Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: MONDAY, May 21, 1990 TAG: 9005210070
SECTION: NATIONAL/INTERNATIONAL PAGE: A-1 EDITION: METRO
SOURCE: The Baltimore Sun
DATELINE: GREENBELT, MD. LENGTH: Medium
As astronomers and NASA officials anxiously watched computer screens at the Goddard Space Flight Center here, their headstrong, $1.5 billion telescope sent home a black-and-white "first-light" image they applauded as "fantastic," "beautiful" and "gorgeous."
Even before the April 24 launch of Hubble into its 380-mile-high orbit, officials had repeatedly cautioned that such a first-light exposure and transmission was just a focus, or engineering, test.
"After being launched just over three weeks ago, the Hubble Space Telescope is in wondrous good shape," said Dr. James Westphal, the California Institute of Technology scientist whose high-tech camera grabbed Hubble's first snapshot.
Known as the wide-field-planetary camera, it blinked open at 11:12 a.m. on a star cluster in the southern constellation Carina, 1,260 light-years away in Earth's Milky Way galaxy.
And, in one historic 30-second exposure, it eased doubts about Hubble's ability to perform as predicted, doubts raised by many start-up problems encountered in the first weeks of operation.
"I'm extremely pleased with the pace with which we're bringing this telescope into operation," said Dr. Lennard Fisk, associate administrator for space science and applications at the National Aeronautics and Space Administration.
Although there were actually four "first" images taken - including a one-second exposure and two internal test shots - it was the 30-second exposure that gave NASA an unexpected bonus to compare to an image of the same star cluster taken from Earth.
The open-star cluster, known as NGC3532, was chosen to provide many bright stars in a wide enough area to test the camera's field of view.
Officials said that it would take months to fine-tune the focus and pointing system to observe celestial objects at the edge of the universe with 10 times the clarity of ground-based telescope.
One reason for the caution was that the wide-field-planetary camera's four sensitive light detectors - known as charge-coupled devices - have not yet been cooled to their optimum operating temperature of minus 140 degrees Fahrenheit.
The image captured Sunday was expected to exhibit a resolution no better than 1.5 arc seconds, compared with the ultimate goal of 0.1 arc seconds. There are 3,600 arc seconds in a degree, and the full moon as seen from Earth appears to be 1,800 arc seconds in width.
But Westphal's camera - the premier instrument aboard Hubble, with the equivalent of both a wide-angle and telephoto lens - delivered 0.7 arc seconds.
Ground telescopes have rarely achieved resolution as great as 0.3 arc seconds. They routinely operate in the neighborhood of 1.0 arc second because of limitations imposed by the turbulent atmosphere.
And the payoff was obvious Sunday in the image taped on the telescope's on-board recorders before lunchtime and transmitted to Earth through a NASA communications satellite.
It clearly showed the double star in the open cluster, seen as just an oblong blob on a three-second exposure taken with the 100-inch telescope at the Las Campanas Observatory in Chile.
"Already we've been able to tell something we couldn't tell from the ground," said Westphal, pointing out the two distinct stars visible when the Hubble image was seen on computer monitors. Some of that detail was lost in the reproductions made available for newspapers.
As pleased as project officials were by the success of first light, the purpose was not scientific discovery.
"The next several weeks and months will be dedicated to getting this system tweaked up and at peak performance," said Jean Olivier, deputy project manager for Hubble at Marshall Space Flight Center in Alabama.
The process of "orbital verification" is approximately 10 days behind schedule because of the earlier problems.
It will be followed by five months of "science verification" in which the five instruments aboard will be calibrated and tested by the 56 scientists who built them.
Only then will routine observations begin by astronomers from around the world.
by CNB