New lease on life for Hubble
2002-06-06 11:17
Albuquerque, Canada - A Hubble Space Telescope camera that was broken for more than three years has roared back to life after repairs, peering through cosmic dust to snap a four-galaxy wreck and a golden star-forming ring, scientists said on Wednesday.
The repaired camera is 30% to 40% more sensitive than it was before it broke, and one researcher said it will let astronomers do more science in less time.
Astronomers were predictably ecstatic.
"This is really fantastic ... Studying star and planet formation ... with this new capability is going to revolutionise a very great deal of what we do," said Anneila Sargent, president of the American Astronomical Society, which is meeting this week in Albuquerque. "It really is like looking with a different kind of eye."
"The Hubble Space Telescope is open again for infrared business," Ed Cheng of Nasa's Goddard Space Flight Centre told a news conference.
The repaired Near Infrared Camera and Multi-Object Spectrometer (Nicmos) lets astronomers look through cosmic dust where the real action often is hidden: The birth of stars, the collision of galaxies, and other seminal celestial events.
Other cameras aboard the orbiting Hubble craft can find these regions, but much of what they see is the dusty veil; with Nicmos, astronomers can see beyond the dust because the camera monitors infrared light instead of visible light.
Looking at the universe in infrared light also enables scientists to see more distant and older objects, billions of years old, perhaps approaching the time soon after the theoretical Big Bang that gave birth to the cosmos.
An image of the four-galaxy collision was produced with Nicmos and with the newly installed Advanced Camera for Surveys (ACS), which looks at the universe in visible light.
ACS saw the area, but could not glimpse any detail in the golden heart of the jewel-toned blue collision site. For that, Nicmos was necessary.
Fuzzy brown stripe reveals golden ring
In another case, where another Hubble camera saw only a fuzzy brown stripe representing a galaxy viewed from the side, Nicmos saw a glowing yellow area. Using a hydrogen light filter, Nicmos saw more, according to Daniela Calzetti of the Space Telescope Science Institute.
"We pierced all the way into the dust to the nucleus of this galaxy," Calzetti told a news conference. "This flattened yellow structure that we see here (at the centre of the image) is what we think is a ring of star formation surrounding the nucleus."
A third release by the National Aeronautics and Space Administration compared a spectacular image taken by ACS of the Cone Nebula with the same shot taken by Nicmos. Where ACS saw billows of red dust clouds, Nicmos captured about 10 stars.
These three images were test shots from the revamped camera, which was repaired by space shuttle astronauts in March.
Nicmos was installed on Hubble in 1997 but stopped working in 1999, when the solid nitrogen used to keep its infrared detectors cold evaporated - about two years before scientists expected.
The repair replaced that earlier cooling system with a mechanical cryo-cooler, roughly the equivalent of replacing an old-fashioned ice box with a modern refrigerator.
The new cooler pumps super-cold neon gas through Nicmos's internal plumbing, with three high-tech turbines the size of matchsticks at its core.
These turbines let scientists adjust the temperature of the infrared sensors and allow the instrument to operate at the optimum temperature, about minus 321 degrees Fahrenheit. It used to operate at minus 351 Fahrenheit.
"Overall I believe we have a better Nicmos than we had in 1997-98," Calzetti said. "Because the cryo-coolers allow us to set the temperature to ... actually give us the peak of performance."
She said the camera is about 30% to 40% more sensitive than in the past. "This means that for most science this translates directly in a comparable increase in the observations. ... You can have the same science in less time," Calzetti said.