Veloce environmental control system

Gaston Gausachs*, Robert Boz, Tom Carkic, Michael Ellis, James Gilbert, Nicholas Herrald, Michael Ireland, Ellie O'brien, Ian Price, Matthew Robertson, Colin Vest

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Citation (Scopus)


Veloce is an ultra-stabilized Echelle spectrograph for precision radial velocity measurements of stars. In order to maximize the grating performance, the air temperature as well as the air pressure surrounding it must be maintained within tight tolerances. The control goal was set at +/-10 mK and +/-1 mbar for air temperature and pressure respectively. The strategy developed by the design team resulted in separate approaches for each of the two requirements. A constrained budget early in the concept phase quickly ruled out building a large vacuum vessel to achieve stable air pressure. Instead, a simplified approach making use of a slightly over pressurized enclosure containing the whole spectrograph was selected in conjunction with a commercially available pressure controller. The temperature stability of Veloce is maintained through a custom array of PID controlled heaters placed on the outer skin of the internal spectrograph enclosure. This enclosure is also fully lined with 19 mm thick insulating panels to minimize the thermal fluctuations. A second insulated enclosure, built around the internal one, adds a layer of conditioned air to further shield Veloce from the ambient thermal changes. Early success of the environment control system has already been demonstrated in the integration laboratory, achieving results that amply exceed the goals set forth. Results presented show the long term stability of operation under varying barometric conditions. This paper details the various challenges encountered during the implementation of the stated designs, with an emphasis on the control strategy and the mechanical constraints to implement the solutions.

Original languageEnglish
Title of host publicationGround-based and Airborne Instrumentation for Astronomy VII
EditorsLuc Simard, Luc Simard, Christopher J. Evans, Hideki Takami
ISBN (Print)9781510619579
Publication statusPublished - 2018
EventGround-based and Airborne Instrumentation for Astronomy VII 2018 - Austin, United States
Duration: 10 Jun 201814 Jun 2018

Publication series

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


ConferenceGround-based and Airborne Instrumentation for Astronomy VII 2018
Country/TerritoryUnited States


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