- About Us
Palomar, After 50 Years
Photos from this article depict the installation and early history of the Palomar Observatory.
In November 1947, a 16-wheel trailer from the Belyea Truck Company carefully backed into an oversized doorway at one end of an odd, windowless building on the campus of the California Institute of Technology in Pasadena, California. Belyea, famed for once moving a ship across the desert, claimed in their advertisements that there was no cargo they couldn't move.
The object waiting inside the building wasn't the largest or heaviest cargo Belyea had ever moved, but with a crate over 17 feet square, and weighing almost 40 tons, it was large enough to require careful maneuvering, including a good deal of manual manipulation with crowbars and slide plates to get the trailer and cargo out of the narrow doorway that had been designed to accommodate this one delivery. Once it was outside, the huge trailer and cargo, parked on California Avenue and surrounded by guards, attracted the attention of local and national reporters. The Caltech public relations office had received suspicious phone calls about the shipment, and were eager to hold down the opportunities for potential troublemakers to interfere with the delivery. They promised the reporters advance notice of the departure in return for their agreement to embargo all news about the shipment until after the tractor and trailer left the campus.
Newspaper readers could remember stories of other famous cargoes. When the U.S. Mint moved to San Francisco, the newspapers ran photographs of the caravans of armored cars, and the reporters exhausted their superlatives describing the value of the specie and currency in the armada. From the insurance policy on the cargo that waited on California Avenue--Caltech had negotiated the premium down to $1,850.00--this cargo hardly rivaled the mint. The only identification on the crate was the banners proclaiming that it was moved by Belyea Trucking Co. and Pacific Crane & Rigging. Yet for those who knew what was in the crate, this was a cargo that would change the world.
The eager reporters waited while Irving Krick, a renowned Caltech meteorologist whose consulting success allowed him to drive a much-envied Cadillac convertible, studied his charts. Krick predicted two clear days starting on Sunday, November 18. After final calls to check weather along the route and at the destination, at 3:15 Sunday morning, the Belyea driver started the big diesel engine of the tractor. Ten Highway Patrolmen on motorcycles took up positions around the tractor and trailer, and amidst a blaze of flash bulbs from the waiting photographers with their Speed Graphics, the driver pulled out onto California Avenue at the majestic speed of five miles per hour.
For the first few miles, a Caltech engineer named Bruce Rule sat on top of the cargo with a portable chart recorder to track the vibrations of the load. On the smooth pavement of Rosemead Boulevard he authorized the Belyea driver to speed up to fifteen miles per hour. Later, on Los Alamitos Boulevard in Norwalk, they dropped back to eight miles an hour. Through the early morning, the stately procession crawled through towns and orange groves. They had been authorized to ignore traffic lights and stop signs. Before each intersection, the lead motorcycles would pull ahead, close off the crossroad, and direct motorists to the sides of the road. Drivers would instinctively protest, until they saw the trailer and crate.
Farmers and workers who had gotten up at first light stood alongside the roads to watch the huge cargo go by. A few asked, "What is it?" Those who had kept up with two decades of newspaper stories quickly answered with the ubiquitous-if-wrong moniker the newspaper reporters had assigned to the most famous piece of glass in the world: They called the huge mirror inside the crate the "The Giant Eye," a phrase pronounced with the reverence usually reserved for war heroes and saints. The Giant Eye had been in the newspapers and on the radio often enough since 1934 that the magic phrase was enough to silence crowds, even in the midst of the morning rush. Some took their hats off. Those who stood by the sides of the roads and watched The Giant Eye go by knew they would have something to tell their children and grandchildren.
The Twenty Year Endeavor
For twenty years, from 1928 to 1948, the building of the 200-inch telescope on Palomar Mountain captured the imaginations of America.1 Never before, and perhaps never again, would such widespread attention be devoted to a scientific instrument with such benign aims. When the grant to build the telescope was announced, in October 1928, Herbert Hoover was running against Al Smith for the presidency, Babe Ruth and the New York Yankees had just won another world series, the Graf Zeppelin had completed its maiden flights across the Atlantic, and Congress had just awarded a special gold medal to Thomas Edison in recognition of his achievements. The nation was self-confident. America had won the war to end all wars. Inventions like the radio promised a new era of technology. The stock market was booming, and Americans were optimistic about a future that seemed without limits. A telescope, huge in its conception, designed to see to the very edges of the universe, to expand mankind's knowledge into the infinite, was the perfect symbol for the boundless confidence of the age.
The initial announcement of the grant was understated. George Hale, the astronomer, philanthropist and administrator of science who had secured the grant from a branch of what would become the Rockefeller Foundation, had a scientist's reservations about publicity. He was careful not to announce the size of the grant, $6 million dollars, by far the largest grant ever awarded in support of a scientific project, lest the publicity draw the attention of hucksters, promoters, and others who would distract and perhaps derail the project. Despite his efforts to keep the project quiet, the announcement attracted immediate attention. GIANT TELESCOPE OF IMMENSE RANGE TO DWARF ALL OTHERS headlined The New York Times. The Los Angeles Times made little effort to conceal their pride that this greatest of all scientific ventures would be announced, managed, and probably sited in Southern California: "The scientific world is frankly a-tiptoe with excitement," they wrote.
