The Perfect Machine

by Ronald Florence

  On the question of a site, as on most issues concerning the big telescope, George Hale had strong views. From the time he had organized the Yerkes Observatory, Hale had been convinced that the old days of an observer going up to a mountain with a sketch pad to record what he had seen were long gone. The new problems of astrophysics required that an observatory be close to well-equipped research libraries and laboratories in related disciplines like physics and spectroscopy. The modern telescopes Hale was building needed not only darkrooms and auxiliary equipment like blink stereo comparators, but constant attention and experimentation with new sensors, emulsions, photographic and spectrographic instruments, and auxiliary lenses. Astronomers were constantly proposing new observation programs at the limits of the telescope’s resolution and light-gathering powers, with complex instruments that could only be built, modified, and repaired in dedicated optical and mechanical shops. The road from the offices and shops on Santa Barbara Street in Pasadena to the telescopes and Monastery on Mount Wilson was well worn.

  When Hale first built the solar telescopes, and then the sixty-and one-hundred-inch telescopes, Mount Wilson had been an ideal site. It was close to the laboratories in Pasadena, and the peculiarities of the local geography and weather created remarkable observing conditions on the mountain. Mount Wilson was soon famous not only for the instruments on the mountain but for the seeing. Many astronomers thought that on a good night the atmosphere over Mount Wilson was so still, the images of the stars so well defined, that it was perhaps the best seeing in the world.

  Over the years the seeing (atmospheric turbulence) at Mount Wilson had not deteriorated, but for dark-sky work—photographic or spectrographic study of galaxies and other distant objects too faint to record on a photographic plate when the moon is up—Mount Wilson had begun to suffer from its proximity to Los Angeles. Other cities grew up, becoming more dense. Los Angeles, already the fastest-growing city in the nation, spread. By 1928 the city and surrounding towns reached right to the base of Mount Wilson. The San Gabriel Valley below the observatory glittered with lights at night, more than even the fogs could obscure. The Mount Wilson staff were sensitive to the issue. When Rose and Thorkelson visited Mount Wilson, Hale warned Adams to stay with them at all times; “if any questions about lights in the Valley” came up, Adams was to “show how easily they [could] be met.”

  For 90 percent of the observations that a new telescope would do, including most spectroscopy, bolometric observations, and direct photography with moderate exposures, the conditions on Mount Wilson were still superb. But for very long exposures on faint objects at the limit of the telescope’s reach—exactly the work for which the bigger telescope was most important—even Hale acknowledged that “the illumination of the night sky [below Mount Wilson] may be sufficient to make trouble.” To fulfill its mission of extending the limits of the observable universe, the new telescope would have to be at a site more remote than Mount Wilson, far enough from any city that even the unpredictable population growth and sprawling development of a Los Angeles wouldn’t interfere with the future use of the facility.

  For Hale the siting question was a tricky balance: How far from Pasadena would they have to go to achieve the dark skies and good seeing they needed? How far was too far from the Santa Barbara Street laboratories and optical facilities, and the new astrophysics laboratory that would be built on the campus of the California Institute? Ferdinand Ellerman and Milton Humason, observers with considerable experience on the big telescopes, and both veterans of the early days when Humason had led mule trains up Mount Wilson, cautioned against a site that was too inaccessible. Hale also liked to quote a Henry Norris Russell story about a mining engineer sent to investigate a claim offered at a suspiciously low price, who telegraphed back east: ORE THERE. UP TO SAMPLE. LOTS OF IT. WILL NEED PACK TRAIN OF BALD EAGLES TO GET IT OUT.

