenarios. This study is a starting point to define collision-free trajectory algorithms for the 20 probe arms of MIRADAS.

Date Published: 18 July 2014
PDF: 13 pages
Proc. SPIE 9151, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation, 91515S (18 July 2014); doi: 10.1117/12.2055466

Published in SPIE Proceedings Vol. 9151:
Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation
Ramón Navarro; Colin R. Cunningham; Allison A. Barto, Editor(s)