"Any computer with a web browser can be transformed into a desktop observatory," said Dr. Michael Skrutskie, of the University of Massachusetts, principal investigator of the sky survey, which has scanned the nighttime sky and produced an online image potpourri of half a million galaxies and 162 million stars.

"The general public can see a menagerie of objects in infrared wavelengths that they couldn't see in any other way," said project scientist Dr. Roc Cutri. The 1.9 million images would fill 6,000 CD-ROMs, equivalent to 4,000 gigabytes or four terabytes of computer hard disk space.

The images were gathered by the Two-Micron All Sky Survey (2MASS), the most thorough census of stars ever made. The survey detects infrared wavelengths that are beyond the red light in the rainbow of visible colors. Infrared light penetrates the gas and dust in our galaxy and is particularly effective for detecting the heat of very cool objects not visible with optical telescopes.

In order to cover the entire sky, the 2MASS survey uses two highly automated, 51-inch (1.3-meter) diameter telescopes, one at Mount Hopkins, AZ., the other at the NSF Cerro Tololo Inter- American Observatory, Chile.

Operations for 2MASS began in 1997. Its catalogs will contain more than 300 million objects by the time observations are concluded in 2001. Final processing of the data and release to the public will be complete by 2003.

Already, 2MASS data have uncovered numerous stars with characteristics so unique that astronomers had to revise a century-old classification system of known types of stars.

Astronomers armed with 2MASS data also discovered the coolest brown dwarfs, or failed stars, known to date. They also detected previously unknown star clusters within, and galaxies beyond, our own Milky Way, and have mapped new star-birth regions. In the distant reaches of the universe, 2MASS discovered a new population of dust-obscured active galaxies, quasars and super-massive black holes.

"The current release is based on a volume of data several hundred times larger than that contained in the human genome," said Skrutskie. "Astronomers will become cosmic geneticists, searching out patterns in these sky maps to decode the structure and origin of the Milky Way and the surrounding nearby universe."

The 2MASS project is a collaborative effort between the University of Massachusetts, Amherst, and the Infrared Processing and Analysis Center (IPAC) in Pasadena, CA, operated by NASA's Jet Propulsion Laboratory (JPL) and the California Institute of Technology, both in Pasadena. Cutri is affiliated with IPAC, which combines and processes 2MASS images into usable data. The University of Massachusetts was responsible for the development and construction of the 2MASS telescopes and cameras and currently manages the collection of survey data.

Part of NASA's Origins Program, 2MASS is funded by NASA's Office of Space Science and the National Science Foundation. 2MASS results will benefit future Origins missions, including the Space Infrared Telescope Facility and the Next Generation Space Telescope, and will also help scientists plan observations for the Hubble Space Telescope and the Stratospheric Observatory for Infrared Astronomy. JPL manages the program for NASA's Office of Space Science, Washington, DC. JPL is a division of Caltech.