When he returned to the United States, he went into partial seclusion at his home in Pasadena, to carry on his own researches into the sun. He built a private solar laboratory on a piece of land that had once been part of the original grounds of the Henry Huntington estate, and equipped the building with mirrors. The building’s doorway was of carved wood and stone, arched over with hieroglyphs and an image of the rayed sun, copied from a tomb at Thebes; and the building had an underground room where Hale brought a shaft of sunlight into his instruments, and where he hoped to spend the rest of his days. But he could not keep his mind from a mirror, around which his imagination had been turning since the end of the Great War. Hale had not severed his contacts with friends and colleagues, nor with the Mount Wilson Observatory. He took the oxymoronic title of Director Emeritus, which suggests that some kind of force-field emanated threads of energy from his solar laboratory across the city of Pasadena to the headquarters of the Mount Wilson Observatory on Santa Barbara Street. In fact Hale continued to be a strong influence there during the early 1930s. Hale, in turn, may have been under the influence of the elf. Helen Wright, Hale’s biographer, learned about the elf from a certain Dr. Leland Hunnicutt, who was a friend of Hale and who had listened sympathetically to Hale’s descriptions of the elf. Wright does not say exactly what kind of advice this elf was giving to Hale, although she says that the elf “became almost a mascot.” For all we know, the elf may have had in mind a two-hundred-inch telescope, which raises the possibility that one of the great scientific instruments of the twentieth century may have been built partly on the advice of an elf.
When Hale felt well enough to face the rigors of contact with humans, he received visitors in the library of his solar laboratory. There, stabilized in an armchair that had a book rest and a writing table attached to it, beside a fireplace that displayed a bas-relief of Aten riding his chariot into the sun, Hale talked and wrote about a giant mirror until he gave everyone the whirligus. At that time the one-hundred-inch Hooker Telescope on Mount Wilson was the world’s largest. Hale pointed out that a mirror two hundred inches in diameter would have four times the surface area of a hundred-inch mirror; four times the light-gathering power. “Starlight is falling on every square mile of the earth’s surface, and the best we can do at present is to gather up and concentrate the rays that strike an area one hundred inches in diameter,” he wrote in 1928, in an article for Harper’s magazine. These words struck a chord with the board of trustees of the Rockefeller Foundation, which after consulting with John D. Rockefeller, Jr., decided to provide funds for Hale to build a two-hundred-inch telescope.
Hale naturally wanted the money to go to the Mount Wilson Observatory. But the Mount Wilson Observatory was funded by the Carnegie Institution of Washington, which had been endowed by Andrew Carnegie. The Rockefeller trustees did not like the idea of giving Rockefeller money to a Carnegie observatory. The resulting negotiations nearly pitched Hale into bed, but he managed to work out a compromise. The Rockefeller Foundation gave six million dollars to the California Institute of Technology, in Pasadena, while at the same time Hale secured an agreement between the California Institute and the Mount Wilson Observatory to cooperate with each other in the building and operation of the telescope.
When the money had been pledged, Hale established various committees to plan the telescope. John Anderson, a Mount Wilson astronomer, was appointed executive officer of the project. Various sites on mountains throughout southern California were tested for dark skies and good seeing. “Seeing” refers to turbulence in the atmosphere. Viewed through a large telescope, stars appear to waver and tremble, as if they were near a radiator. Poor seeing causes stars to twinkle. Hale wanted to find a mountain where the stars did not twinkle. In the spring of 1934, Hale and Anderson drove up Palomar Mountain in a Pierce Arrow touring car, along a winding dirt road. (Two years earlier, on the occasion of Albert Einstein’s first visit to Pasadena, the Mount Wilson Observatory had blown a small fortune on this automobile, in order to put Einstein in a luxury car.) Hale and Anderson went from one end of the long mountain to the other, comparing sites for the telescope, until they chose a fern meadow at an altitude of 5,600 feet. The meadow was accessible, yet far from city lights, and something about the meadow’s topography muted the air above it, calming the stars into points during many nights of the year. The site had water too—a ravine opened to the north, where Horse Thief Spring trickled from beneath oaks that had been growing a century before Isaac Newton was born. The San Luiseño Indians had called the place Poharup—Noise of Falling Water.