Hale had conceived and ultimately secured the grant for the project because by the 1920s, astronomy, and particularly cosmology, seemed on the verge of answering fundamental questions about the size, structure, and origins of the universe. The questions the astronomers were raising were the same questions men and women had asked since the first cavemen stared up at the evening sky. With striking new images and spectra of globular clusters and galaxies (they were still called nebulae at the Mount Wilson observatory) from the big new telescopes on Mount Wilson, and the theoretical underpinnings provided by astrophysicists and physicists, including Albert Einstein, the answers to those questions seemed almost within reach. Hale, with the experience of raising the funds and organizing the design and construction of the 40-inch refractor at Yerkes Observatory and the 60-inch and 100-inch reflectors at Mount Wilson, each in its turn the largest telescope in the world, was convinced that an even larger telescope would be able to reach that much deeper into the far reaches of the universe, enabling astronomers to close in on these age-old questions. In the initial press release for the new project, he urged the newspapers not to write about "inhabitants or other hypothetical creatures" that might be seen on the moon with the telescope and that the purpose of the telescope, was "not to detect skyscrapers on the airless moon or to search for indications of human beings on Mars."
From our vantage point, seventy years later, it is hard to imagine the challenge the undertaking represented. The largest telescope in the world, the 100-inch Hooker telescope on Mount Wilson, had taken over a decade to build; the 100-inch telescope was a remarkable instrument and was successfully used by Edwin Hubble and others for pioneering research in the 1920s, but even a decade after it was put into service, the telescope still had significant problems which Hale and his colleagues quietly kept on Mount Wilson. The engineering, materials, fabrication, and personnel problems of building that telescope had driven George Hale to the edge of madness, with recurring bouts of what the age called nervous exhaustion.
The 200-inch telescope he now proposed would be so much larger--the size of a telescope increases not linearly with the size of the primary mirror, but exponentially--that the materials, design, engineering, instrumentation, and fabrication challenges of the new machine seemed to many insurmountable. It was clear that the plate glass that had traditionally been used for large telescope mirrors would not be suitable for a 200-inch mirror, and there were no alternate materials that had been successfully used for a large mirror. The designs of existing telescopes could not be scaled up to a 200-inch telescope and it wasn't clear that any design could meet the goals of rigidity and precision the telescope required. The Bureau of Standards, the official government authority on questions of science and engineering, had already announced that a telescope mirror that large could not be built. Other critics argued that even if the telescope could be built, there was no site with seeing2 good enough to take advantage of the light-gathering and image resolution of a 200-inch telescope. H.L. Mencken, America's most famous cynic, was fed a steady diet of rumors about the proposed telescope at the Harvard Faculty Club by Harlow Shapley, the Director of the Harvard College Observatory and a one-time observer at Mount Wilson who had become a rival of the California observatories. While Shapley buttonholed astronomers and foundation officials at professional meetings to raise questions about the latest proposal of the California astronomers, Mencken wrote skeptical notices about the project for the popular press.
It was easy to believe the skeptics. The 200-inch telescope was not the first large-scale scientific endeavor in the U.S.--the U.S. Geological Survey had involved enormous funding and vast numbers of people--but the project to build a 200-inch telescope was Big Science of an unprecedented dimension. The huge telescope George Hale proposed would have at its heart a 200-inch diameter mirror, ground and polished to a paraboloid figure within a tolerance of millionths of an inch. The mirror would have to hold its figure3 as the telescope experienced the extremes of temperature in an observatory on a remote mountain top, and as the telescope moved from pointing at the zenith to the horizon. The mechanical structure of the telescope would have to hold a photographic plate in near-perfect alignment fifty feet from the mirror, even as the telescope moved to follow the rotation of the heavens. The control mechanism for this enormous machine would have to compensate for aberrations in the apparent movement of stars and the refraction of the atmosphere. George Hale cautiously estimated but did not publicly admit that it might take as long as six years to complete the project.
The design and construction of this extraordinary machine, Hale and others involved with the project realized early on, would require an unprecedented cooperation between academics, industry, and government. The basic research on materials and the exploration of new engineering and fabrication concepts would require simultaneous research efforts at dozens of institutions, teams of designers and engineers from multiple institutions working together, and machining and other fabrication processes at far flung facilities, many on a scale never before attempted. The management and coordination of these far-flung efforts would require a level of organization orders of magnitude more complex than the loose academic committees or the-buck-stops-here management strategies that had sufficed for earlier telescopes.
Today, the cooperation of government, universities, and private corporations on huge and complex research and construction projects is commonplace; an alphabet soup of agencies--NASA, NSF, DARPA, NIH--exists to facilitate, fund and coordinate cooperative ventures. In 1928, those mechanisms were unknown, and deep-seated suspicions and skepticism divided industry, academia, and government. In 1914, a congressman questioning a witness at an appropriations committee meeting said, "What is a physicist? I was asked on the floor of the house what in the name of common sense a physicist is, and I could not answer." The industrialist Andrew Carnegie funded major scientific institutes, but remained skeptical of formal scientific discourse; he said of the National Academy of Science, "Oh, that's just one of those fancy societies."
