ELT site testing — Cerro Tolonchar / Chile

The Extremely Large Telescope (ELT) programme office has studied half a dozen potential sites for the future ELT observatory, which, with its 40-metre-class diameter, will be the world’s biggest eye on the sky. Various aspects need to be considered in the site selection process. Parameters taken into account are not restricted to ‘sky quality’, but include more general scientific aspects, as well as parameters essential for construction and operations (e.g. accessibility, water and power supply, political stability etc.).

The above picture shows a night time view toward east from the summit of Cerro Tolonchar, a site located in Chile. It is on the ELT Site Selection Advisory Committee's final short list for the recommended site.