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Proceedings Paper

Giant Magellan Telescope site testing: PWV statistics and calibration
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Paper Abstract

Cerro Las Campanas located at Las Campanas Observatory (LCO) in Chile has been selected as the site for the Giant Magellan Telescope. We report results obtained since the commencement, in 2005, of a systematic site testing survey of potential GMT sites at LCO. Atmospheric precipitable water vapor (PWV) adversely impacts mid-IR astronomy through reduced transparency and increased background. Prior to the GMT site testing effort, little was known regarding the PWV characteristics at LCO and therefore, a multi-pronged approach was used to ensure the determination of the fraction of the time suitable for mid-IR observations. High time resolution monitoring was achieved with an Infrared Radiometer for Millimeter Astronomy (IRMA) from the University of Lethbridge deployed at LCO since September of 2007. Absolute calibrations via the robust Brault method (described in Thomas-Osip et al.1) are provided by the Magellan Inamori Kyocera Echelle (MIKE), mounted on the Clay 6.5-m telescope on a timescale of several per month. We find that conditions suitable for mid-IR astronomy (PWV < 1.5 mm) are concentrated in the southern winter and spring months. Nearly 40% of clear time during these seasons have PWV < 1.5mm. Approximately 10% of these nights meet our PWV requirement for the entire night.

Paper Details

Date Published: 6 August 2010
PDF: 10 pages
Proc. SPIE 7733, Ground-based and Airborne Telescopes III, 77334N (6 August 2010); doi: 10.1117/12.857982
Show Author Affiliations
Joanna E. Thomas-Osip, GMTO Corp. (United States)
Las Campanas Observatory (Chile)
Gabriel Prieto, GMTO Corp. (United States)
Las Campanas Observatory (Chile)
Andrew McWilliam, Carnegie Observatories (United States)
Mark M. Phillips, Las Campanas Observatory (Chile)
Carnegie Observatories (United States)
Patrick McCarthy, GMTO Corp. (United States)
Carnegie Observatories (United States)
Matt Johns, GMTO Corp. (United States)
Richard Querel, Univ. of Lethbridge (Canada)
David Naylor, Univ. of Lethbridge (Canada)

Published in SPIE Proceedings Vol. 7733:
Ground-based and Airborne Telescopes III
Larry M. Stepp; Roberto Gilmozzi; Helen J. Hall, Editor(s)

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