The Perfect Machine

by Ronald Florence

  Little did anyone imagine that it would be eleven years before those doors opened again.

  22

  On the Roll

  The safe arrival of the disk put the telescope project in high gear.

  Crews had worked all winter on the mountain, clearing the site and laying pipes for the water supply. Hale’s original plan was to build the entire observatory, except for a small pumping plant and some wooden cottages for observers and caretakers, in a single building. As the plans proceeded, it soon became obvious that they would need far more facilities, from a separate machine shop and utility building to housing for the large work crews.

  Not only was Colonel Brett a martinet, but he ran the workers’ mess hall at a profit and served a horrible meal once a week so the men would appreciate the rest of the meals they got. Whether the situation was routine or an emergency, the colonel liked precise procedures. When a carpenter suffered a heart attack while making concrete forms, the colonel lined everyone up for a lecture on procedures and responsibilities before sending the thirty-five-horsepower Caterpillar tractor down the road to clear a way for the doctor and ambulance to get through two feet of new snow that had begun to turn to ice. Ignoring the colonel’s orders, two men raced down on the Caterpillar, smashed the county gate that had been left locked, and pulled the ambulance up the road to the colonel’s cottage. They were too late. The worker died. In the morning, they had to clear rockslides off the road to get the ambulance back down the mountain.

  Despite the isolation, celebrities were brought up the mountain to see the early work. Herbert Hoover, only a few years out of the presidency, visited Caltech in Pasadena and was brought to Palomar, where he stayed over in Colonel Brett’s house. Sandy McDowell’s wife came along to supervise the dinner preparations for the former president and to hide the colonel’s whiskey bottle of “salad dressing.”

  In the spring McDowell hired a Caltech graduate engineer named Byron Hill to supervise the construction work on the mountain. Hill had been working for the Metropolitan Water District in Banning, California, as a concrete specialist. He was young, confident, and energetic. They agreed to pay him the respectable salary of three hundred dollars per month, plus an unfurnished cottage with heating equipment and hot water.

  Colonel Brett, wearing his uniform and tall boots, greeted the new man outside his cottage. Byron Hill had brought his collie, Mike, with him. Mike sniffed the colonel’s boots, found them satisfactory, and lifted his leg. The colonel kept a straight face, but he and Byron Hill never got along.

  By then Pasadena was generating reams of plans. Engineering students and draftsmen were given sketches and told to produce working plans. The Caltech students who drew up the plans for the utilities on the mountain were precise and careful draftsmen; they drew the power and water lines straight and true. When crews went out to dig, they would find solid rock where the lines were supposed to go. Byron Hill knew engineering professors at Caltech and realized that they were sometimes astonished when engineers in the field, or even their own children, could make the leap from drawings to working models and machines.

  Crews of Caltech students came up for the summer to dig the footings of the dome and the telescope. Beneath the acidic topsoil they discovered decomposed granite, which had to be blasted and hauled away to get down to bedrock solid enough for the foundations. The only heavy equipment on the mountain was the ancient Caterpillar tractor and a fifty-year-old air compressor. Much of the work was done by hand with wheelbarrows, two-wheeled concrete buggies, and hand winches. In the middle of the circle of dome excavations were separate excavations for the piers to anchor the telescope. To reach bedrock for the piers, they had to dig twenty-two feet. A Caltech student with limited blasting experience, a cavalier attitude toward insurance company regulations, and a gung-ho attitude set the charges to blast the boulders out of the decomposed granite.

  Each step of the early construction was a negotiation between the site realities and the plans that came up from the drafting tables at Caltech. The huge one-million-gallon water tank and water tower had been planned to provide water for the concrete work. But filling the caissons with solid concrete would have required a daily fleet of trucks making the rough climb up the steep, winding Nate Harrison Grade, a dirt road that was impassable during much of the winter and spring. Instead Byron Hill framed the caisson excavations with wooden forms, filled the bottom and eight to ten inches of the outside edges with concrete, dumped decomposed granite inside, then poured concrete over the top. They could draw what they wanted at Caltech. Byron Hill knew concrete.