The few instances of cooperation between government, academia and industry, like the Sound Laboratory at New London, Connecticut, a joint venture of Columbia University and the U.S. Navy, grew out of the wartime need for research on sonar as a defense against U-boats. Once the wartime synergy yielded to Harding's "Return to Normalcy," the only mechanism available to initiate contacts was the personal friendships and acquaintances, and shared common values that a later generation would call the Old Boy network. Hale began his research efforts for the new telescope at the University Club in New York.
For the first year of the project, while Hale was calling on fellow club members like Elihu Thomson and Gerard Swope of the General Electric Corporation to ask their help with the development of a fused quartz mirror for the telescope, staff members of the Observatory Committee at the California Institute of Technology and the Santa Barbara Street offices of the Mount Wilson Observatory were quietly beginning the exploration of sites for the great telescope, and calling on engineers and astronomers to discuss designs for the mounting, instrumentation, and the myriad other technical and management details of the huge project. Hale and his colleagues knew that the early stages of any project inevitably involved false starts, tentative explorations that reached dead ends, trial balloons that drifted to nowhere. Fortunately, after the initial announcement, there was little immediate publicity about the project. The nation was too busy with other headlines to notice, as again and again the yeasty stock market hit new highs, attracting not only experienced investors but working men and women investing their life savings and funds they didn't have, lest they miss out on what the slang of the day called "the action."
Exactly one year after the announcement of the grant to build the telescope, on a day that would be remembered as Black Tuesday, the stock market collapsed. The immediate impact was on speculators and those who had been lured to invest on margin. But within a year the effects of the collapsing market spread through the American and world economies. A deepening depression replaced the euphoria of only a year before, as the self-confidence of the nation fell with the stock market. Men and women were asked to share jobs, the less fortunate waited in breadlines, and men wearing the threadbare remnants of the suits and overcoats from their days in corporate offices sold apples or pencils in the street to feed their families. George Hale became even more reticent to publicize the telescope project, lest the $6 million grant become a magnet for criticism.
It was during those quiet years of the early Depression that some of the most important decisions about the new telescope would be made. In the changed economic climate of the Depression Hale and his colleagues assumed this was likely to be the last very large telescope for a long time. That put pressure on them not only to make the telescope the very best instrument possible, but also to add features and refinements that had once been only pipedreams of the astronomers. Earlier telescopes had required hours or days to be reconfigured from observing nearby stars to spectroscopy or imaging at the edge of the observable universe. The new telescope would reconfigure itself at the push of a few buttons. Earlier large telescopes, like the 60-inch telescope on Mount Wilson, were notorious for tracking anomalies that required constant attention by the observer, even occasional body language on the telescope mounting. The new telescope would have a control system that would allow the night assistant to dial in the coordinates of a star, push a button, and have the telescope automatically point to the object and track it. A talented young astronomer at the Mount Wilson Observatory, Steven Smith, was given the assignment of designing an analog computer to refine the pointing of the 200-inch telescope, using a complex and unprecedented collection of three-dimensional cams and gears to correct for minute aberrations in the apparent movements of the heavens. Smith lost a race with cancer while he was designing the computer; his designs were later turned over to an engineer recommended by Vannevar Bush.
One major issue was the question of where the telescope should be sited. As the largest telescope in the world, it would be the premier research instrument. Astronomers at the eastern universities were eager that it be located where they would get equal access to the facility. Hale, who had been in the leadership of the establishment of the observatory at Mount Wilson, just outside Pasadena, had different ideas. He felt strongly that a major telescope needed to be sited "within a few hours' ride of such a strong group of investigators as we have in Pasadena." Interpreting the data from the telescopes--usually in the form of images or spectra on glass plates--would require the interpretive input of astrophysicists and physicists from a strong faculty, and the telescope instrumentation would need constant service and upgrades from optics labs. Hale was accustomed to an arrangement like the one for Mount Wilson, which had optical laboratories and equipment for the analysis of plates and spectra at their Santa Barbara Street offices in Pasadena.
Hale also had a site in mind. In 1903, the Carnegie Institution of Washington had commissioned J. W. Hussey of the Lick Observatory to explore possible sites in the United States, Australia, or New Zealand for a "southern and solar observatory." Hale's own research was in solar astronomy, and he eagerly followed Hussey's reports of the superb atmospheric conditions in Southern California. The early movie makers had come to California for the same reason.
One site Hussey visited particularly intrigued Hale, a remote mountain rising above the desert roughly halfway between Los Angeles and San Diego. "Nothing prepares one for the surprise of Palomar," Hussey wrote.
There it stands, a hanging garden above the arid lands. Springs of water burst out of the hillsides and cross the road in rivulets. The road is through forests that a king might covet--oak and cedar and stately fir: A valley where the cattle stand knee deep in grass has on one side a line of hills as desolate as Nevada; on the other side a majestic slope of pines.4
In 1903, Palomar Mountain had been too remote for a telescope. Once a source of timber for missions, by the turn of the century Palomar, within a few days' stage of Los Angeles and San Diego, had become a popular summer resort, with seasonal hotels and a tent city that blossomed each summer in the Doane Valley. The trail that ascended the west shoulder of the mountain, called the "Nigger Grade"5 by locals, took a full day for a team; there were halfway camps for travelers making the ascent. Later, when the automobile and the era of relatively easy travel ended Palomar's days as a resort, a few intrepid souls challenged the hairpin turns and switchbacks in early automobiles. The grade took a toll in gears and overheated engines, and the downhill run usually required tying a tree to the rear bumper as a drag brake. At the bottom of the mountain the local Indians gratefully took the trees for firewood. It didn't seem a site for a huge and delicate telescope.
