The Space Infrared Telescope Facility, NASA's fourth and final Great Observatory, has been successfully focused. This crucial milestone which will enable the observatory's infrared eyes to see the cosmos in clear detail was achieved after a series of delicate adjustments were made to the telescope's secondary mirror.

An artist's concept of SIRTF. Credit: NASA/JPL/Caltech

Since launch on Aug. 25, the Space Infrared Telescope Facility has performed as expected, proceeding through in-orbit checkout activities on schedule. In addition to achieving final focus, the telescope has cooled to an operating temperature of approximately 5 Kelvin (-268 Celsius or -451 Fahrenheit). This cold temperature will allow the observatory to detect the infrared radiation, or heat, from celestial objects without picking up its own infrared signature.

"The science community now has an outstanding observatory with which to study the universe," said Dr. Michael Werner, project scientist for the mission at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We are eager to complete the fine-tuning of the observatory and begin the science program."

In-orbit checkout activities are scheduled to continue for 14 more days, after which a one-month science verification phase will occur. Following this, the science program will begin.

From its innovative Earth-trailing orbit around the Sun, the Space Infrared Telescope Facility will pierce the dusty darkness enshrouding much of the universe, revealing galaxies billions of light years away; brown dwarfs, or failed stars; and planet-forming discs around stars.

JPL, a division of the California Institute of Technology in Pasadena, manages the Space Infrared Telescope Facility for NASA's Office of Space Science, Washington, D.C.