Two Micron All-Sky Survey

Observation Survey

Astronomical survey of the whole sky in the infrared

The Two Micron All-Sky Survey, or 2MASS, was an astronomical survey of the whole sky in infrared light. It took place between 1997 and 2001, in two different locations: at the U.S. Fred Lawrence Whipple Observatory on Mount Hopkins, Arizona, and at the Cerro Tololo Inter-American Observatory in Chile, each using a 1.3-meter telescope for the Northern and Southern Hemisphere, respectively. It was conducted in the short-wavelength infrared at three distinct frequency bands near 2 micrometres, from which the photometric survey with its HgCdTe detectors derives its name.

Read on Wikipedia License Image-Source