An observatory at an altitude of 2215 m on Cerro Tololo mountain, Chile, 55 km southeast of La Serena, where its headquarters are. Founded in 1963, it is part of the US National Optical Astronomy Observatory. Cerro Tololo’s main instrument is the 4-m Blanco Telescope, opened in 1974, named after the observatory’s first director, the American astronomer Victor Manuel Blanco (1918–2011). This telescope is the southern twin of the 4-m instrument at Kitt Peak National Observatory. Other instruments include a 1.5-m reflector, opened in 1968; a 1.3-m reflector originally used for the Two-Micron All-Sky Survey, opened in 1997 but transferred to CTIO ownership in 2001; a 0.9-m reflector, opened in 1967; Yale University’s 1-m reflector, installed here in 1973; the University of Michigan’s 0.6-m Curtis Schmidt, originally opened in 1950 but moved here in 1967; a 0.6-m reflector operated since 2010 by the Southeastern Association for Research in Astronomy (SARA); the 0.6-m Wisconsin H-Alpha Mapper (WHAM) telescope, originally opened on Kitt Peak in 1996 but moved to CTIO in 2009; and eight 0.4-m telescopes of the MEarth-South project to look for Earthlike planets around M dwarfs, opened in 2014. The 1.5-m, 1.3-m, 1-m, and 0.9-m have been operated since 2003 by the Small and Moderate Aperture Research Telescope System (SMARTS) consortium of US institutions. The Curtis Schmidt is now used for monitoring orbital debris and is known as the Michigan Orbital Debris Survey Telescope (MODEST). In 2006 the University of North Carolina at Chapel Hill began operation of the PROMPT array (Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes) consisting of six 0.4-m telescopes to study gamma-ray bursts. CTIO also operates the 4.1-m Southern Astrophysical Research (SOAR) Telescope on Cerro Pachón, a peak 10 km to the southeast of Cerro Tololo.

http://www.ctio.noao.edu/ Official observatory website.