The seeing on Palomar wasn't equal to the fabulous seeing on Mount Wilson, which benefited from the unusual atmospheric inversion in the Los Angeles basin, but by the early 1930s, with the lights of Los Angeles already a problem for the telescopes on Mount Wilson, the remoteness of Palomar had become an advantage. The Observatory Committee pursued an extensive program of measuring the seeing at a number of sites in Southern California and Arizona, and Caltech geologists were sent to explore the earthquake dangers of several potential sites. Alternately ignoring and countering the campaign by the eastern astronomers, in March 1934 Hale and his colleagues chose Palomar as the site for the new telescope. Most of the mountain was by then in cattle grazing. That summer, Henry Robinson of the Observatory Council began negotiations with the cattlemen. Despite the Depression plunge in real estate prices, the cattlemen drove a hard bargain. It wasn't until September 21, during an early fall storm, that the ranchers, Caltech, and San Diego County reached an agreement in a weather-beaten cabin owned by the Beeches, one of the ranching families. At 3:00 A.M., after the last kerosene lamp had run dry, the final agreement was signed by candlelight.
The San Diego newspapers loved the story. "With the closing of the deal," one newspaper wrote, "Southern California was assured a scientific institution which will comprise one of the wonders of the world." By the end of the year, a CCC (Civilian Conservation Corps) camp had been built in the Doane Valley, west of the observatory site, to house the workers who would build the promised county road up the mountain. San Diego officials had already named the road the Highway to the Stars, and proposed changing the name of the mountain to San Diego Mountain, until outraged citizens wrote poems to the Oceanside newspapers demanding that the old name stay. John Anderson of the Observatory Committee wrote on behalf of Caltech to point out that since Palomar was the name on the topographic maps, changing it would result in confusion. The San Diego officials reluctantly gave in, and started printing publicity brochures with the observatory prominently marked.
By 1934, the telescope was also news again far beyond San Diego. In the quiet years when the telescope project had stayed out of the news, General Electric had tried to fabricate a mirror disc from fused quartz. Their effort consumed almost one-fourth of the entire budget of the telescope project, without creating a single usable telescope mirror blank. Hale finally broke off the collaboration with General Electric and asked the Corning Glass Company, famed for their new wonder glass Pyrex, if they could fabricate the mirror. Corning assigned the project to a young physicist named George McCauley, who quietly and methodically refined the procedures and materials, and cast a series of smaller discs before preparing for the challenge of casting a 200-inch disc of special Pyrex.
That February, Lowell Thomas, the handsome and celebrated newscaster whose broadcasts preceded the popular Amos & Andy show, spotted a mention of Corning in a script that the NBC studio had prepared for him. Between the sonorous "Good evening, everybody" that opened his broadcasts and the trademark signoff of "So long until tomorrow," Thomas liked to focus on a single story. The story he picked that night was a report that the Corning Glass Works in Corning, New York, would soon be casting the 200-inch mirror for the great telescope, pouring 20 tons of glass into a special mold to create the largest glass casting ever made, for the costliest scientific instrument ever designed, the biggest telescope in the world, an instrument designed to see further into the cosmos than had ever been possible. Thomas loved hyperbole. The Depression was already an age of superlatives, with the construction of the tallest building in the world (Empire State), the longest suspension bridge (Golden Gate), and the longest ocean liner (Normandie). Lowell Thomas pulled out all the stops and finished his story by announcing that the pouring of the mirror "was the greatest item of interest to the civilized world in twenty-five years, not excluding the World War."
America listened to the radio in 1934. Overnight, the great mirror for the 200-inch telescope became the focus of widespread interest, crowding even the sordid stories of the Lindbergh kidnapping off the front pages of the newspapers. Crowds rushed to attend the pouring of the disc; newspapers, radio stations, and moviemakers lined up to cover the story. The pouring of the disc in Corning, an exquisitely complicated and demanding procedure that required precise choreography with huge ladles, a covered and heated mold, and a tank holding 40 tons of molten fined Pyrex, attracted such crowds that ticket offices were set up outside the factory, railings had to be erected inside the factory to allow the ticketholders each a few minutes to view the event, and diversions were provided to entertain the crowds while they waited for their few minutes of viewing the casting process. A Depression-wracked public seemed to find in the ambitious project the hope, heroes, and visions of progress and achievement that could temporarily let an ailing nation forget the troubled world. As the ladles of glass were poured into the mold, the crowd in the gallery sang "I'm seeing the world through rose-colored glasses."
Technical difficulties at the end of the casting spoiled the disc in the mold, and a second one had to be quietly poured months later. But to the crowds who had gone to Corning, and the thousands who had followed the event on their radios and in their newspapers, the technological triumph of the mirror disc became a symbol of hope and faith in the future of America. For a year, while the great disc slowly cooled in an annealing oven, newspaper readers hung on the stories of the flooding of the Chemung River that cut off power to the annealing oven, and the heroic effort by McCauley and his Corning co-workers to move the transformers to higher ground, restore power, and salvage the annealing cycle of the precious disc. The unveiling of the disc in the midst of a severe upstate New York winter brought more eager crowds to Corning. When a railroad news release revealed that that the disc would be transported across the country by train to the specially built optics laboratory on the Caltech campus, all of American readied for its chance to see the triumph of American technology.
