The Cerro Tololo Inter-American Observatory (CTIO) is an astronomical observatory located on Cerro Tololo in the Atacama Desert of northern Chile, with additional facilities located on Cerro Pachón about 10 kilometres (6.2 mi) to the southeast. It is within the Coquimbo Region and approximately 80 kilometres (50 mi) east of La Serena, where support facilities are located.
The site was identified by a team of scientists from Chile and the United States in 1959, and it was selected in 1962.Construction began in 1963 and regular astronomical observations commenced in 1965.Construction of large buildings on Cerro Tololo ended with the completion of the Victor M. Blanco Telescope in 1974, but smaller facilities have been built since then. Cerro Pachón is still under development, with two large telescopes inaugurated since 2000, and one in the early stages of construction.
The principal telescopes at CTIO are the 4 m Victor M. Blanco Telescope, named after Puerto Rican astronomer Victor Manuel Blanco, and the 4.1 m Southern Astrophysical Research (SOAR) telescope, which is situated on Cerro Pachón.Other telescopes on Cerro Tololo include the 1.5 m, 1.3 m, 1.0 m, and 0.9 m telescopes operated by the SMARTS consortium. CTIO also hosts other research projects, such as PROMPT, WHAM, and LCOGTN, providing a platform for access to the southern hemisphere for U.S. and World-wide scientific research.
CTIO is one of two observatories managed by the National Optical Astronomy Observatory (NOAO), the other being Kitt Peak National Observatory (KPNO) near Tucson, Arizona. NOAO is operated by the Association of Universities for Research in Astronomy (AURA), which owns the property around the two peaks in Chile and at the headquarters in La Serena. AURA also operates the Space Telescope Science Institute and the Gemini Observatory. The 8.1 m (320 in) Gemini South Telescope located on Cerro Pachón is managed by AURA separately from CTIO for an international consortium.The National Science Foundation (NSF) is the funding agency for NOAO.
The Small and Medium Research Telescope System (SMARTS) is a consortium formed in 2001 after NOAO announced it would no longer support anything smaller than two meters at CTIO. The member institutions of SMARTS now fund and manage observing time on four telescopes that fit that definition. Access has also been purchased by individual scientists.SMARTS contracts with NOAO to maintain the telescopes it controls at CTIO, and NOAO retains the right to 25% of the observing time, and Chilean scientists retain 10%. SMARTS began managing telescopes in 2003.
SOAR Telescope -4.1 m reflector
Blanco Telescope -4.0 m reflector
SMARTS 1.5-meter -1.5 m reflector
SMARTS 1.3-meter -1.3 m reflector
SMARTS "Yale" Telescope -1.0 m reflector
LCOGTN (u/c) -3× 1.0 m reflectors
SMARTS 0.9-meter -0.9 m reflector
PROMPT 7 (u/c) -0.8 m reflector
Curtis-Schmidt Telescope -0.6 m reflector
Wisconsin H-Alpha Mapper -0.6 m telescope
SARA South Telescope -0.6 m reflector
CHASE Telescope -0.5 m reflector
PROMPT -6× 0.4 m reflectors
GONG -Solar Telescope