The Perfect Machine

by Ronald Florence

  A few cosmologists offered theories to explain the contradiction. “After all,” de Sitter wrote, “the ‘universe’ is an hypothesis, like the atom, and must be allowed the freedom to have properties and to do things which would be contradictory and impossible for a finite material structure.” Hubble wanted no part of the sleight-of-hand explanations:

  We face a rather serious dilemma. Some there are who stoutly maintain that the earth may well be older than the expansion of the universe. Others suggest that in those crowded, jostling yesterdays, the rhythm of events was faster than the rhythm of the spacious universe today; evolution then proceeded apace, and, into the faint surviving traces, we now misread the evidence of a great antiquity. Our knowledge is too meager to estimate the value of such speculations, but they sound like special pleading, like forced solutions of the difficulty.

  Hubble’s answer to the dilemma was more observations, looking ever further into space, cataloguing and measuring the red shifts for more galaxies, until somehow the discrepancies could be resolved. “The next step will be to follow the reconnaissance with a survey—to repeat carefully the explorations with an eye to accuracy and completeness.” With the completion of the two-hundred-inch telescope and the Schmidt camera, which would survey likely areas in preparation for the deep probes by the telescope, the answers would emerge. Hubble planned to map the universe. The new telescope would be his tool.

  Hubble wasn’t the only astronomer with plans for the big telescope.

  In 1931, the year Hubble met Albert Einstein, Walter Baade arrived at Mount Wilson from Hamburg, bringing not only Schmidt’s idea for the wide-angle deep-space camera, but a remarkable skill at observing with large telescopes. Baade had spent 1926 at the Mount Wilson Observatory as a Rockefeller fellow, and he knew exactly what he wanted to do on the big telescopes. He would leave the discovery of ever-more-distant nebulae to Hubble; he wanted to know more about the nebulae. In photographs, even with the biggest telescopes, the nucleus of even a close nebula like Andromeda was a glowing mass. A few, like the nebula in Draco, gave off a bright line spectrum, as if they were a glowing gas. Others, like Andromeda, emitted what appeared to be a continuous, or “white,” spectrum, as if the nucleus were a glowing liquid or solid, or perhaps a collection of stars packed tightly together. No one had succeeded in resolving the nucleus into individual stars.

  Baade was a small, lively man, with a limp in one leg, a reluctance to publish until he was absolutely sure of his material, and a generosity of spirit that stood out in an increasingly competitive field of astronomy. He didn’t like the midnight snacks that the observatory provided, so he brought his own cheese and sausages, which he would share with the night assistants. Baade was a dark-time man, who observed when the moon was down. The light-sky men, those who got time when the moon was up, used their spectroscope gratings to analyze stars. Baade hoped for a lucky black night of clear weather and still skies, the superb seeing that would let him stretch the resolving power of the telescope to an even fainter image. “Those spectroscopists,” he said. “They don’t know how to eat, how to drink, how to love.”

  For a few years in the mid-1930s, Baade collaborated with Fritz Zwicky, who was using the eighteen-inch Schmidt camera on Palomar to find supernovas. It seemed a natural partnership: They both had German as a native language (Zwicky, though born in Bulgaria, was Swiss), and they shared an interest in the edges of cosmology, questions like the sequence of evolution of stars that would lead to supernovas and other extraordinary celestial happenings. Their agreement was that when Zwicky found supernovas with the Schmidt camera, Baade would follow up with a study of the light curves with the large telescopes on Mount Wilson. The collaboration worked for a while, and they did some promising work together, including pioneering investigations of the concept of neutron stars. But Zwicky, who got along well with secretaries and night assistants, couldn’t work with a coequal for long. He accused Baade of reneging on his part of the research and stealing credit for Zwicky’s own work. For good measure Zwicky threw in an accusation that Baade was soft on Hitler. Before long Zwicky’s verbal threats became so intimidating that Walter Baade refused to be alone with his former colleague. Baade later told other astronomers he was physically afraid of Zwicky.

  At Mount Wilson Baade was safe from Zwicky. Working as many dark-time nights as he could get telescope time, Baade searched for the secrets of the distant galaxies. Harlow Shapley had argued that the nuclei of the galaxies were only a glowing gas, but in one photograph taken with the sixty-inch telescope in 1920, Baade thought he could almost see individual stars in the nucleus of M33. He and Joel Stebbins, who had pioneered work with photoelectric devices to measure the intensity of light, refined the accuracy of measuring star brightness, and Baade began a long program of observing M31 in Andromeda. He was an extraordinarily careful observer, and before long he had photographs of the outer region of the nucleus that registered star images with the smallest angular diameters yet recorded. Yet, no matter what emulsions, corrector lenses, or tricks he tried on the one-hundred-inch telescope, the resolution of stars in the nucleus of Andromeda eluded him. It was, everyone agreed, a task for a bigger telescope. Baade joined the queue of astronomers eagerly awaiting the two-hundred-inch telescope.

  The dream of resolving the nucleus of Andromeda was only the first step of Baade’s ultimate goal. Hubble had searched for the geometry of the universe. Baade wanted to understand stellar evolution. He wanted to break down the populations of stars in the distant galaxies, to document and understand their evolution, and ultimately to be able to age-date the stars and the universe. Elsewhere chemists and nuclear physicists were exploring the complex reactions at the core of stars, the processes of nucleosynthesis that created the energy of the stars and the elements of the universe. Hans Bethe, a physicist, was exploring a theory of stellar energy, showing how almost all the energy generated by the most brilliant stars stems from a fusion reaction in which hydrogen is the fuel and carbon the catalyst. The theoreticians seemed to be outstripping the observers. In the Monastery at Mount Wilson and in the laboratories and seminar rooms at Pasadena, talk about the progress on the two-hundred-inch telescope was daily fare.