Four railroads cooperated to carry the disc on a special train of only three cars: the engine flying the jaunty white flags of a special, followed by a tender, the special well-car that held the disc on edge with its covering panels of steel, and a caboose for the railroad workers entrusted with the precious cargo. There were efforts to keep the route unpublished, but since many trains across the nation had to be held up or rerouted to allow the 17-foot high disc the right of way for tunnels and underpasses, newspapers across the country were soon posting the schedule. The special train moved at a stately 25-miles per hour during the day; at night it was parked under guard. Everywhere it went, it was mobbed. Police had to be called out to control the crowds in Buffalo, Cleveland and Kansas City. In small towns across the prairies, work was suspended and schools let out so men, women, and children could line the tracks, with toddlers poised on their grandfathers' shoulders so they could see "The Giant Eye."
When the train reached Pasadena, the disc was trucked to the specially-designed optics laboratory on California Avenue. Few could imagine that it would be thirteen years before the doors of the building opened again to move the great disc up to the telescope that awaited it on Palomar Mountain. During the long years of painstaking grinding and polishing, thousands walked through the glassed-in visitors' gallery and heard the explanation of the excruciatingly slow process unfolding on the floor of the optics lab, where men in white suits and rubber soled shoes watched over enormous machines, sloshing slurries of fine abrasives and later polishing rouge and water under the slowly rotating tools that would grind the face of the disc flat, then into a concave shape, and finally to the demanding paraboloid figure of a primary mirror. The process went on so long that commentators and humorists like Robert Benchley had begun to chide the effort. "What do they do with gigantic telescope discs out in California--eat them?" Benchley asked in his satirical columns.
While tourists in Pasadena watched the tortuous progress of the white-suited opticians in the Optics Laboratory, in a nearby building machinists in temperature-controlled rooms were carefully grinding the enormous gears that would drive the telescope; the smoothness of the telescope's movement and it's ability to track celestial objects depended on the precision of the drive and control mechanisms. Like the work in the optical lab, the machining was a process of invisible progress. The favorite question of visitors--"When will it be done?"--was invariably answered with evasions.
Other tourists found their way up Palomar Mountain. The once remote mountaintop now had a one million gallon water tank, used initially to mix concrete, and later to supply the community that would live year-around at the observatory. A generating plant with main and auxiliary diesel engines and generators had been built only after a study of how to isolate the vibration of the huge diesel engines so it would not affect the nearby telescopes. Footings for the telescope were blasted and poured by Caltech students and engineers, and the framework for the dome was built in place by Consolidated Steel of Los Angeles.
To the visitors who watched the structure go up, but for the shape and proportions, which were almost identical to the Pantheon in Rome, the steel framework seemed almost ordinary, providing little hint that this was the largest welded structure in the world, or of the complex insulation and electrical systems the dome would house. A visitor in the mid-1930s might have seen a strange machine rotating around and around the frame and asked what it was for. The purpose was to grind the top rail of the steel frame on which the cars that supported the rotating dome would ride smooth and level. When the job began, the workmen on the site assumed it would have to be ground to a tolerance of .001 inches, a precision normally reserved for laboratories and machine shops, and difficult to achieve on an outdoor steel structure, where changes in the ambient temperature and the sun shining on the steel could cause the steel to expand or contract by far more than the allowed tolerance. Instead, the astronomers and engineers in Pasadena made their specification both simpler and maddeningly more difficult to achieve: they wanted the rails ground so there was no measurable vibration when the cars that would carry the dome moved. In the snow, rain, wind, and freezing temperatures of the top of Palomar Mountain, grinding the rails took months.
By the late 1930s, the dome was enclosed. The enormous components of the mounting of the telescope, designed in a cooperative effort of Caltech and Westinghouse engineers, with many of the final design problems worked out by a young Dutch engineer named Rein Kroon who traveled with his family to Pasadena, were fabricated at the South Philadelphia plant that Westinghouse normally used to build huge marine turbines. Some components, too large even for Westinghouse's machines, had to be machined at the Baldwin Locomotive Works and Westinghouse's huge East Pittsburgh plant. A special annealing oven had to be built for the huge fabrications. The components were shipped to California via the Panama Canal, trucked up the mountain, and assembled into a telescope mounting on the mountain. But for the lack of the mirror, which was slowly taking shape in the laboratory on California Avenue, it looked like a working observatory. Byron Hill, the onsite director, trained as a civil engineer and a master of concrete, fabricated a concrete disc to approximate the weight of the mirror blank so the telescope could be balanced and the mechanical and electrical systems installed and tested.