  Long before the grant was confirmed, arguments about the virtues of one peak or another, and the potential seeing at various sites, were a staple of the conversations at Mount Wilson and Santa Barbara Street. By the end of the summer of 1928, Hale had instituted a regular program of calibrated measurements at the better potential sites. One of Russell Porter’s earliest tasks was to design a small telescope to be used specifically for these seeing tests. He came up with a four-inch refractor of thirty-six-inch focal length, used with a 210-power compound microscope eyepiece. The resulting telescope magnified images 750 times, which would readily show up atmospheric turbulence. Porter’s design was simple to build, with four steel legs that could be pushed into the ground to steady the telescope. The telescope was designed to observe Polaris, the pole star, which remains in the same position in the northern sky, at least over a relatively short period, so the telescopes could be made portable without motor drives that would require complex alignment procedures. The magnification was so high that Polaris would travel across the field of view of the little telescope in ten minutes, but that was long enough to record the seeing.

  To complement Porter’s telescope design, Anderson developed a technique of recording the size of the “tremor disc” of Polaris on a calibrated scale, so measurements by different observers, at different sites, could be compared. With practice a trained observer could get a reading in two or three minutes.

  Ellerman, who had started with Hale at the old Kenwood Observatory in Chicago, developed a site evaluation program which recorded estimates of the seeing, the weather, the incidence of fog, and other factors that could affect the use of a large telescope. Humason was also recruited for site research, and Hale suggested equipping amateur observers with special eyepieces and instructions from Hubble or other experienced astronomers so they could aid the project by measuring and recording the seeing at different sites.

  By fall, the list of potential sites for the telescope included Flagstaff, Arizona, various locations in the Mojave Desert, Winona, Bellemont, Barstow, and Hot Springs Mountain in San Diego County, Table Mountain behind Mount Wilson, Pine Flats, Union Flat, Holcomb Valley above Big Bear, Volcan Mountain near the Julian Flats, Rattlesnake Flat, Pleasant View Ridge, Lake Arrowhead, Mono Lake, and Catalina Island—all within a day’s driving time of Pasadena. It seemed like a thorough program to evaluate the best site for the telescope.

  Although he encouraged the site survey program, Hale already had strong opinions about the future site. He had never forgotten the inviting description of Palomar Mountain that W. J. Hussey had written on his 1903 survey for the Carnegie Institution. “Nothing prepares one for the surprise of Palomar,” Hussey had written, “… a hanging garden above the arid lands.” In 1903 Palomar had been too remote for an observatory. A quarter century later, what had been a disadvantage had become a benefit. Palomar was far enough from Los Angeles and San Diego to not be threatened by their light pollution. Before the measuring instruments for the broader site survey were ready, Hale suggested a program of observations at Palomar, including comparisons of the brightness of the night sky with the sky at Mount Wilson, which they would do by comparing photographs of the same star field taken from different sites with the same short-focus portrait lens. In those early tests, Palomar had none of the light pollution problems of Mount Wilson. Hussey had not measured the seeing, but he predicted that “the remarkable stillness, the steady temperature, and the evergreen covering of Mount Wilson could not be found on Palomar.”

  Hale was determined to prove him wrong.

  Hale’s strong ideas were a perfect target for the complaints from other astronomers. A few who had worked at Mount Wilson or Yerkes sent their comments and suggestions directly to Hale. Hale answered politely but firmly, explaining that to draw on the concentrated experience of the California Institute and Mount Wilson, the telescope had to be at a site no more remote than Arizona. Anderson told Arnett that the sole question in the site evaluation program was how many nights of good seeing would be available at each location. He conceded that southern Idaho, Nevada, western Colorado, or other sites that had been sug
gested might be clearer at times than the sites they were looking at in Southern California, and might even have seeing comparable to Mount Wilson, but they had storms, which are rare in Southern California. It wasn’t a convincing argument, at least not one Arnett could use to silence the campaign directed at his office.

  When he had his mind made up, George Hale could be stubborn and clever in equal parts. To blunt the controversy, he agreed to appoint a site committee for the telescope, with a membership that included outsiders: Charles Abbot of the Smithsonian Institution, who had arranged the great debate of 1920; Professor Charles Marvin, the chief of the U.S. Weather Bureau; Dr. W. S. Humphreys, a professor of meteorological physics at the Weather Bureau; and Robert Aitken, the assistant director of the Lick Observatory. Even Shapley couldn’t find fault with the proposed outside members.

