A 4.1-m reflector jointly owned by the US National Optical Astronomy Observatory (NOAO), Brazil, Michigan State University, and the University of North Carolina at Chapel Hill. It is sited at an altitude of 2700 m on Cerro Pachón mountain in Chile and is operated by the Cerro Tololo Inter-American Observatory. It opened in 2004.

http://www.soartelescope.org/ Official telescope website.