Thirty Meter Telescope Site Testing I: Overview

TL;DR

This paper reviews five candidate sites for the Thirty Meter Telescope, detailing five years of atmospheric measurements and analysis, ultimately narrowing down to two promising locations without a clear superior.

Contribution

First comprehensive overview of TMT site testing process, including site selection criteria, atmospheric measurements, and comparative analysis of candidate sites.

Findings

All five sites are suitable for an extremely large telescope.

No single site clearly outperforms the others based on combined properties.

Two sites, Armazones and Mauna Kea 13N, are identified as the most promising for further consideration.

Abstract

As part of the conceptual and preliminary design processes of the Thirty Meter Telescope (TMT), the TMT site testing team has spent the last five years measuring the atmospheric properties of five candidate mountains in North and South America with an unprecedented array of instrumentation. The site testing period was preceded by several years of analyses selecting the five candidates, Cerros Tolar, Armazones and Tolonchar in northern Chile; San Pedro Martir in Baja California, Mexico and the 13 North (13N) site on Mauna Kea, Hawaii. Site testing was concluded by the selection of two remaining sites for further consideration, Armazones and Mauna Kea 13N. It showed that all five candidates are excellent sites for an extremely large astronomical observatory and that none of the sites stands out as the obvious and only logical choice based on its combined properties. This is the first article in a series discussing the TMT site testing project.