  Arnett took the proposal to President James Rowland Angell of Yale University and Charles P. Howland of the Council on Foreign Relations, whose diplomatic skills presumably could broker between the warring parties in American astronomy. Both men urged that any site committee have a “free hand,” by which they meant it should not be dominated by Hale.

  Hale, anticipating the opposition, had already prepared an agenda for the committee, with criteria for a site:

  •The latitude had to be between thirty degrees and thirty-five degrees north, so the telescope could observe stars from the celestial pole to south of the celestial equator.

  •The altitude of the site had to be from six to eight thousand feet. The lower figure was the minimum to guarantee adequate sky transparency. A site higher than eight thousand feet would be subject to excessive snowfall, and heated air rising from bare rocks above the timberline.

  •The annual and daily temperature range had to be small, and the winds minimal, to produce the best seeing.

  •Freedom from cloudiness.

  The only sites that met those considerations were in the southwestern United States or northern Mexico.

  At that point Arnett asked Hale to come to New York to discuss the matter. In an era when it took four days to cross the country by train, an invitation from an official of the funding foundation was not to be treated lightly.

  Hale, in no mood for a confrontation, stalled. The Los Angeles lights had become a problem, he admitted, but “the results thus far obtained point to Palomar as the most promising [site], as the ‘seeing’ is distinctly better than at Mount Wilson, while the sky is much darker and purer.” His long years in astronomy, and especially in Southern California, gave Hale an advantage in arguments: He drew examples from the results of double-star studies at Yerkes and at Lick, episodes from his own unsuccessful experiences at Pikes Peak, the threat of a single dust storm “such as I have frequently seen in Egypt,” and the problems of extremely cold weather numbing the fingers of observers. “The problem … is much more complex than it may seem at first view.”

  To undercut Shapley’s arguments for a Southern Hemisphere site, Hale cited Hubble’s recent publications on the spiral nebulae, which had been celebrated in the popular press. Hubble had written that the nearest cluster of extragalactic nebulae, the only one with spirals large enough for study with a two-hundred-inch telescope, was in the northern sky.

  By contrast, Hale explained, the Southern Hemisphere wasn’t yet sufficiently explored by smaller instruments to be ready for the research efforts of the largest instrument in the world. In a naked jab at Harvard, he pointed out that the observations at southern stations were generally “conducted in a routine way by one or two assistants, cut off from contact with productive thinkers and of necessity pursuing their duties in a mechanical manner. It is not from such sources that prime advances in principles or methods of observation are likely to proceed. Not one but several investigators of the highest type, constantly stimulated by personal contact and by daily discussion with men of the same high calibre working in related fields, are absolutely necessary if we are to secure such advances as we have in view.”

  Finally Hale threw in an argument that could be expected to either win the day or ruffle the feathers of Wickliffe Rose’s successors at the IEB: “A consideration regarded by Dr. Rose as paramount must be kept constantly in mind. This is the importance of establishing the two-hundred inch telescope within a few hours’ ride of such a strong group of investigators as we have in Pasadena.”

  Arnett, with a foundation officer’s hesitancy to interfere, assured Hale that he did not question the merits of a site in Southern California, but only the procedure followed in selecting the site. Perhaps, he suggested, they should hold a conference to discuss the site, with expenses paid by the IEB. With hindsight, it is easy to read between the lines of Arnett’s letters. If the California group made a show of following an open search procedure, he seemed to be suggesting, they could have a free hand in picking a site. He wrote again and again, insisting that they either have a conference or that a special committee, completely independent from the Pasadena group, be appointed to study the site question.

  Each time Arnett wrote, Hale stonewalled. As so often happened in tense moments, his demons came back to torment him, and the arguments of the whirligus were even more ferocious and more demanding than the brouhaha over the location of the telescope. Miss Gianetti made excuses for him when he retreated to his curtained room to seek the modicum of respite that darkness and silence could provide. Hale wasn’t beyond taking advantage of the demons. If the doctors would permit him, Hale wired back, he would come to New York. For good measure he reminded Arnett that when they first discussed the grant Rose had agreed to a site within easy access of Mount Wilson and the California Institute.