  Hill took over the mountaintop like a whirlwind. In his rakish leather jacket and aviator sunglasses, with the cockiness of a recent Caltech graduate, he leapt into the work, pushing the students and workers, revising plans, improvising when equipment broke down or wasn’t available. The concrete was mixed in a one-cubic-yard mixer, and poured by hand from two-wheeled concrete buggies. The students who did much of the work made a game out of it, racing across the site in timed runs. At the peak of the concrete pouring that summer, every person on the mountain, even the cooks, was called to help with the buggies. Colonel Brett, though nominally in charge, chafed at the pace and Hill’s nonmilitary style. When they began fighting openly, Brett was called to Pasadena for discussions. The story told on the mountain afterward was that the colonel was given fifteen minutes to resign.

  The Caltech students came and went. The men working on the mountain, a small band that had wintered over in the old barracks of the cattle ranch, turned into a cohesive group. They called themselves “zombies” and on Saturdays trooped down to Captain Bolin’s store halfway down the mountain where they would buy Don Leon wine. Byron Hill, in charge after Colonel Brett’s resignation, took a dim view of drinking and carousing but realized that in the isolated conditions allowing some partying was the only way to hold on to good workers.

  To supplement the weekly mailbags from Pasadena, McDowell authorized a radiotelephone. Ben Traxler got a Class I license to operate the unit. A red button on the transmitter at Palomar would bring up the carrier and ring a bell in Pasadena, letting Hill make his reports and requests. McDowell took the calls himself in Pasadena. He liked to acknowledge each statement to show he was on top of every matter. His barked “Yup” would trigger the voice-operated transmitter in Pasadena, cutting off Hill in midsentence. The interruptions, together with the ignition noise on California Street in Pasadena, ensured that Pasadena heard little of what was reported from Palomar. Hill, content to carry on with as little interference as possible, welcomed the arrangement. He could later claim that he had reported his plans before he went ahead.

  By the end of the first year of work on the mountain, cottages had been built for Hill and a few others with families. Mary Marshall became the schoolteacher. Her husband, Harley Marshall, kept account books and arranged public relations for the tourists who were already finding their way up the mountain to see the world’s largest telescope.

  Beyond the bare site for the two-hundred-inch telescope, workmen were well along on the construction of a smaller dome. Inside, workers from the Santa Barbara Street optics laboratory of the Mount Wilson Observatory and machinists from the astrophysics machine shop at Caltech were putting together a telescope unlike any the world had ever seen.

  Bigger telescopes, like the two-hundred-inch, let astronomers see farther into space. For Hubble and Humason, a bigger telescope would let them measure the red shifts of ever-more-distant spiral galaxies, building more evidence for the cosmologists. The big telescopes bit off a tiny portion of the heavens with each exposure or spectrograph, probing deep into one small area of the sky. But even as they designed and built ever-bigger telescopes that could probe ever deeper into the unknown, astronomers dreamed of another sort of instrument, a camera that would allow them to photograph huge segments of the heavens in a single exposure. A camera that could photograph a relatively large swath of the sky, recording celestial objects down to v
ery dim magnitudes, would serve as a “finder” scope for the big instrument, exploring promising areas of the heavens and producing plates that would let the astronomer identify targets for study with the big telescopes. The survey camera could also search for new and rare celestial objects, covering areas of the heavens in a few dozen plates that might take a lifetime to explore with the narrow field of view of the larger telescope. When Hubble began his search for novas in the Andromeda galaxy with the one-hundred-inch telescope—a search that ultimately led to the identification of Cepheid variables and the end of the “island universe” debate—he had to confine his research to three promising areas of the galaxy, because the field of vision of the one-hundred-inch telescope could not take in the entire Andromeda Nebula.

  The problem of building a wild-field camera had stumped opticians and astronomers for years. The mirror of a fast, widefield camera must be steeply curved. But with traditional paraboloid mirrors, the more steeply curved the mirror, the smaller the area of sharp focus in the center of the field of view. The area around the edges is distorted with coma, so the stars look like teardrops instead of sharp points.