The telescope, impressive to behold as it moved on its huge equatorial mounting inside the immense dome, still had a concrete disc instead of a working primary mirror when Pearl Harbor put the entire 200-inch telescope project on hold. Many of the people working on the project stayed together during the war on rocket research teams under the auspices of Caltech, but with the war effort calling for maximum production of periscope mirrors and lenses for aerial cameras, the optics laboratory and machine shops that had been working for years on the telescope were turned over to war work. The unfinished mirror, after six years of grounding and polishing within a few wavelengths of the desired figure, was crated and leaned against a wall of the optical lab. There had been some scattered Japanese aerial attacks on the American mainland, rumors of more were constant, and Caltech, with its aeronautical design laboratories and research facilities was a prime target. All they could do was pray that the disc would survive the war intact.
The war that put the project on hold also changed the rules of Big Science. Before the war, George Hale's Old Boy network had been the thread that linked the diverse people, institutions, corporations needed to design and build a machine as immense, complicated, and demanding as the 200-inch telescope. With the demand for wartime research and production, agencies like the OSRD (Office of Scientific Research and Development) commandeered the facilities of entire universities and corporations. Research efforts like the Manhattan Project redefined the limits of Big Science, bringing thousands of scientists and engineers, a virtually unlimited budget, and a huge network of facilities together. The 200-inch telescope, only a few years before the biggest venture of science, suddenly seemed a small project by comparison.
At war's end, polishing and testing quietly resumed on the great mirror. There were occasional visitors to the gallery, but what had been the miracle of science and American achievement in the depths of the Depression lost some of its glitter in the postwar glare of atomic bomb tests, as the GIs came home and Rosie the Riveter returned from the factories to become a homemaker again. Quietly, the opticians polished and tested the mirror, balancing the dream of perfection that demanded another and yet another month of polishing against the impatience of the astronomers who had been waiting almost two decades for the telescope. Finally, on October 3, 1947, the Caltech publicity office issued a press release: "The most daring optical job every attempted by man was finished today--polishing of the giant 200-inch telescope mirror for the Palomar Mountain Observatory."
The End of the Journey
Irving Krick's forecast for the two days it would take to truck the mirror to Palomar had predicted clear weather. By the end of the first day, the mirror had reached Escondido, a distance of 126 miles. The average speed had been just under 11 miles per hour. The misty skies of early afternoon had turned into a steady, cold rain, and the thermometer was falling.
By the next morning, the visibility was marginal. The official weather reports said it was 150 feet; workmen remembered it as 50 feet. For the climb up the mountain, the lead tractor was joined by two other tractors pushing the trailer from behind. The Highway to the Stars had been designed and built for this cargo, engineered so that the crated disc would just clear each turn. There was no room for a Highway Patrol escort. Byron Hill met the cargo at the bottom of the mountain and rode up standing on top of the crated disc, shouting directions to men who walked alongside and ahead of the tractors and trailer to mark the edges of the road. The cold rain turned to a mixture of sleet, ice, and snow. The visibility was so poor the drivers of the second and third tractors couldn't see the puffs of exhaust from the first tractor; they coordinated their gearshifts on the grades by listening for the sounds of the engine and transmission of the lead tractor.
Steadily, the three tractors climbed the grade with their priceless cargo. When the reporters' cars stopped to take photos, men would have to get out and push to get them started again on the slippery road surface. Once the tractors started up the mountain, there was no stopping, only the slow steady climb from the desert floor to the mile-high top of the mountain. It was 11 A.M., four hours ahead of schedule, when the lead tractor rolled through the observatory gate. After a break for coffee to relax taut nerves, Lloyd Green, a driver with 25 years experience at Belyea, backed the trailer through the doorway in the side of the dome that had been waiting for a decade for the priceless mirror.
Collier's, Life, and Time all sent reporters to do features on the telescope, only to discover that it was a long way from ready. Before the telescope could go into operation, the mirror needed final figuring. Ike Bowen, the newly appointed director of the Observatory, had to conduct tests of the mirror. Dozens of other experimental systems--the oil pressure bearings that carried the enormous weight of the telescope, the unusual yoke mount, the active supports for the back and edges of the mirror, the drive and control system, and the interlocking drive mechanism for the dome--needed to be tested and refined. The publicity about the telescope had promised so much for so long that rumors of the early tests prompted much discussion, especially among those who had criticized the project from the beginning, that the telescope would not live up to its claims.
By the time the mirror arrived on Palomar, with so much work yet to be completed, the project had run out of money. The Rockefeller Foundation had made a supplementary grant of $550,000 to cover wartime costs, delays, and some additional equipment and auxiliary telescopes for the observatory, but even those funds were exhausted. And the earliest tests were not promising. The mirror needed substantial figuring. The early trials at aluminizing the mirror failed dramatically. The mirror supports, complex mechanical devices that were supposed to push and pull on the back of the mirror to help maintain its shape as the telescope moved, suffered from hysteresis and were not doing their job. Parts of the telescope mounting moved too easily, introducing vibrations which had to be dampened by adding devices to increase the friction of the mount.
Week after week, the mirror was painstakingly tested on stars--the ultimate test of a telescope--then removed from the telescope for refiguring, sometimes only a few minutes of polishing of tiny areas that showed up in Ira Bowen's analysis of the tests. Then it would be remounted for more testing, only to be removed for yet another round of polishing, initially with a portable polishing machine, later with tiny hand tools, and finally with carefully applied rouge or powdered walnut shells under the pressure of a thumb. Trial after trial of the aluminizing failed until a vacuum pump from the Oak Ridge installation of the Manhattan Project was brought in to overcome the leaks in the aluminizing tank. The mirror supports were quietly redesigned and rebuilt. The official First Light of the telescope was in January 1949. The famed Edwin Hubble, who had devoted almost as much time to publicizing himself as to his considerable discoveries in cosmology, exposed photographic plate P.H.-1-H6. Hubble pronounced the telescope a glorious success.
