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Twin Telescopes With Near-Infrared "Eyes" Begin All-Sky Survey

Donald Savage
Headquarters, Washington, DC                September 17, 1997
(Phone:  202/358-1547)

Jane Platt
Jet Propulsion Laboratory, Pasadena, CA
(Phone:  818/354-0880)

RELEASE:  97-205


           The first of a pair of new telescopes, funded primarily 
by NASA, has begun an ambitious three-and-a-half year near-
infrared survey of the entire celestial sky, peering through the 
curtain of interstellar dust in the Milky Way galaxy.

           The Two-Micron All-Sky Survey (2MASS), based at the 
University of Massachusetts, Amherst, MA, features two 1.3-meter 
telescopes, one at a Smithsonian Astrophysical Observatory site 
atop Mount Hopkins, near Tucson, AZ, and the other at a National 
Optical Astronomy Observatories site in Cerro Tololo, Chile.

           "The sky survey catalogues produced 100 years ago are 
still useful to astronomers," said Project Manager Rae Stiening.  
"We expect this new, greatly updated survey will be an invaluable 
resource for the next 100 years."   

          "Preliminary observations by 2MASS are already 
suggesting new infrared sources will be discovered," said Program 
Manager Dr. Michael Klein at NASA's Jet Propulsion Laboratory, 
Pasadena, CA.  "Some of these will be targets for detailed studies 
for future space observatories, like the Advanced X-Ray Facility 
(AXAF), the Space Infrared Telescope Facility and the Next 
Generation Space Telescope."

          The survey is designed to catalogue one million galaxies 
and 300 million stars in the local universe, along with quasars, 
which are strong, extremely bright radio sources, and galaxies 
with black holes, the intriguing entities with gravity so powerful 
not even light can escape.  

          2MASS will observe many known asteroids and possibly 
some comets, and it is uniquely sensitive to exotic objects like 
brown dwarfs, which lack the mass needed to ignite and become 
full-fledged stars.  The telescopes are equipped with near-
infrared detector arrays that will provide the most complete 
census to date of cool stars in the Milky Way galaxy and provide 
new data for detailed studies of the galactic structure.  Near-
infrared emission is at wavelengths roughly two-to-four times 
longer than visible light and permits astronomers to "see through" 
the obscuring effects of interstellar dust in the Milky Way galaxy.

           As Stiening explained, "Sunsets on Earth look reddish 
because only red light makes it through the dust in our 
atmosphere.  Infrared observations enable us to penetrate the dust 
in our galaxy and other galaxies and, therefore, they provide a 
much clearer view of interior regions."

           The 2MASS survey will measure accurately the positions 
and infrared brightness of stars and galaxies.  Combined with 
complementary ground-based red shift surveys, the 2MASS extra-
galactic data will provide a three-dimensional view of large-scale 
structures in the local universe.  The enabling technology for 
this survey is the breakthrough in large-format infrared detector 
arrays.  These technologies, funded through the U.S. Department of 
Defense and NASA, are being adapted for astronomical purposes to 
increase sensitivity dramatically.  It's expected the new survey 
will be some 25,000 times more sensitive than a precursor survey 
at the California Institute of Technology, Pasadena, CA, nearly 30 
years ago.  2MASS uses the type of detectors developed for the 
Near Infrared Camera and Multi Object Spectrometer on NASA's 
Hubble Space Telescope.

           "Observing time at most telescopes is divided among a 
variety of scientific programs using a suite of different 
instruments.  2MASS telescopes will be completely dedicated to 
mapping the sky using one instrument, a three-color infrared 
camera," said Principal Investigator Dr. Michael Skrutskie, a 
University of Massachusetts physics and astronomy professor, who 
leads the science working group that will evaluate the data 
products.  He also managed the design and fabrication effort for 
the infrared cameras, which are attached to an identical pair of 

           Data will be processed at JPL's Infrared Processing and 
Analysis Center  at Caltech.  Every two nights, the center will 
process 60 gigabytes of data, which is more data than processed 
during the entire Infrared Astronomy Satellite (IRAS) mission of 1983.

          The 2MASS survey is funded by NASA's Office of  Space 
Science, the National Science Foundation, the U.S. Naval 
Observatory and the University of Massachusetts. JPL is managing 
the program for  NASA's Office of Space Science, Washington, DC.   
Additional information and images are available at the 2MASS 
website at URL: 


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