  In 1929 Walter Baade was sent on an expedition, with an optician named Bernhard Schmidt, to photograph an eclipse of the sun from the Philippine Islands. Schmidt had lost one arm playing with a pipe bomb of his own design at the age of eleven, and had later eked out a living and money for brandy by polishing telescope mirrors for amateur astronomers in an abandoned bowling alley. He was finally hired by the Hamburg Observatory as their optician. Single, an Estonian by birth, a pacifist by conviction, and eccentric enough in his habits and politics to attract police attention, Schmidt worked alone in his basement workshop, dressing in a cutaway coat and striped pants to grind and polish mirrors and lenses with his one good hand.

  On the ship on their way back from the Philippines, Schmidt casually announced to Baade that he had an idea for a telescope that would photograph enormous areas of the sky with a single exposure, with pinpoint images from edge to edge. The idea, he said, was to use a deep, spherical mirror. Spherical mirrors are relatively easy to shape—the first step in the shaping of a telescope mirror is to bring the surface to a spherical figure—but Baade knew that spherical mirrors smear the light of distant objects, distorting the images. The answer, explained Schmidt, was to put a thin correcting glass in front of the mirror. The ripples in the surface of the correcting lens would be so subtle that they would be invisible to the naked eye, but they would be sufficient to correct the aberrations of the spherical mirror. Baade agreed that the idea was fantastic. If Schmidt could do it, the telescope would be phenomenally useful. But how would anyone grind such subtle shapes into a glass plate?

  Back in Hamburg, Schmidt procrastinated. When Baade and the director of the observatory pressured him, Schmidt said he wasn’t ready. He needed time. He finally asked Baade for some physics handbooks, put on his cutaway jacket, and retreated to his basement vault. He worked for forty-eight hours, taking only cigars and brandy as nourishment, to create a thin fourteen-inch-diameter disk of glass. His method was elegantly simple. He sealed the disk on top of a pot and drew down a vacuum inside the pot, distorting the surface of the thin disk while he polished it flat. When he released the vacuum he had the shape he needed.

  Schmidt and Baade tested the new camera by photographing the Neuer Friedhof, miles away, from a window of the observatory. The photograph recorded the names on the tombstones and the fine edges of leaves of the trees in the cemetery.

  In 1931, when Baade was offered a job at the Mount Wilson Observatory, he brought along a print of the photograph he and Schmidt had taken of the cemetery. John Anderson was impressed. Just when “it is said that there is nothing new under the sun,” Anderson reported to Hale, Baade had brought an idea from Germany “which comes pretty near being new…. The trick is to use a spherical mirror. In a plane roughly parallel to the mirror surface, but passing through the center of curvature, is placed a thin sheet of glass—really a very weak negative lens so figured that it distorts the incoming parallel light just enough to correct the spherical aberration of the mirror.”

  It hadn’t been requested in the original grant from the IEB, but Anderson and Hale agreed that a Schmidt camera, with its wide view, would be a perfect complement to the two-hundred-inch telescope. Russell Porter began working on a design. There was already a pressing need for the new camera.

  In 1934 Fritz Zwicky and Walter Baade began to collaborate. They had discovered that some stars could explode with extreme violence, and coined the name supernova to describe the phenomenon. Supernovas were so rare—the last one in the Milky Way was at the time of Tycho Brahe—that Baade and Zwicky were forced to study the remnants of the few supernovas that had been seen by naked-eye observers, like the Crab Nebula. Zwicky wanted a widefield Schmidt camera to search for supernovas. When he asked George Hale to allocate money for the camera, Hale said it sounded like prospecting for gold but approved the funds. While Porter was working on the design, Zwicky wandered into his office, made some suggestions, and before long was telling everyone that Bernhard Schmidt had shown him the photographs of inscriptions on the gravestones on a visit in 1935, and that the idea of building a Schmidt camera was actually his.