The major responsibility for designing the telescope went to John Anderson and a committee of astronomers and engineers. They tested and discarded a number of designs for the tube and mounting of the telescope before they hit upon what is now known as a yoke-and-horseshoe mounting. The telescope’s tube swings between the arms of a fork, which resemble the arms of a tuning fork and are called a yoke. As the tube tracks the stars from east to west, the tuning fork rotates around its handle; the arms of the yoke turn. The tube of the telescope weighs heavily upon the yoke, and so the ends of the yoke rest for support on a gigantic horseshoe bearing—a lazy C, which slides on its back, floating on a layer of Flying Horse telescope oil. The tube is a scaffold made of I-beams, fifty-five feet long, designed by a structural engineer named Mark Serrurier. Serrurier’s design is called the Serrurier Truss. The truss flexes under strain, as does a bridge. Both ends of the tube are free to sag by up to a quarter of an inch, and yet the tube holds the two principal mirrors—the sixteen-foot primary mirror and the four-foot secondary mirror at the top of the telescope—in perfect parallel alignment to within a hundredth of an inch, no matter where the telescope points, and thus keeps the stars in focus. “I was given a job nobody thought could be done,” Mark Serrurier told me. “That’s where I got my satisfaction.”
During the summer of 1936, work crews blasted and dug a circle of holes in the fern meadow. Caltech students hauled rock out of the holes by hand, using wheelbarrows. The dome was designed by committee. Russell Porter, an artist, explorer, and amateur telescope maker, may have elaborated some of the Art Deco decoration on the dome, although even these details seem to have been worked out by the committee. Porter noticed that the dome’s size was within two feet of the diameter and height of the Pantheon in Rome. The committee had evidently not planned that.
The Westinghouse Electric and Manufacturing Company, in South Philadelphia, cast and machined the tube, the yoke, and the horseshoe bearing. A workman named William Ladley put the last rivet into the Serrurier Truss, before a crowd of dignitaries in South Philadelphia, including Albert Einstein. Tube, yoke, and horseshoe bearing traveled to California through the Panama Canal, chained to the deck of a freighter. Those parts were assembled on the mountain, inside the dome, under the direction of a master engineer named Byron Hill, who later became the observatory superintendent. I found Byron Hill in a double-sized mobile home on top of a hill in Tuolumne, California, with his wife, who was in poor health. He spends his mornings feeding birds on the patio and drinking coffee, and does not spend a lot of time congratulating himself on what he did to improve the vision of the species. “I get a little older every day,” Byron Hill said. “I object to it.” During his days as superintendent of the observatory, the astronomers sometimes referred to Palomar Mountain as Byron’s Hill. They regarded him as a tough customer; he used to wear a leather jacket and aviator’s glasses. He once threw an astronomer out of the dining room for wearing Bermuda shorts—“His legs shocked the housekeeper,” he explained to me. On another occasion a night assistant parked his truck inside the Hale dome, where Byron thought it did not belong. Byron fitted a chain around the truck, hoisted the truck up to the top of the dome, and let it dangle next to the Hale Telescope. About the tube, yoke, and horseshoe bearing he said, “The things fitted together beautifully.”
The mirror-blank was cast at Corning Glass Works, in Corning, New York. George McCa
uley, a master of Pyrex, directed the work. McCauley was a taciturn man. Asked how he planned to cast the glass, he said, “It will be no different than making a bean pot, except in the methods employed.” The methods included building an igloo-shaped oven and casting a series of disks inside the igloo, in molds that resembled waffle irons. McCauley started with small disks and worked his way up to two hundred inches. His methods produced a mess during the first casting of a two-hundred-inch disk, when pieces of the mold broke off and floated away in a mulligatawny of hot Pyrex. Asked what he planned to do next, McCauley snapped, “We’ll just make a new disk.” On December 2, 1934, McCauley’s men ladled about forty buckets of white-hot Pyrex into another waffle mold. The Pyrex was thick stuff and oozed out of the buckets in glops, like refrigerated honey. McCauley kept the melt in the oven for ten months, gradually cooling it, letting the glass anneal.
