Caltech to Construct Twin to World’s Largest Telescope : Astronomy: A $74.6-million Keck Foundation grant will fund most of the project. Scientists hope the Hawaii facility will provide new details about distant galaxies.
Caltech will build a twin of the world’s most sophisticated optical telescope, creating a facility that will enable astronomers to view galaxies as they were only a billion years after the creation of the universe, as the result of a $74.6-million grant from the W. M. Keck Foundation, university and foundation officials said Friday.
The telescope will be identical to the world’s largest telescope, the 10-meter Keck Telescope, nearing completion atop the extinct Mauna Kea volcano in Hawaii, where astronomical viewing conditions are the best in the world. The telescopes will be situated next to each other and run jointly by Caltech and UCLA.
Operating together, the two telescopes will have eight times the light-collecting ability of the 200-inch Hale Telescope at Palomar Observatory and will be able to observe galaxies so distant that they only appear as faint blobs of blue light in existing telescopes.
The Keck Foundation also provided $70 million for the first telescope, and the two grants together are by far the “largest commitment by a philanthropic organization to a scientific endeavor,” said foundation head Howard B. Keck.
The grant will pay for 80% of the estimated $93.3-million cost of the new telescope. Caltech President Thomas E. Everhart said the university is looking for a partner to finance the remaining sum. Jet Propulsion Laboratory Director Edward C. Stone said the National Aeronautics and Space Administration is the most likely source of the money, but that other organizations had also expressed interest.
The telescope has a radical new design that is being tested for the first time in Keck I. Existing optical telescopes generally have a single large mirror, but most experts agree that it is virtually impossible to grind a mirror significantly larger than that on the Hale.
In place of a single mirror, the Keck telescopes will use a computer-driven array of 36 hexagonal mirrors that can be precisely focused on the same astronomical object, thereby providing the equivalent of a mirror 33 feet in diameter.
Everhart said Keck I started with two unproven technologies: a new technique for precisely grinding the mirrors and the computer programming for alignment of mirrors.
He said both technologies were proved when Keck I achieved “first light”--the first imaging of an astronomical object--with the first nine of its 36 mirrors last November. It is important to continue immediately with the second telescope, he added, while the team that ground the first mirrors is in place so that a new team does not have to be trained.
More important, Stone said, will be the great advance in technology when the images from the two telescopes are joined together by a technique called interferometery, in which the outputs of the two telescopes are combined electronically.
Unless a galaxy being observed is directly overhead, light from it must travel slightly further to one telescope than to the other. Thus the light waves received are to some extent out of phase with each other. As the Earth rotates, this phase difference changes, and by measuring that change in phase--the process of interferometry--the twin telescopes are able to determine the position of the light source very accurately, thereby producing much sharper images.
“Gathering twice as much light will make possible the study of fainter, more distant galaxies, quasars and primitive galaxies as they appeared in the first few billion years of the universe,” Stone said.
“With the greatly improved spatial resolution, it will be possible to study the interior of star formation regions and delineate the distribution of matter,” he said. “The detail these telescopes will be able to discern will be comparable to seeing a car’s headlights separately from a distance of 16,000 miles.”
Astronomers hope the two telescopes will be able, for the first time, to identify planets orbiting other stars. They “will have the power to identify the presence of warm Jupiter-sized bodies in orbit around the 100 nearest stars,” Stone said.
Although the mirrors in the Keck telescopes are larger than that in the $1.5-billion Hubble Space Telescope, Hubble should have been able to see more distant objects because it orbits above the distorting effects of Earth’s atmosphere. But its 2.4-meter mirror is flawed.
After the Hubble is repaired by space shuttle astronauts in 1993, it will see objects more clearly than the Keck telescopes, Stone said. But the Kecks will be superior in their ability to let astronomers identify distant objects by analyzing their composition, speed and precise distance in time and space, he said.
The Keck Foundation was created in 1954 by its namesake, the founder of Superior Oil Co. His son, Howard Keck, has devoted his efforts to running the foundation since Superior was sold to Mobil Corp. in 1984. The foundation’s assets total $726.8 million.
Ironically, Keck said at a Friday news conference: “I really have no interest in astronomy. I’m just interested in making worthwhile scientific grants.”
This grant is very worthwhile, Everhart concluded. The twin telescopes “will answer many questions about the universe in which we live” and “enrich every single human being for as long as civilization survives.”
Scanning the Skies A new telescope, funded by the W.M. Keck Foundation and to be finished in 1996, will be a twin of the 10-meter Keck Telescope now nearing completion in Hawaii. Like Keck 1, its distinguishing feature is the array of 36 computer-controlled mirrors (center of drawing, above). Together, the mirrors will have the capabilities of a telescope with a mirror twice the sizeof the 200-inch Hale Telescope at Palomar Observatory. Because of improvements in telescope design,though, the dome is actually smaller than that at Palomar. Light from the two telescopes will be beamed though the tunnel (gray area below the observatory) and joined so the instrument will have eight times the light-gathering ability of the Hale.
