Two Micron All Sky Survey (2MASS)

One 1.3 meter telescope is located in Mt. Hopkins, AZ (top) and the other 1.4 meter telescope is in Cerro Tololo Inter-American Observatory, Chile (bottom).

Mission duration
Operations began in June 1997 (northern facility) and March 1998 (southern facility) and both ended February 15, 2001.
Light observed
2MASS's homepage