Sky Survey Project Could Open Up The Universe `By Magnitudes'
CD-ROM will allow light-speed research using five-color images
PEOPLE who search the night sky - either professionally or for pleasure - could soon have at their fingertips a map of the heavens incredibly more detailed than anything available before.
Like much in astronomy, ``soon'' has to be taken in relative terms. The scheduled completion date for the Sloan Digital Sky Survey is 2001. But the project, undertaken by the Astrophysical Research Consortium, which includes Princeton University, is already well under way.
The initial steps have been planning, designing, and building, with the ``construction phase'' now begun. Three major items have to be built: a new 100-inch telescope for the consortium's Apache Point, N.M., observatory, the camera that will use an array of large silicon chips called CCDs (charge-coupled devices) rather than photographic plates, and the special double spectrograph that will record the light spectra coming from celestial objects and thus enable astronomers to estimate their distances.
When the project is complete, the astronomers will start gathering data about the sky at a pace and depth that will be ``magnitudes better'' than previous sky surveys, says Jeremiah Ostriker, head of Princeton's department of astrophysical sciences.
The information coming off the new telescope will be measured digitally in ``terabytes'' (a million million), explains Princeton astrophysicist Gillian Knapp. When all that is put in a form accessible to someone at a computer terminal, such as on a CD-ROM, researchers will be able to do with a ``click'' what before could have taken months, even years - such as find all the objects of comparable brightness to a star or galaxy under study.
``In astronomy,'' Mr. Ostriker says, ``surveys have produced a huge amount of what we know. If we can design something to see more of the universe, important things will be discovered. It happens every time.''
As an example, he points out what happened when radio astronomy was developed after World War II. ``A completely new universe'' opened up as the radiation, not just the visible light, coming from distant parts of the universe was detected and analyzed.
Ostriker says the Sloan survey - named after the Alfred P. Sloan Foundation, which has contributed $8 million of the $18 million capital cost of the survey - could have a similar impact.