Grant to Fund World’s Largest Telescope : Caltech, UC to Join on 400-Inch Device

Plans to build the world’s largest optical telescope, so powerful it could detect a candle’s flame on the surface of the moon, were announced Thursday at Caltech.

The 400-inch instrument, funded by what was described as the largest private grant in history to a scientific project, will be built atop Mauna Kea on the island of Hawaii. The telescope is a carbon copy of one initially envisioned by the University of California, but the university will join Caltech instead in a joint venture funded primarily by a grant from the W. M. Keck Foundation.

It will be essentially the same instrument in the same location as the one planned by the University of California, but the name has been changed to honor the primary donor. What would have been called the Hoffman Observatory under a $36-million grant to the University of California by the Marion O. Hoffman Trust will instead be known as the Keck Telescope under a $70-million grant from the Keck Foundation.

By whatever name, the telescope could offer astronomers their best look yet into the dark corners of the universe, possibly moving mankind closer to understanding the origin of life and celestial bodies.

Caltech was awash with scientists and leading educators Thursday, all of whom seemed eager to brand the telescope as one of the greatest advances since Galileo pointed the first telescope toward the heavens nearly 400 years ago.

“This is a historic occasion,” Caltech President Marvin L. Goldberger said in announcing the grant. He read congratulatory telegrams from Gov. George Deukmejian and President Reagan, who said the project “excites the imagination of anyone who has ever looked up at the stars in wonderment.” Goldberger was joined at the press conference by UC President David P. Gardner and Howard B. Keck and Julian O. von Kalinowski, chairman and director, respectively, of the Keck Foundation.

The Keck grant will cover nearly the entire cost of construction of the $85-million project. About $15 million is being contributed by the two schools.

The final contracts covering the grant are expected to be signed within the next few weeks. At that point, Gardner said, the University of California will release the Hoffman Trust from its pledge.

The instrument, 400 inches in diameter, will be twice the size and four times as powerful as the Hale Telescope on Mt. Palomar in San Diego County, currently the largest optical telescope in the United States. It will also be nearly twice the size of a 236-inch telescope in the Soviet Union, currently the world’s largest.

While there are larger radio telescopes that measure radio energy, this will be by far the biggest optical instrument, producing photographs of far greater brilliance than any other telescope anywhere in the world.

It will take more than six years to build the observatory on land owned by the University of Hawaii, which will also have access to the instrument. Construction is scheduled to begin next year on a 13,600-foot ridge on Mauna Kea, described by Goldberger as “the world’s greatest astronomical site.”

It will work in concert with the Space Telescope, scheduled to be launched into orbit from a space shuttle in 1986.

The Space Telescope, which will operate above the Earth’s atmosphere, far removed from the detrimental effects of air pollution and background lighting, will be able to pick out celestial objects that are too faint to be detected by earth bound telescopes.

However, the huge mirrors of the Keck Telescope will have far greater light-gathering capabilities than the smaller Space Telescope, and scientists who attended Thursday’s press conference said the Keck instrument will be large enough to permit detailed analysis of faint targets that are found by the orbiting system.

Goldberger said the telescope will help scientists study objects that are 12 billion light years away from Earth, possibly yielding clues to the origin of the universe.

Space is so vast that even light, traveling at 186,000 miles per second, moves relatively slowly. Thus a large telescope becomes sort of a time machine, capturing images of celestial bodies not as they are today, but as they were billions and billions of years ago.

Scientists generally believe the universe is about 15 billion years old, Goldberger said, so a telescope that can see 12 billion light years away “can look back three-fourths of the way to the birth of the universe.” (A light year is the distance light travels in a year, nearly 5.9 trillion miles.)

The telescope should thus help astronomers learn more about “what the state of the universe was much closer to the time of creation,” Goldberger said.

Bigger telescopes have long been the dream of astronomers, but until recently, it was thought that the Palomar scope would never be surpassed because of technological limitations. Scientists thus concentrated on enhancing the images they received, rather than increasing the size of the instruments.

In the early days, only about 1% of the light that reached a telescope could be captured by the mirror. Computers and photoelectric detectors have increased that yield up to 80%, but the amount of light captured is still limited by the size of the mirror. The size of the mirror, in turn, is limited by the fact that it is made of glass. A large mirror can deform because of various forces, including gravity, thus restricting the practical size of a telescope.

Instead of using one piece of large glass for its huge mirror, the Keck Telescope will use 36 hexagonal mirrors, each six feet wide and fitted together in what looks like a honeycomb.

Jerry Nelson, professor of astronomy at UC Berkeley and project scientist for the telescope, said in an interview that each mirror will be supported by three motorized pistons that will keep all the components acting as a single instrument, making adjustments to account for the almost immeasurable effect of such things as gravitational deformation.

Nelson said the system can adjust each mirror one-thousandth the diameter of a human hair about 300 times per second, thus keeping flaws to a minimum.

He said Mauna Kea, an extinct volcano, was selected for the telescope because it is relatively free of pollution.

“There’s no guarantee that it will remain extinct,” he said, “but the last eruption was several thousand years ago.”

Like all large, modern telescopes, the Keck Telescope will essentially be used as a camera lens, rather than an instrument for astronomers to physically look through. A camera is capable of capturing far more light than the human eye, increasing the light-gathering capabilities of the instrument about 50-fold, Nelson said.

That also means that it should be possible to transmit photos from the telescope to major research centers around the world, thus permitting scientists to make full use of the instrument without having to leave their normal work stations.

“We’d like to save them the cost of a plane ticket,” Nelson quipped.

The effort to build the telescope began at the University of California, where scientists on various campuses had been working on the new design. In December, 1983, the widow of Maximilian Hoffman, a wealthy foreign car importer, met with Gardner.

She told the UC president that she was interesting in giving the university $36 million to help finance a telescope that would be named in honor of her husband. The day after the meeting, Marion Hoffman died, but her will made it clear that the money was to be used for that purpose, Gardner said Thursday.

Last May, Gardner announced plans to build the Hoffman Observatory if enough additional funds could be found. He said then that the University of California might join with some other institution to help finance the project, but he declined to say which university was under consideration.

During the press conference Thursday, he said the difference between the grant and the expected cost of the project proved substantial, and when he turned to Goldberger, the Caltech president came up with the Keck proposal.

The result was the pooling of efforts and resources by both institutions, aided by $70 million from the foundation.

The two schools, Gardner said, “joined together to accomplish what neither could do alone.”