When the astronomers were finally allowed to begin observations on the telescope, it was all they had hoped for and more. The superior light-gathering power of the great mirror was able to resolve distant objects beyond the reach of other telescopes, the elegant control systems increased the efficiency of the night assistants and astronomers and hence the productivity of observation runs, and the stability of the telescope enabled astronomers and engineers to utilize a powerful new instrumentation to extend the reach of the telescope. Soon, reports of significant discoveries came so frequently that Allan Sandage recalled, "Those were the days when you'd come down from Palomar and everyone would expect you to come down with a pot of gold. Sometimes, almost always, it worked: new quasars, the biggest redshift; variability; are they galaxies or are they nearby?"
In the course of its celebrated twenty-year construction, the 200-inch telescope had involved so many pathbreaking technologies and had claimed and been awarded so many superlatives that it had gradually acquired an aura of being the ultimate telescope, the perfect machine. The 200-inch telescope was so celebrated in the popular press as well as the scientific journals that the design elements became a standard, copied in part or wholesale for future telescopes like the 120-inch telescope at the Lick Observatory (built from a glass blank that had been fabricated originally to use in testing the 200-inch mirror), and an 84-inch telescope at Kitt Peak, in Arizona. Some argued that the 200-inch defined the standard for large telescopes for so long that it retarded the development of newer ideas.
The aura of being the ultimate telescope that had grown up around the project so infused the machine and the men around it that sometimes they were reluctant to admit when the 200-inch telescope did not meet the specifications that the designers and the pressure of worldwide publicity had attached to the machine. The much-talked-about computer that was supposed to compensate and control the pointing of the telescope was never built. Many Palomar staffers knew it was not there, but obfuscated their answers even to direct queries about the computer. In 1965, Bruce Rule, the chief engineer for Palomar, referring to rate corrections for refraction, one of the functions the computer was supposed to perform, said, "We don't do this automatically now,"7 implying that at an early time they did do the correction automatically, which was not true. A year later, Rule wrote that "We have provided for systematic corrections for tube deflections, but because the structural compensation was so good we didn't have to use it."8 Steven Smith's plans for an analog computer, expanded and refined by an engineer named Ed Poitras, had indeed provided for the corrections. But the computer was never built.
On another occasion, Ira Bowen wrote for a symposium on telescopes: "The sidereal-rate tracking mechanism was constructed to meet the specification that the accumulated error should not exceed 1 second of arc per hour...It was also specified that, within 45 degrees of the zenith, setting errors should not exceed 5 seconds of arc."9 Those impressive specifications were in the plans for the telescope, and were much-publicized. Bowen's careful language never admits that the computer that would have been needed to achieve those corrections and that precision of tracking was never built. In fact, the RA drive mechanism and variable-rate clock drive of the telescope were so accurate, and the selsyn-driven control panels were so convenient and pleasant to use after years of struggles with the balky control mechanisms of the Mount Wilson telescopes, that the telescope functioned well without the missing computer. After all the publicity, Rule, Bowen, and others associated with the telescope couldn't bring themselves to admit that it wasn't a perfect machine.
Over its long career, the two-hundred inch telescope may be the most productive astronomical instrument in the world. Walter Baade's early calibration of RR Lyrae variable stars in the Andromeda galaxy, Allan Sandage's long efforts to refine the Hubble constant, and Baade's brilliant unraveling of stellar evolutions and populations all relied on the 200-inch telescope. It was on the 200-inch telescope that Maarten Schmidt obtained the enormously red-shifted spectra of strange objects he identified as quasars, beginning the race to discover ever more distant objects---distant galaxies, H II ionized clouds, quasars---that led astronomers out to the very edges of space and back to the early moments of the universe.
By the 1970s, the development of CCDS, electronic detectors hundreds and then thousands of times more sensitive than even dramatically hypered film emulsions, extended the reach of the telescope yet again. New instruments, some as large as a refrigerator, were built to house and cool the sensitive detectors and their associated optics. The 200-inch telescope, with its massive mounting and with the foresight of designers who provided multiple observation positions, easily accommodated the new instruments that no one could have imagined a half century before when the telescope was designed.
The last quarter of the twentieth century has seen newer telescope designs and innovations that were impossible to achieve with the technology of the 1930s and 1940s--fused quartz mirrors, superthin meniscus mirrors that maintain their shape through computer-controlled supports, lightweight honeycomb mirrors, mirrors cast in spinning ovens to cool in a dished shape to simplify the initial grinding and figuring. Remarkably, each of these new developments is a refinement of ideas that were explored in the building of the 200-inch telescope. There are bigger telescopes in operation now, like the twin 400-inch telescopes at the Keck Observatory in Hawaii, which use multiple-sectioned mirrors that are continually adjusted by computer-controlled actuators; even larger telescopes are under design or constructions.