When McCauley opened the cold oven, he saw that he had made the world’s largest monolithic piece of glass. It had a hole in the center, like a doughnut. Corning engineers encased the disk in a steel shell and stood it upright on a flatcar, to be drawn by a steam locomotive to California. For more than two weeks the telescope train crossed the United States, often at speeds of five miles an hour. Every time the train stopped, armed guards dived underneath it, looking for hobos trying to ride under the disk, for this was the Depression. Huge crowds turned out. Ten thousand people in Indianapolis watched the telescope train pass. Afraid that someone might try to take a potshot at the disk, Hale and Anderson felt it necessary to armor the disk with steel plates. If a bullet had broken the glass, that certainly would have killed Hale. At night the train was parked on a siding, illuminated with floodlamps, and patrolled by guards carrying loaded rifles, who had orders to let nobody approach within shooting distance. The train passed through St. Louis, Kansas City, Clovis, Needles, and San Bernardino, and arrived in Pasadena on Good Friday, April 10, 1936, witnessed by crowds. The disk was unloaded and lifted into the Caltech optical shop. A Pasadena newspaper reported: “There has not been such excitement since Ambler’s Feed Mill burned.”
The excitement was too much for George Ellery Hale. Too ill, physically and psychologically, to watch the triumphal entry of his glass into Pasadena, he had withdrawn from the world, broken on the wheel of whirligus. He spent his last years with his instruments in the underground chamber of his solar laboratory, looking into the sun. Day by day a heliostat mirror (a sun-tracker) turned slowly at the top of the building, throwing a shaft of sunlight into the basement, where Hale, staring through an eyepiece just two millimeters across, watched prominences heaving and lapsing around a ball of hydrogen as old as the world but never the same from one minute to the next. His grandchildren would visit him and listen to his stories, and perhaps the elf listened too. He maintained contact with the Palomar project through long letters to a few friends. In 1938, at the Las Encinas sanatorium in Pasadena, he said to his daughter, Margaret Hale, “It is a beautiful day. The sun is shining, and they are working on Palomar.” He died a few days later. Hale had not returned to Palomar Mountain since the day he chose the fern meadow. He never saw his greatest telescope.
Marcus Brown, Caltech’s chief optician, directed the grinding of the mirror. Brown hired twenty-one unemployed men (mostly right off the street) to operate a polishing machine. Brown’s men wore white suits and white sneakers—clothing that never left the shop. The glass disk sat on a turntable. While the turntable rotated, an arm pressed a rotating circular polishing tool against the glass; the arm moved the tool in differing directions across the glass, thus tracing overlapping cycles of movement known as Lissajous figures.
I drove up into the Verdugo Hills, near Pasadena, one afternoon in spring, along an unmarked dirt road, until I found a sunny house where lived Melvin Johnson, who as far as I could tell was the only master optician still alive who had worked on the two-hundred-inch mirror. We sat and drank coffee, and Johnson said that it had been so long since he had talked about that mirror that he might have a little trouble finding the right words, but then his words began to move in Lissajous figures around a giant disk of flame Pyrex with a hole in the middle. The opticians inserted a Pyrex plug into the hole before they started to polish the disk. The polishing tool was covered with a layer of black pitch, which rubbed and sleeked against the glass. The formula for the pitch changed now and then, Mel Johnson said, and the method of cooking the pitch in a pot was essentially a black art. “We tested all kinds of mixtures. I threw out a garbage can full of formulas,” he said. The pitch, he said, contained amber rosin from Alabama pines, pine-tar oil, and beeswax. Hoping to get a smoother polishing action on the glass, the opticians experimented with pitches adulterated with paraffin wax, automobile motor oil, and a powder made from ground walnut shells, “which was like flour,” Johnson said. Every few minutes the opticians poured across the glass a slurry of water and Carborundum grit. They used finer and finer grades of Carborundum and then switched to red jeweler’s rouge. By 1941, they had polished away five and a quarter tons of glass, had used up thirty-four tons of abrasives and jeweler’s rouge, and had brought the surface of the Pyrex disk down to a hollow sphere. From there they had to deepen the glass slightly into a paraboloid. A paraboloid is a saucer that focuses light to a point. The layer of glass that they had to remove in order to parabolize the mirror equaled the thickness of half a human hair. This work required eight more years of polishing, interrupted by World War II, when Caltech halted work on the telescope.
