2MASS
Observations for the Two Micron All-Sky Survey (2MASS) began in 1997 and were completed in 2001 at two telescopes located one each in the northern and southern hemispheres (Mt. Hopkins, Arizona and Cerro Tololo/CTIO, Chile, respectively) to ensure coverage of the entire sky. The most ambitious project to map the night sky to date, the final (post-processing) data release for 2MASS occurred in 2003. The whole sky was covered using a photometric system of three infrared wavebands around 2 micrometres (m): J (1.25 m), H (1.65 m), and Ks (2.17 m).
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