  Opticians at the Mount Wilson optical labs figured the twenty-four-inch mirror and eighteen-inch correcting plate for the new Schmidt camera. The Caltech astrophysics machine shop built the tube and mounting. Russell Porter’s design looked like an eighteenth-century cannon mounted in a tuning fork. The correcting plate was at the muzzle of the cannon, protected by shutters that opened and closed to control the exposure of the film. The film holder inside the camera was reached through a door in the side. The machine shop built film holders that would cut the photographic emulsions in a circle and bend the emulsions so their curvature exactly matched the spherical focal curve of the camera.

  As the eighteen-foot-diameter dome went up at Palomar, experienced Mount Wilson workmen came up to install the new telescope. Jerry Dowd, the master electrician from Mount Wilson who had wired the electric controls for the solar telescope in George Hale’s laboratory, did the wiring. Dowd had retired from the observatory to a ranch, until he heard about the new work going on at Palomar. He couldn’t resist the opportunity to wire another telescope, even though he was only paid the same sixty-seven and a half cents per hour that the regular construction workers received. Ben Traxler got the job of helping the mechanics and technicians from Pasadena do the installation and learned the tricks of slip-couplings for the rotating dome and the complexities of wiring for telescopes.

  By the fall of 1936, the Schmidt camera was in operation. One of the cottages on the mountain had been rushed to completion for Zwicky’s use, and he began making the trip from Pasadena to Palomar to photograph galaxies, searching for supernovae. Byron Hill met Zwicky on one of his first trips up the mountain, in a heavy snow. Hill had sent the Caterpillar tractor with a chain to pull Zwicky’s car. Zwicky wanted rope instead of the chain, and before long they were in a full-scale argument. To Zwicky, Hill was one more “spherical bastard”—no matter which way you looked at him, he was still a bastard. The astrophysicist recruited Ben Traxler as his night assistant on the telescope, and soon Zwicky would signal his arrival on the mountain each night with a shout of “Wo ist Traxler?” That slight of protocol, circumventing Hill’s authority as superintendent on the mountain, didn’t sit well with Hill. The politics of the mountain began early.

  Zwicky, in his first films of galaxies in Virgo, found supernovas. He kept up the search, pushing and tugging at the sometimes balky Schmidt camera until its battleship-gray tube was dented with scars. Zwicky still holds the record for the most supernovas recorded by a single observer.

  In Pasadena the arrival of the disk, coupled with Sandy McDowell’s eagerness to begin the actual construction, put the final stages of the design of the telescope in high gear.

  Once the yoke mounting, with a giant horsesh
oe bearing to support the weight at the north end of the telescope, had been selected, the pieces of the design began to fall into place. Mark Serrurier, who had been given the challenge of designing the tube of the telescope, had fiddled with his pencils until he stumbled on an idea so elegant and simple that engineers who looked at his drawings shrugged and asked, “Why didn’t I think of that?”

  Serrurier knew that the weight of the mirror in its cell at one end of the tube and the prime focus cage, with equipment and auxiliary mirrors, at the other end of the tube, made it fundamentally impossible to design a telescope tube that wouldn’t flex. He kept playing with Martel’s suggestion that the tube didn’t have to be absolutely rigid, that what mattered was for the primary mirror at one end of the tube, and the correcting lens or auxiliary mirror at the other, to be perfectly aligned with each other. If both ends of the fifty-seven-foot-long tube drooped, even as much as one-sixteenth of an inch (an enormous distance at optical tolerances), it would not affect the alignment of the mirror and the prime focus as long as both ends drooped the same amount and remained parallel to each other.

  Suddenly the problem was much simpler. Serrurier sketched supports that ran diagonally from the corners of the tube to its central pivot point. Compared to the massive braced girders that had been used for previous telescopes, the supports seemed airy. But the diagonal supports meant that any motion of the ends of the tube would create compression in the supports. Try to compress a rod, as opposed to bending it, and the effect of Serrurier’s structure is immediately clear. The ends of his tube would droop by a millimeter or so, but the diagonal struts would keep the two ends parallel and perfectly aligned. The elegant, symmetrical structure immediately earned the name Serrurier truss. In various forms it was soon widely copied for telescopes and other structures.