  It was the end of October before Hale allowed that he was well enough to make the trip to New York, accompanied by Walter Adams. They met at familiar stamping grounds, the University Club, with Arnett and Max Mason, who had just been named president of the Rockefeller Foundation.

  By then the program of measuring the seeing at sites in Southern California and Arizona, and the plans for the Astrophysics Laboratory at the California Institute, were so far along that Arnett could do little more than explain that it was good politics to at least acknowledge the suggestions and comments of astronomers at other institutions. Harlow Shapley was only half conciliatory. It would take at least five years to make a two-hundred-inch disk, he wrote to Hale, citing private information he had received from General Electric’s West Lynn laboratory. Hence he urged that Hale take plenty of time, two or three years, to test a site. It was the last Shapley would argue on the topic.

  Hale had won the first battle over the telescope. But the pressure of the dispute and the trip to New York took their toll. The demons were relentless now. Within a month Hale made plans for an extended trip abroad. “The pressure I have been under … a much larger amount of work than I can continuously carry, have delayed my correspondence and forced me to the conclusion that I must get completely away from work for two or three months.” He booked passage for a Mediterranean cruise, sailing from New York on January 22, 1929, hoping “to take a complete rest of several months.”

  Before he sailed Hale wrote a memo to the Rockefeller Foundation staff, on a new letterhead of the Astrophysical Observatory of the California Institute of Technology, summarizing the progress to date on the project. He boldly listed the decisions that had been made: fused quartz for the mirror, under the personal direction of Elihu Thomson at General Electric; the J. G. White Engineering Company, headed by his friend Gano Dunn, for general supervision; Warner & Swasey, the veterans of the Lick and Yerkes telescopes, and recently of a number of large reflectors, for the mounting, with assistance from Francis Pease and General Carty. The project was in the hands of the University Club’s best men.

  The Mount Wilson opticians would grind and polish the mirror disk on the site of the telescope. Carty and Dunn were on the board of the Carnegie Institution, but the procedures he had outlined, Hale explained, were “designed to secure the best possible results wi
thout involving the Carnegie Institution of Washington in any expense, or calling for much of the time of its research men, or even of existing shop facilities during the construction period.”

  Hale made the project sound simple. He had assembled the most talented astronomers and telescope designers, gotten the largest grant ever, could call on the most distinguished leaders of industry and academe. He had the laboratories and staffs of both Caltech and the Mount Wilson Observatory available, and could draw on the collective experience of the men who had designed, built, and operated the largest telescopes in the world. Hale’s enthusiasm was so contagious that everyone else thought his estimate that it would take four to five years to finish the telescope needlessly pessimistic.

  Work in Pasadena began without him. Memorandums, correspondence, and minutes of meetings went back and forth from the solar laboratory, Santa Barbara Street, the California Institute, the Rockefeller Foundation offices, private contractors, and consultants, some solicited, some uninvited. Typewriters and carbon paper were already standard equipment in the business world by 1928. The handwritten correspondence of an earlier era had given way to a snowstorm of memorandums in multiple copies. Paperwork quickly began to fill file cabinets and old-fashioned correspondence boxes. The original Observatory Council and Advisory Committee begat subcommittees on site, optics, and myriad other topics, and before long the subcommittees were meeting regularly enough to have earned a permanence of their own. From an astronomer’s dream the project had begun to take on all the bureaucratic trappings of a major enterprise.

  Yet for all the flurry of business, there is a strange, otherworldly calm in these memoranda and minutes. In the newspapers the roller-coaster ride of the stock markets was front-page news throughout the summer and fall of 1928. In the minutes of meetings and the flood of correspondence from Hale and his colleagues about mountings and sites and disk designs and grinding machines and staff and budget and countless other details, there is nary a mention of the topic that seemed to dominate conversation everywhere else.