Camera articulation prototype of the Giant Magellan Telescope Multi-object Astronomical and Cosmological Spectrograph (GMACS)

Tae Geun Ji, Erika Cook, Soojong Pak, Evan Kelly, Leonardo Bush, Leonardo Barba, Jeffrey Mason, Hye In Lee, Darren L. Depoy, Jennifer L. Marshall, Nat Butler, Daniel M. Faes, Cynthia Froning, Johnathan Gamaunt, Damien Jones, Philip Mauskopf, Claudia Mendes De Oliveira, Casey Papovich, Travis Prochaska, Rafael A.S. RibeiroLuke M. Schmidt, Paul Scowen, Aline Souza, Keith Taylor, Antonio Braulio Neto, Priscila Pires

Research output: Chapter in Book/Report/Conference proceedingConference contribution


We describe the camera articulation prototype (CAP) for the Giant Magellan Telescope Multi-object Astronomical and Cosmological Spectrograph (GMACS), which is a wide field, multi-object, moderate-resolution, optical spectrograph of the Giant Magellan Telescope (GMT). The GMACS will have the Camera and Grating Articulation System (CGAS) which has two independent cameras and grating modules. The grating angles and the camera angles can be changed to adjust the dispersed light bands on the detector. The electronics components of this system include motors with encoder, pneumatic brakes, and limit switches. We demonstrate how to control the camera angles using a prototype that is designed for the camera articulation controller as a miniature model of the GMACS. The prototype was built with commercially-available extruded aluminum struts and 3D-printed parts and includes two motors with encoders. The prototype was produced quickly and inexpensively, but replicates all functions of the camera articulation mechanism in GMACS. We have developed the control package for the prototype that will be one of the GMACS Device Control System (DCS). The software is designed by the Agile development process and SysML, and developed using Visual C++ on Windows OS. This software has five major control functions: power, homing, resolution mode changing, limit detection, and emergency process. The limit detection is implemented by setting up the limit angle range in the software, because the limit switches are not included in the prototype. We present the demonstration result and discuss the details of the communication route about data flow between high-end user software and hardware components.

Original languageEnglish (US)
Title of host publicationSoftware and Cyberinfrastructure for Astronomy VI
EditorsJuan C. Guzman, Jorge Ibsen
ISBN (Electronic)9781510636910
StatePublished - 2020
EventSoftware and Cyberinfrastructure for Astronomy VI 2020 - Virtual, Online, United States
Duration: Dec 14 2020Dec 18 2020

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceSoftware and Cyberinfrastructure for Astronomy VI 2020
Country/TerritoryUnited States
CityVirtual, Online


  • Giant Magellan Telescope
  • camera articulation
  • multi-object spectrograph
  • software development

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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