Astronomers working at the Large Binocular Telescope on Mount Graham released a flurry of scientific papers Thursday to highlight images that, as predicted, are three times sharper than those gathered by the Hubble Space Telescope, using just one of the massive telescope's binocular eyes.
For the first scientific run on the telescope, University of Arizona astronomers targeted known objects and observed them in the near-infrared wavelengths that they expected to produce the best results.
The resulting images were astounding, said Steward Observatory astronomer Laird Close. The LBT, fitted with an adaptive-optics system that compensates for the blurring effect of Earth's atmosphere, produced images clearer than those he had previously taken with some of the world's largest telescopes.
"It's pretty exciting," said Close. "Arizona now has, if not the world's best telescope, certainly one of the world's most powerful telescopes." Adaptive optics erases the advantage of space telescopes, he said.
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The view afforded by the LBT and its revolutionary adaptive-optics system gave Close the best look yet at a star system at the center of the Orion nebula that he has studied for more than 15 years.
It enabled him to make measurements proving that five stars in an area called the trapezium are orbiting one another. Close compared the images from the 8.4-meter LBT to ones taken previously with the 8-meter Gemini telescope in Hawaii and the 6.5-meter MMT Telescope on Mount Hopkins, south of Tucson. (A meter is slightly more than 3 feet.)
He was able to measure their movement around one another, a feat possible only with huge telescopes. "Imagine you had a dime 2,000 miles away. What we're able to do is see that dime move the width of itself every few years. That's how little motion these stars are making."
Close said he had hoped to discover "some brand new objects," even though he knew chances were slim. "We're talking about Orion, right. It's been looked at by every telescope forever."
Close said his observation of "my favorite stars dancing" bolsters theories about star formation with visual evidence.
Steward astronomer Andy Skemer, who studies exoplanets, also chose known objects for study. "In our very limited amount of time, we had to make sure we had a planet," he said.
Skemer turned the telescope's vision-corrected big eye on HR8799, a young star in the constellation Pegasus where astronomers found the first known multiplanet system outside our solar system in 2008.
Skemer said he got a much better look at the planets than the astronomers who found it. His view trumps images from the Gemini telescope and the even-larger Keck Telescope in Hawaii, Skemer said.
"They are more complicated than we originally thought," Skemer said, with astronomers now thinking that the four planets are covered in clouds of varying intensity.
The LBT was especially useful for looking at the planet closest to the star, Skemer said.
"The reason you build a system like this is to see very faint planets near their very bright stars. We can see things 10,000 times fainter than the star, separated by a quarter arcsecond," Skemer said.
Steward astronomer T.J. Rodigas chose to observe a debris desk around a relatively nearby star (HD15115) that had been observed using the Keck and the Hubble Space Telescope. Rodigas used the LBT to observe it "at the longest wavelengths ever for a debris disk" and found it quite different from those earlier impressions.
"We found large dust grains in this debris disk previously thought to have small dust grains," said Rodigas.
The debris disk is also more symmetrical than previously thought and grayish in color rather than blue, he said.
The four papers, all published online Wednesday, have multiple authors from the UA's Steward Observatory and its partners in the LBT.
All four papers credit Piero Salinari of Arcetri Observatory for his leadership in development of the adaptive secondary mirrors.
LBT Director Richard Green said the papers and images, while not outright discoveries, add immensely to theories of planet and star formation. These first science results presage a productive future for the LBT, Green said.
The twin primary mirrors are both now fitted with adaptive secondaries. Work on combining the light from the two mirrors begins in earnest this spring.
Combining the light-gathering properties of both 8.4-meter mirrors will give it the resolution of a 22.8-meter (75-foot) telescope. At that point, astronomers expect it to have 10 times the resolution of the Hubble Space Telescope.
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MORE INFO
Images, information and scientific papers available from www.lbto.org
ABOUT THE LBT'S ADAPTIVE OPTICS
The First Light Adaptive Optics system employs a deformable 36-inch mirror only 0.06 inch thick, with 672 magnets glued to the back that can change its shape every one-thousandth of a second. It was developed by the University of Arizona's Steward Observatory and partners at the Arcetri Observatory of the Italian National Institute of Astrophysics, where it was built.
During tests in 2010, the new secondary mirror routinely erased 60 percent to 80 percent of atmospheric disturbance and went as high as 84 percent distortion-free. Similar results were achieved during the science run last fall.
Among the improvements over earlier adaptive-optics systems, this mirror is more malleable and serves as the secondary mirror for the telescope, creating a more direct path for the light gathered by the main mirror and avoiding the "background noise" caused by separate optical systems.
The Large Binocular Telescope now has the system installed above both its primary mirrors.
The next improvement is to add the capacity to link the giant mirrors together in binocular mode. That will give the LBT the resolving power of a telescope mirror 22.8 meters (75 feet) in diameter. It is expected to produce images 10 times clearer than the Hubble Space Telescope.
DID YOU KNOW?
Congress approved construction of the three telescopes of the Mount Graham International Observatory in 1988, but controversy and lawsuits continued over the endangered Mount Graham red squirrel and a claim by Apaches that the peaks of the Pinaleño Mountains are sacred to them. The Clark Peak Fire burned to within 200 yards of the telescopes in 1996, and in 2004 the Nuttall Complex again threatened the Large Binocular Telescope.
The second of the two giant mirrors of the LBT saw first light in December 2007.
Contact reporter Tom Beal at tbeal@azstarnet.com or 573-4158.
