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Characteristics of the 2MASS Prototype Survey

The 2 Micron All Sky Survey (2MASS) will catalog over 100,000,000 individual objects, the vast majority of which will be stars of spectral type K and later. For many projects it will be important to develop techniques to identify interesting objects within this data set. The combination of near‐IR and visible light observations will be a powerful tool for finding objects from brown dwarfs to dust‐enshrouded quasars. This paper describes prototype hardware and software systems used as part of the preparation for the 2MASS survey. Three years of observations with prototype systems have produced a database of more than 1 million objects. A companion paper describes the comparison of these data with optical plate material and visible spectroscopic observations resulting in the discovery of a quasar with a redshift of 0.147.