The Hubble Space Telescope, in orbit above the earth's atmosphere, has redefined the astronomer's standard of seeing.10 Today, every major telescope is guided by a computer, and sophisticated software allows the use of simple and relatively lightweight alt-azimuth mountings instead of the massive equatorial mountings of the 200-inch telescope. Yet even there, the 200-inch telescope enjoys an advantage: on the newer alt-azimuth mountings, the instrument package has to be rotated to match the earth's rotation; the equatorial mounting of the 200-inch telescope needs no such rotation, which can make instrumentation simpler.
The site that once seemed too remote for a telescope is today one of more easily reached observatories, compared to clusters of research observatories in the Chilean desert and on Mauna Kea in Hawaii. The lights of Los Angeles and San Diego, considered safely distant 70 years ago, encroach on Palomar today. Yet the 200-inch remains a premier research instrument. In 1995, Dr. Shrinivas Kulkarni used the 200-inch telescope to discover the first known brown dwarf star. Earlier this year Dr. Stephen Eikenberry of Caltech used a high-speed infrared camera on the 200-inch telescope to capture a sequence of images, shot at 10 frames a second, to create a "movie" of black holes swallowing matter inside our galaxy.
And even as larger telescopes come into service, the 200-inch Hale telescope remains a unique symbol. After a half-century of journalism and documentaries, the 200-inch telescope is what we expect a large telescope to look like. The proportions of the dome and the sheer mass of the machine are humbling. We have seen so many photographs, or Russell Porter's elegant line drawings, that the sleek battleship grey mounting and the stark black and silver control panels, industrial designs that paralleled the first diesel locomotives and the first streamlined cars, seem familiar. From the glassed-in visitor's gallery, we can visualize how the telescope works. It is a far cry from today's machines, where the primacy of silicon over steel has brought us black box technologies, machines whose inner workings remain shrouded in mystery.
After fifty extraordinary years of active research, the great machine that for two decades captivated and motivated a nation in the throes of Depression and the recovery from the World War, and for the next half-century revolutionized cosmology and astronomy by reaching into the farthest edges and early history of the universe, remains a monumental tribute to men of extraordinary insights in design, engineering, materials, and fabrication technologies, and to an era when the remarkable American "can-do" spirit in a time of widespread economic hardship brought the skills and energy of a nation together to create an enduring masterpiece of science and technology.
1. The history of the building of the 200-inch telescope is chronicled in Ronald Florence, The Perfect Machine (HarperCollins, 1994).
2. Seeing is the term astronomers use to refer to the steadiness of the atmosphere. A site with good seeing will produce pinpoint images of stars and other distant objects. The twinkling of stars that charms lovers is the bane of astronomers. Seeing is measured in arc-seconds, with sub-arc-second seeing considered very good.
3. Figure is the term opticians use for the precise shape that is ground into an astronomical mirror. The dimensions are so precise that opticians routinely use wavelengths of light as a measure.)
4. "Report by W. J. Hussey on Certain Possible Sites for Astronomical Work in California and Arizona," Appendix A to Report of Committee on Observatories, Carnegie Institution of Washington, 1903.)
5. The road was officially named after Nathan Harrison, a black man who called himself "the first white man on the mountain." Harrison had come to Palomar in 1848 as a slave, and worked at a mining claim in Rincon. No one knew how he survived year-round on the mountain. His only source of income was tips from travelers grateful for the buckets of water he brought for their struggling teams. "Uncle Nate" died in 1920, at the age of 101.
6. The initials represent Palomar, Hale [telescope], and Hubble. Hubble chose as his first target NGC 2261, a galactic nebula with a variable star, R Monocerotis, that he had discovered at the Yerkes Observatory years before at its apex.
7. "The Construction of Large Telescopes," Proc. IAU Symposium, No. 27, ed. D. L. Crawford, (1965), p. D15. I am indebted to Patrick Wallace, of the Rutherford Appleton Laboratory in Oxford, for this and the following references, and for his superb sleuthing into the question of the missing computer. On another occasion, Rule claimed that the telescope could achieve 0.25 arcsec. pointing accuracy. Patrick Wallace has pointed out that the selsyn dials on the original control panels are calibrated to one second of time on Right Ascension and 10 seconds in Declination. Reaching Rule's claimed 0.25 arcsec accuracy would require reading those dials to one-sixtieth of a division on the RA and one-fortieth of a division on the Declination.
8. Bruce H. Rule, "Accurate Guidance with Large Optical Equipment," NASA Report No. SSS-67-78 (1966), p. 17.
9. Gerard P. Kuiper and Barbara M. Middlehurst, ed. Telescopes (University of Chicago Press, 1960), p. 10.
10. It is an interesting measure of inflation and the sliding scale of Big Science to compare $600 million repair mission to replace instruments and compensate for the misfigured primary mirror of the Hubble Space Telescope with the $6 million total design and construction cost of the 200-inch telescope, including the 48-inch Oschin Schmidt camera.
Images from this article depict the installation and early history of the Palomar Observatory.
Ronald Florence is an historian and novelist, the author of six books, including The Perfect Machine. He was educated at the University of California, Berkeley and received his Ph.D. from Harvard University. He first visited Palomar as a high school student shortly after Sputnik was launched. He now lives on the Connecticut shore.
The Perfect Machine: Building the Palomar Telescope, a book by Ronald Florence on the building of the 200-inch telescope.