The University of Chicago Magazine

Sloan ranges

Ten years have passed since the Sloan Digital Sky Survey’s telescope at Apache Point Observatory in New Mexico captured its first celestial images, brilliantly detailed pictures from the Serpens and Ophiuchus constellations. Since then, the survey—a collaboration of 300 scientists at 25 institutions including Chicago—has continued sweeping the heavens in an endeavor to map a quarter of the sky. So far it has collected data on nearly more than 200 million celestial objects: stars, galaxies, quasars, and other luminous structures. Recorded on magnetic tapes, that data makes its way by special courier to Fermi National Accelerator Laboratory, where it’s funneled to different software pipelines for processing.

Until last year, all the Sloan data simply remained at Fermilab for storage. “But then people started thinking about the hazards of keeping it all in one building,” says Dean Armstrong, AB’03, a systems administrator for University of Chicago Library. “What if something happened at Fermilab?” So last fall, Armstrong and a counterpart from the Johns Hopkins University library traveled to Fermilab’s Batavia campus to discuss the situation, and Fermilab sent the survey’s most recent batch of highly processed data, four terabytes of information. One terabyte, Armstrong explains, equals 1 million megabytes; “Researchers think the survey will total 55 to 60 terabytes when it’s finished. That’s a lot more than will fit in a computer under some astronomer’s desk—which has been the traditional way to keep survey data.”

Housed in three servers in the Reg’s basement, the data—including images like the one above of Cygnus region, an area of the sky that is full of gas, dust, and stars—is available online to scientists around the world through the library’s Web site. The John Crerar Library also runs an online help desk to filter astronomers’ questions. “That’s always been a library’s traditional role,” Armstrong says. “We’ve already got the infrastructure in place.”