Site Selection

Cerro Pachón, a mountain peak in northern Chilé, has been selected as the site for the Large Synoptic Survey Telescope.

LSST site selection was identified early in the project development as a critical task. A site selection process was set up in Fall 2003 to begin investigating the possible locations of the observatory. LSST will need to be located on one of the best world sites in order to achieve its survey goals. For a variety of reasons including costs and schedule, only existing sites located in the Americas or Europe were deemed suitable for the LSST project. Candidate sites included Southwestern US, Baja California Mexico, the Canaries, Hawaii, and Chilé. A major effort was then started by the LSST project to gather information on the existing sites from local measurements published or provided by existing observatories and studies funded by other telescope site selection groups.

A site selection committee was formed with recognized, independent experts to give a final recommendation. Recognizing that a full-scale investigation of all candidate sites was unfeasible, the committee was asked in a first step to down-select to 4 sites using information accumulated by the LSST project. The 4 selected sites were Cerro Pachón (Chilé), Las Campanas (Chilé), San Pedro Mártir (Mexico), and La Palma (Spain). At the second Selection Meeting in January 2005, the Selection Commitee recommended to keep San Pedro Mártir, Cerro Pachón and Las Campanas.

At the same time, the committee identified areas where complementary information will need to be provided for the final down-selection to 2 sites, and the project started immediate investigation. After down-selection to two sites, LSST invested in geotechnical and environmental studies to deliver a detailed estimate of the construction cost. The final decision, Cerro Pachón, was based on the results of these complementary studies.

Site Selection Committee

Mark Sarazin, Chair, European Southern Observatory 
William Althouse, LSSTC, SLAC National Accelerator Laboratory 
Roc Cutri, California Institute of Technology, IPAC 
Bob Gehrz, University of Minnesota 
Alan Harris, Space Science Institute 
Frank Hill, National Solar Observatory 
Zeljko Ivezic, University of Washington 
Steve Kahn, SLAC National Accelerator Laboratory 
Rene Racine, University de Montreal 
Simon Radford, National Radio Astronomy Observatory 
Michael Strauss, Princeton University

Don Sweeney, LSSTC (non-voting)
Tony Tyson, UC Davis (non-voting)

NSF Representative (observer)
DOE Representative (observer)