The opticians were afraid that their machines would drop a metal filing on the glass. A grain of metal or grit trapped between the polishing tool and the glass would have cut a helical scratch in the glass that would have delayed the project for six months, or perhaps for years. They swept the room with vacuums and electromagnets. Then they looked at the dust they had collected under a microscope, classified the particles, and saved them in envelopes. If they saw a dust particle of a type they did not recognize, they stopped all their machines until they could trace the particle to its source. Toward the end of the polishing, the opticians spent more time testing the glass than rubbing it, fearful that they might polish too deeply in places, especially around the outer edge of the glass, in which case they might never be able to resurrect a true optical surface. Their testing apparatus was keen enough so that an optician could place his hand on the glass for a minute until the glass warmed, take his hand off it, and see a swelling in the shape of a hand persist on the glass. Before they looked at the glass through the testing apparatus, they had to turn off all fans and prevent people from walking around the room, “because a current of air coming through the room made the air look like a smoke screen,” Mel Johnson said. He remembered seeing waves twitching along the surface of the glass, as if the glass were restless, gently pulsing with life. The waves mystified the opticians, until they discovered that the mirror was picking up harmonic vibrations from traffic on California Boulevard, near the optical shop. After that the opticians scheduled precision testing of the glass for early Saturday mornings.
When the surface of the glass had reached a fairly acceptable paraboloid, the opticians removed the plug from the hole in the center of the glass. In November 1947, they mounted the glass in a steel mirror cell (it would never leave the mirror cell again) and put it in a box and carried it in a flatbed truck up Palomar Mountain. The purpose of the superstructure of the telescope is to move the glass around and to keep it pointed at one spot in the sky. The purpose of the glass is merely to support five grams of reflective aluminum in a perfect paraboloid, in order to focus starlight into a camera. John Strong, a physicist, had invented a technique for depositing aluminum on glass. Strong had taught the Caltech opticians his trick and then moved on. He eventually wrote a textbook on physics. When I asked around Caltech about John Strong, people seemed to think that he was dead. I made some telephone calls to various parts of the United States and turned up John Strong in Amherst, Massachusetts, nowhere near dead, because h
e was working on a new edition of his textbook. “I never saw the mirror again,” Strong said over the telephone. He explained that he had had to clean the glass in order to make the aluminum atoms stick to it, for he had learned that oil from the human skin, which inevitably got on the glass from the opticians’ hands, caused aluminum to crinkle off. Strong had tried washing astronomical glass with chemical solvents, but no solvent seemed powerful enough to remove skin oil. Then Strong discovered Wildroot Cream for the hair. “I never used it on my own hair,” he said, “but it was one of those things you just knew about.” He mixed powdered chalk with Wildroot Cream and rubbed it all over the two-hundred-inch glass, which terrified the opticians. “In order to get glass clean,” Strong told them, “you first have to get it properly dirty.” He wiped the sludge off with wads of felt, leaving a molecular film of Wildroot Cream on the glass. He placed the glass in a vacuum chamber, then fired hot electrodes over the glass, which burned off the Wildroot Cream along with the fingerprints, leaving virgin glass. “Wildroot Cream was one of those little black arts,” Strong explained to me. “It has Peruvian lanolin in it.” While the glass was still sitting inside the vacuum chamber, Strong vaporized aluminum wires in the chamber, and aluminum fell in a dew over the glass.
The opticians opened the tank; the glass had become a mirror. Three nights before Christmas, 1947, a crowd of astronomers and engineers gathered in the dome for first light. They rolled the mirror cell under the butt of the telescope. They raised a hydraulic jack and inserted the mirror into the telescope. Byron Hill’s workmen began tightening a circle of bolts around the mirror.
A bang and a hideous squeal filled the dome. It sounded like a pig being clubbed to death—the unmistakable screech of a crack fingering through sixteen feet of Pyrex. Many eyes turned toward John Anderson, who had been waiting twenty years for this moment and who had a heart condition. After a silence during which Anderson did not collapse, a workman said, “You ever seen a one-million-dollar bolt snap?” The bolt had not snapped off, anyway; it had only creaked. A few minutes later, John Anderson sat in a lift chair, which raised him fifteen feet until he could peer into an eyepiece mounted at the base of the Big Eye. He gazed for a while into the Milky Way, in silence. When he came down, somebody asked him, “What did you see?”