WASHINGTON (States News Service) -- Georgia State University astronomers recently succeeded at combining light collected with two telescopes and then channeled down long vacuum pipes for an innovative, mountain-top array that eventually will have the resolving power of a single lens the size of a football field.
The $13.5 million "interferometric" array, to be comprised ultimately of six such telescopes atop Mount Wilson in California, acts like separate eyeballs that focus on the same object from different angles. It will have the power to see sunspots a few thousand light-years away.
"If you look through just a regular telescope, you won't see many more details than you would with the naked eye. They would still be just flickering lights,'' said Harold McAlister the telescope's lead astronomer and the director of Georgia State University's Center for Angular Resolution Astronomy, or CHARA.
"This is like zooming in on something. You'll be able to see the real shape of the star."
While producing crisp images is still a ways off, CHARA cleared a crucial hurdle a week ago when starlight funneled from the 1 meter-diameter mirrors of two telescopes was successfully bounced to optics in a beam combination barn 656 feet (200 meters) away to yield a rough, squiggly record of three stars' sizes and shapes.
"The really important thing is we've shown that all this hardware works together as it should,'' McAlister said. That hardware includes optical, mechanical and electronic sub-systems, as well as computer software that controls them. "And this is good news."
The first results, called a "fringe," resembled an earthquake readout as produced by a seismograph. The CHARA data will tell astrophysicists and astronomers the sizes and shapes of stars, details of their surfaces and nearby environments, including their planetary systems if they exist.
"Seeing the fringe is like seeing the heart work in a way. If it didn't work, it would've flat-lined," McAlister said.
It took McAlister and a handful of other astronomers 15 years to get funding for the project, expected to be fully functional by 2001. The goal is to combine the power of six sets of mirrors and vacuum tubes to see new stars and planets, as well as study how stars in binary systems orbit each other.
The telescopes, 115 feet (35 meters) apart, each collect and focus starlight into a 5 inch- (127 millimeter-) diameter ray of light, which is projected to a table in the beam combination facility that has photosensitive recording equipment built into it.
Starlight must travel through the vacuum tubes so as not to be bent by turbulent air, McAlister said. The tricky part is getting the light from the separate telescopes to travel through the tubes and to the table simultaneously.
The central station is located in a building next the historic Mount Wilson Observatory. Mount Wilson is where Edwin Hubble discovered in 1929 that the universe is expanding, using the 100 inch (2.54 meters) Hooker Telescope there.
CHARA's additional four telescopes should be installed by the end of this winter, McAlister said, and the entire array could be fully operational in 18 months.
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