Cerro Tololo Inter-American Observatory
We are currently not hosting visitors to our summit or base facilities until at least the end of August 2021.
From the first observations in 1965, Cerro Tololo, located in Chile, has served as the principal platform for U.S. astronomical investigation of the southern skies.
Cerro Tololo Inter-American Observatory (CTIO), a program of the NOIRLab, is a complex of astronomical telescopes and instruments located approximately 500 km (310 miles) north of Santiago, and 80 km (50 miles) to the east of La Serena, Chile, at an altitude of 2200 meters (7200 feet).
CTIO operates the 4.0-meter Blanco telescope on Cerro Tololo which features the Dark Energy Camera (DECam), a high-performance, wide-field CCD imager built to carry out the Dark Energy Survey (DES) (a US Department of Energy Office of Science-led project). It also operates the 4.1-meter Southern Astrophysical Research (SOAR) Telescope on the adjacent Cerro Pachón (a partnership between Ministério da Ciência, Tecnologia, Inovações e Comunicações Brazil, NOIRLab, the University of North Carolina at Chapel Hill and Michigan State University). The Cerro Tololo 1.5-meter and 0.9-meter telescopes are being operated by the SMARTS Consortium with support from CTIO. Cerro Tololo also hosts 11 tenant observatories and research projects, operating more than 20 telescopes, providing a platform for access to the southern hemisphere for US and worldwide scientific research.
Daytime guided tours of the facilities on Cerro Tololo are available on Saturdays all year round.
We are privileged to conduct research on Cerro Tololo and Cerro Pachón in Chile, and acknowledge the Indigenous communities in Chile as original stewards of these lands.
CTIO is operated by the NSF’s NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA).