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World's largest amateur telescope

20 core volunteers in a Santa Clara warehouse lift, tweak and polish and polish and polish and polish and polish. Group 70 wants to build the world's largest amateur telescope with a 6-foot main mirror, 10 times the size of typical amateur telescopes, sending Internet images. It started in 1998 with an astronomy magazine classified. For sale: 3,000-pound glass disc poured in 1938 as never-used raw material for a telescope, stored in Australia. An astronomy fan saw the ad. E-mail did most of the rest. A meeting was set, forming Group 70 (members first thought the disc was 70 inches) raising $25,000 among themselves to buy the glass. No Internet project, it's more like the Colorado River etching the Grand Canyon. Work started pre-Pentium. Before eBay. 6-month product cycles? Lucky to do it in 1 lifetime. It's slow work, forming the rough glass into a parabola by grinding and then polishing, polishing, polishing, slower still with volunteer labor and scrap equipment. The glass lies on a table. The jury-rigged polisher sweeps back and forth. The machine looks like a car wreck, made of motorcycle chains, a trailer hitch, free weights and junked metal. Hour after hour, micron by micron, it works. It's best to think ahead to when the glass will be an aid to view the heavens from home computers. Polishing will continue for months. Then a smaller mirror needs to be polished. Obstacles include where to put the telescope, maybe northern California, and dwindling money. Group 70 accepts tax-deductible donations. The telescope is years away.

BIG ISLAND HIGHS

14,000 ft ASL Mauna Kea (White Mtn) part Hawaii, part space

13,796-ft dormant volcano Mauna Kea, Hawaii's highest peak. Atmospheric pressure 60% of ASL. Less oxygen = headaches, sleepiness, nausea, clouded judgment. Not for pregnant women, under 16 or with heart or lung problems. Car rentals don't allow their cars on Observatory Road. An unpaved stretch between visitor center and summit is for 4-wheel-drive. Weather changes rapidly at higher elevations, with 100 MPH winds and whiteouts from blowing snow. Why leave beaches for thin air? Mauna Kea, world's greatest astronomy place, is above 40% of Earth's atmosphere and 98% of its water vapor. Mauna Kea's height and distance from city lights let astronomers see galaxies 12 billion light years away. Public stargazing Thurs - Sun nights when 9,300-ft Onizuka Center for International Astronomy Visitor Information Station, named for Hawaiian astronaut Ellison Onizuka, killed in the 1986 Challenger disaster, opens.

The center has a jumbled collection of telescope parts, posters, space junk, videos. Clothes, mostly jackets, are for people in shorts and Hawaiian shirts. 85 Kailua-Kona coast degrees change to 35 Mauna Kea degrees. 8 miles from the visitors' center, including 5 miles of dirt and gravel road, an otherworldly landscape appears, volcanic and desolate, with snow wherever the sun won't shine brightly. Red and black volcanic dirt plus the dozen or so telescope buildings in all shapes, sizes and colors resemble 1950s sci-fi Mars.

These foreboding fortresses, complete silence and lack of vegetation, are eerie. It could be the thin air. The telescopes are several stories high, built 1968 - 1999, including optical, infrared and millimeter/sub-millimeter telescopes and the Very Long Baseline Array. Without brochures visitors are clueless. Most have no signs and none welcoming the public, except the W M Keck Observatory containing the twin Keck I and Keck II, 10-meter, 36-mirror telescopes seeing far into space's vast recesses. Keck's public gallery has brief visual explanations of the telescopes and photos they took. Despite clean restrooms you still feel like an interloper, with no guides or guards. A cavernous room holds one of the Keck telescopes. Machinery, supplies and equipment on the concrete floor convince you you shouldn't be there. Snap a few photos and go back out into the cold. Summit tours are available on weekends, weather permitting, giving a much clearer picture of work done there.

Mauna Kea offers stunning vistas of clouds below. Above it's clear. Despite warnings of impending doom the only effects of Mauna Kea's height is unsteadiness when exiting your car, like one mai tai too many. The cold air quickly sobers you. Keep the window open to acclimate to the thin air. Spend a half hour at the visitor's center. Drink lots of water. 55-mile Saddle Road, named for the plateau's shape between long-dormant Mauna Kea and still active 13,680-foot Mauna Loa, extends from near the Kohala Coast to Hilo. A 4x4 Jeep Grand Cherokee rents for $120 a day at Harper's near Kona International Airport or in Hilo. Harper's is serious about its cars. Rather than toss you the keys they lecture you and watch you read the disclaimers. They roll a mirror under the Jeep to make sure the underbody wasn't damaged by previous renters.

The 150-mile round trip from Kona takes a long half-day to complete. Not poolside service Hawaii, Saddle Road has no gas stations, restaurants or stores. Phones and restrooms are few and far between. After passing through range lands you drive through the Pohakuloa U S Army Training Area where signs warn of live ammo. You might meet a caravan of military vehicles. Mauna Kea State Park, 5 miles west of the Mauna Kea turnoff, rents cabins well-maintained for hiking. Padlocked bathrooms make it less inviting. Landscape moves from paniolo pasture to barren desert to the Pacific's only glaciers. Mauna Kea and Mauna Loa views vary but these aren't dramatic peaks visually. Still, photo ops are many. Wise travelers bring water, a cell phone, picnic lunch, film. When adventure travel means biking, snowboarding, hang-gliding available on Mauna Kea, driving there and walking around qualifies too.

LINKS University of Hawaii Tour Mauna Kea

UC Santa Cruz and Caltech, designers of Keck's telescopes, ponder a telescope triple the size of today's

Telescope dreams are as boundless as the universe. Wanting views of faint planets in faraway galaxies, and new technology making it possible, scientists compete to create Jovian-sized megascopes, giving more light to study objects fainter, farther away or with higher resolution. Gargantuan OverWhelmingly Large OWL telescope with keen night vision, built like the Kecks but 10 times larger, its primary mirror bigger than a football field, lives in a structure as big as Egypt's Great Pyramid. Space telescopes with multiple orbiting parts spread miles apart, with improved technology for single- and segmented-mirror designs on the ground, hook up several smaller scopes to work together. Current generation telescopes grow bigger and better by science quests disagreeing on the most practical approach. Technological hurdles are solvable. With enough work and money it's not too soon to think of.

The dream telescope could cost $300 - $400 million. On Mauna Kea or on mountains in Africa or Chile it would gather 10 times as much light as each Keck and produce images 3 times sharper. Bigger telescopes doing deep-space observation free smaller telescopes to view nearer objects. Telescopes get bigger ever since Galileo Galilei first trained his 1 1/2-inch refractor on the heavens, using a design similar to telephoto camera lenses today. Modern observatories use Isaac Newton's reflector design: gather the image in a large, concave mirror at the base and reflect it back to viewers by smaller mirrors.

With 1948's 16 1/2-foot-wide mirror Hale telescope on Mt Palomar in Southern California, gravity grounded dreams of bigger ones for decades. Gradually distorting large pieces of suspended glass, it throws bigger mirrors out of focus. The Keck telescopes, built in 1991 and 1996, overcame that hurdle. Instead of one big piece of glass for the primary mirror they use 36 interlocking, individually suspended hexagonal segments each 6 feet across, with a common focus. Result: telescopes twice as large and as sharp as the Hale and over 3 times as big as Lick Observatory's 10-foot Shane reflector. In theory a much larger telescope could use more segments. The Keck telescopes prove segmented-mirror scopes work well, offering confidence of larger scopes. The OWL telescope would have over 2,000 7 1/2 ft segments.

Atmospheric distortion makes stars twinkle, pleasing poets and annoying astronomers, robbung telescopes of their full potential for clarity. Observatories at high altitude where air is thinner minimize this distortion. This motivated launching the $1.5 billion Hubble Space Telescope with its 8-ft mirror in 1990. Orbiting above Earth, it's freed from atmospheric and gravitational effects plaguing ground telescopes. After Hubble the next generation space telescope with a 26-ft mirror would orbit beyond the moon. Even more far-out designs are possible in space.

While Hubble was built like reflector telescopes on the ground, designs are envisioned with separately orbiting parts miles apart, made of lightweight aluminum and plastic membranes. Such a design could greatly lower one of the biggest barriers to building space scopes: cost, 100 times that of similar telescopes on the ground. Taking advantage of space is to design for space, not take a ground design and figure out how to get it up there. Putting telescopes with a 26-ft or even a 328-ft mirror in orbit exploit the lack of gravity and wind, looking at concepts completely different from those on the ground. Some aren't convinced space-based telescopes are the way to go. It's significantly less expensive on the ground without astronomical launch, update and repair fees. One way to enlarge ground telescopes hooks several together. The Keck scopes were designed for use in tandem. The European Southern Observatory has 2 of its 4 26 1/2-ft telescopes at La Serena, Chile, working together, planning to operate them in unison. Drawback: gathering less light than one big scope.

To that end Japan's telescope Subaru debuted at Mauna Kea with a 1-piece, 27-ft primary mirror. 7 inches thick, it corrects gravity-caused distortions with 264 motors adjusting its shape to compensate. At $400 million - several times the $77 million of the second Keck scope, which is larger - that approach may not be feasible for larger designs. The $13 million Hobby-Eberly telescope at McDonald Observatory in Texas has a 36-ft mirror built with a spherical curve, its 91 identical segments set in a low-cost, fixed-angle mount. Tucson's National Optical Astronomy Observatories consider a larger version. Its drawback is spherical mirrors limit field of view. Its mirror's 30-foot effective area is why astronomers look to expand Keck's design instead. A newly developed computerized system could neutralize atmospheric blur and produce images as sharp as those from space.

Adaptive optics was first envisioned in the 1950s. Computer technology was too primitive to make it a reality. It was revived in the 1980s as secret Star Wars technology and employed more recently to sharpen lasers' focus. National Science Foundation, involving Lawrence Livermore and 8 other universities, fund UC-Santa Cruz' center for adaptive optics. Adaptive optics in Lick Observatory's telescopes made their big-telescope debut at Keck. Using a system developed at Lawrence Livermore, Keck's image is passed to a 6-inch, flexible mirror whose 349 pencil-like arms make hundreds of slight adjustments each second to correct atmospheric blur. Such technology is crucial to reaping the full potential of larger telescopes, from a 100-ft mirror to the $1 billion OWL, 3 times as large. Technology doesn't exist for adaptive optics in telescopes bigger than the Kecks. It would require thousands of tiny correcting arms, not just hundreds. Technical hurdles are a good reason to work on more modest proposals. Adaptive optics technology for such a telescope will be ready when telescopes are. Building a giant On planned completion in 2016, the Giant Magellan Telescope will be four times as powerful as any telescope now on Earth, provided the project can overcome construction and funding hurdles. By Dennis Overbye New York Times TUCSON, Ariz. - In the cavernous bowels of the University of Arizona's football stadium, Roger Angel's mirror furnace was spinning like a captured flying saucer at a stately five revolutions per minute. It was a contrivance that Monty Python or Doc Ock might have designed -- 30 feet across and 10 feet high, covered with red boxes, steel beams, black cables, flashing lights and metal air ducts snaking from its body like octopus arms. An orange glow, from 18 tons of molten glass heated to 2,100 degrees Fahrenheit, was peeking through openings around the ducts as they flashed by. That glass was on its way to being part of the heart of what could be the largest telescope in the world 10 years from now. And so, nearby, several dozen sweltering astronomers and other dignitaries were roaming catwalks, wandering among giant mirrors and mirror polishing machines and swigging bottled water while they kept a weather eye on monitors showing what was going on inside the furnace. One camera was focused on a set of marks on the furnace wall used to gauge the level of the molten glass inside. The level had been falling in the last day as the temperature ramped up and chunks of glass the size of cobblestones softened and began to flow down into narrow channels forming a honeycomb pattern. The glass would stop falling when it had completely filled the honeycomb structure. Meanwhile, centrifugal force would have whipped the overflow into a perfect parabola 28 feet across -- the desired shape for sweeping up starlight dispersed into foggy invisibility over billions of light-years and compressing it into crisp bright dots astronomers could read like a newspaper to learn what was happening around a distant sun or when the universe was born. That was the moment the real work could begin. ``This project is very gutsy,'' said Angel, a slender, gray-haired astronomer who runs the Steward Observatory Mirror Laboratory. He has been building mirrors and populating mountaintops with telescopes this way for 20 years, but nobody has ever built something like this. If everything works out, the mirror now forming in Angel's saucerlike furnace will be only the first of seven making up a giant telescope with the light-gathering power of a mirror 70 feet across. The Giant Magellan, as it is called, would be twice the size of anything now operating on Earth or in space, and four times as powerful. But there are many challenges. To blend their light at a common focus, Angel explained, all seven mirrors will have to be part of the same giant parabola. That means that all of them except the central mirror must have an unusual ``wickedly curved'' asymmetrical shape. And there is the cost. The Giant Magellan will cost half a billion dollars -- money that its collaborators, a consortium of eight institutions, does not yet have. To show that they can make such a mirror, and perhaps shake loose some of that half billion, the collaborators -- which include the Carnegie Institution of Washington; Harvard; the Massachusetts Institute of Technology; the Smithsonian Astrophysical Observatory; the universities of Arizona, Michigan and Texas; and Texas A&M -- announced this year that they would go ahead and make one, at a cost of $17 million, and they invited everyone to watch. ``Everybody in collaboration believes we need to test this technology,'' said Wendy Freedman, director of the Carnegie Observatories and chairwoman of the Giant Magellan board, adding that if the test fails the project will not proceed. Freedman added that they had to start making mirrors now, money or not, to meet their goal of beginning limited operations in Chile in 2013 and finish in 2016. Making that date will allow them to overlap with NASA's James Webb Space Telescope -- scheduled for a 2011 launching -- and keep pace with their rivals, a consortium including the California Institute of Technology, the University of California and the Canadian Astronomical Association, which want to build a telescope 100 feet in diameter, using a radically different technology. The result in late July was a weekend rendezvous in the desert, part fundraising party, part seminar on telescope making and part family reunion. Many participants had worked together on other projects, like Magellan, the new telescope's namesake, which consists of twin 21-foot-diameter telescopes at Las Campanas, a Carnegie observatory in Chile, and the Large Binocular Telescope being built on Mount Graham in Arizona. Angel said part of the pleasure of the Giant Magellan project was working with old friends who could talk in shorthand. In the mirror lab's air-conditioned conference room, Stephen Shectman from Carnegie said: ``I've been coming here for 26 years. I thought I was done. But now we're just starting again.'' Ever since Galileo's time, astronomers have made telescope mirrors and lenses by grinding flat disks of glass together. But such rubbing produces a spherically shaped mirror that must then be reshaped into a shallower curve known as a parabola -- a delicate and error-prone process that has been the bane of many amateur and even professional astronomers. It was during the testing phase of this part of the process, for example, that the builders of the Hubble Space Telescope stumbled, necessitating a dramatic series of spacewalks in 1993 to fit the orbiting telescope with corrective lenses. Moreover, as mirrors have gotten bigger, the traditional method wastes a lot of glass and time. Angel estimated that about 20 tons of glass would have to be scooped out to make the new mirror. ``That's a lot of glass at $40 a kilogram,'' he said. Astronomers and physicists have long known, however, that the surface of a spinning liquid will form a parabola. Indeed, telescopes have been built using spinning pools of mercury as a mirror. The present project grew out of the success of the Magellans, built by Carnegie, Harvard, Arizona, MIT and Michigan, and completed in 2002. The Magellan astronomers are proud of the quality of the images from these telescopes, which they attribute to the smoothness of the mirrors and the stability of the atmosphere at Las Campanas, where the Giant Magellan would be built. Astronomers say the Giant Magellan, augmented with so-called adaptive optics that reduce the blurring from the atmosphere, would be an invaluable tool, among other things, for hunting and studying planets around other stars. It could be years before the Giant Magellan group will know if their gamble has paid off. The mirror is scheduled to cool until late October, when technicians will pop the lid off the flying saucer oven and lift the new mirror out. Only then will begin the arduous task of polishing and testing it. And if after all this they don't get the money for the rest of the telescope? ``We didn't spend time on Plan B,'' Angel said.