What is 2MASS?

Humans have historically placed themselves and the world around them in context by surveying their environment.

The Two Micron All Sky Survey, or 2MASS, is a joint project of the University of Massachusetts in Amherst (UMass) and the Infrared Processing and Analysis Center (IPAC) at the California Institute of Technology (Caltech). 2MASS has uniformly scanned the entire sky in three near-infrared bands, using two highly-automated 1.3-meter telescopes, one at a northern hemisphere facility and the other in a southern hemisphere facility. Pictured at left is the northern telescope facility at sunset. In addition to helping to understand and interpret astronomical observations made using other telescopes at other observatories, 2MASS will provide direct answers to immediate questions on the overall structure of our Milky Way Galaxy and the Universe around us. Already, 2MASS is mapping many new objects unknown before now, including rare, new objects, such as cool brown dwarfs and red quasars, and stars, star clusters, and galaxies previously hidden behind the obscuring dust of our Milky Way. 2MASS will lay much of the ground work for the best use by astronomers of the next generation of infrared space missions and current and future powerful ground-based facilities.

2MASS began operations in the northern hemisphere in 1997 June, and in the southern hemisphere in 1998 March. Survey operations were completed in both hemispheres on 2001 February 15. UMass constructed the telescope facilities and was responsible for maintaining them, as well as for the scheduling and conducting of the telescope observations. The observations subsequently have been processed by IPAC, which is also responsible for assembling and distributing the 2MASS data products. These products are an enormous number of images and huge catalogs of stars and galaxies compiled from the images. The catalogs and images are distributed freely to the astronomical community and the general public, primarily through the Internet, via the World Wide Web. About 24.5 terabytes (that's 24,500 gigabytes, or 24.5 million megabytes!) of raw computer data have been synthesized into a final 12 terabytes of catalogs and images (currently, about 2 terabytes are available online in a compressed format). 2MASS represents part of astronomy's future, as scientists learn interesting new things by analyzing terabyte-sized sets of data.

Funding for this project has been provided by the National Aeronautics and Space Administration (NASA) and the National Science Foundation (NSF).

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