  The anticipation of the new telescope was much accentuated when Max Mason sent around a memorandum to the astronomers asking their thoughts on the idea of setting up facilities at the new observatory to permit an astronomer to be accompanied by his wife. There had been a long-standing debate on whether the astronomers’ residence at Mount Wilson was called the Monastery because of three early astronomers who had worked there: Monk, Abbot, and St. John; or because of George Hale’s rules that the accommodations remain strictly bachelor quarters. The newly married Harlow Shapley had put up with the then-difficult commute from Pasadena instead of accepting free accommodations in the Monastery, and astronomers making long runs on the telescopes had routinely griped about the too aptly named Monastery.

  Fritz Zwicky, taking advantage of the lack of rules at Palomar, had taken his wife for his runs on the “little” Schmidt camera and said he thought it had been a good idea. Walter Baade, agreeing for a change with Zwicky, urged breaking “occasionally from the tyrranic [sic] rule of the monastery…. For individuals like myself it would be a decided improvement over the present system as being practiced on Mount Wilson.” Not everyone agreed. Milton Humason, who had put in his time on the mountain as a mule driver and staff worker before he began observing, noted that if wives were there, observers would not make maximum use of the telescopes. He and Walter Adams opposed having more than one cottage available for use by an astronomer bringing his wife. No one raised the question of facilities for unmarried women, or a woman observer bringing her husband for an observing run. Women observers were still virtually unknown at Mount Wilson.*

  Mason decided to provide one cottage for observers, along with the residence facility. The name “Monastery,” brought over from Mount Wilson, stuck even before Russell Porter had finished his desi
gns for the building or the site, nestled in a wooded grove at some distance from the big dome, was chosen. The residence was solidly built, with metal studs, metal lath, and plaster walls. George Hale put in his voice on the furnishings, urging that the simplest furniture would be the most appropriate. “On Mount Wilson we never used window drapes, though rolling window shades are necessary.”

  The original design called for a copper roof, but the redheaded woodpeckers on the mountain found the copper inviting, punched holes to store their acorns, and later returned to harvest insect larvae from the acorns. The result was leaks in the roof, which ultimately had to be replaced with composite shingles. The woodpeckers also dropped acorns down the toilet vent pipes, so that the waste pipes were soon clogged with oak roots.

  The eighteen-inch Schmidt telescope, a few hundred yards down the slope from where the dome for the two-hundred was going up, was the only working telescope at Palomar, but astronomers from Mount Wilson and other observatories visited, marveling at the size of the new dome and the caissons that would support the mounting of the telescope. They had talked about the Big One for years, studied the drawings, discussed myriad details. Seeing the dome going up, visiting a site crawling with workmen, and the reality of a residence for astronomers, increased the anticipation.

  Palomar was still a wild, undeveloped spot. The climb up the mountain was difficult, and the dome site at the top, with the trees and shrubs cleared, created a barren plateau. But under the night sky, far from city lights, it was hard not to feel the closeness to the cosmos.

  In 1937 Byron Hill went on a camping vacation, and Mark Serrurier was asked to temporarily take over the supervisor’s task at the top of the mountain. While he was there he asked a woman he had been dating, Naomi, to visit him for a weekend. Serrurier waited until a dark night, when the carpet of stars was spread overhead, to ask Naomi to marry him. She felt so overwhelmed by the sky, the stars, and the power of the place that she deferred an answer until the next day. It wasn’t until she was halfway down the mountain that Naomi felt far enough away from the magic of the peak to say yes.

  As long as astronomers asked new questions, there would always be dreams of newer and bigger telescopes. This one felt different. It wasn’t just the size and already-growing fame of the two-hundred-inch telescope: The questions of astrophysics were so ripe, and the answers to the eternal cosmic riddles seemed so close, tantalizingly just beyond the grasp of the one-hundred-inch, that it was hard not to feel incredible impatience for the new telescope.

  27

  Passing the Torch

  Sinclair Smith, a bright young astronomer, came to Mount Wilson in the early 1920s. A year of study in England “settled him down,” and he was soon a regular member of the staff, investigating the physical constitution of nebulae and star clusters. By 1931 he and Fritz Zwicky were independently studying clusters of galaxies. Smith scrutinized all the available data on the Virgo cluster, measuring the differences of velocities of galaxies in the cluster, and concluded that the galaxies were moving too fast to stick together; a group with that little mass should fly apart. Zwicky coined the name “dark matter” for the missing mass. Cosmologists today are still searching for the dark matter to balance their equations.

  Smith was recruited to the two-hundred-inch telescope project to work on electronics, particularly instrumentation and the drive system for the telescope, the combination of motors, gears, and black-box magic that keeps the telescope accurately tracking objects as the earth turns through the evening. At first glance the task seems easy. The rotation of the earth makes objects appear to move across the night sky. Move the telescope to compensate for the earth’s motion and the objects appear to stand still. The equatorial mounting of the telescope, with its polar axis exactly parallel to the axis of the earth, made the basic motion a simple rotation. The basic task of the drive mechanism was to turn the telescope at the precise speed of the earth’s rotation, but in the opposite direction so that the sky appeared stationary.

  But turning the telescope the equivalent of one full rotation in twenty-four hours to match the rotation of the earth isn’t enough. The bigger the telescope, the more exacting the requirements for a drive mechanism. Atmospheric refraction, a minuscule offset of images as the azimuth of the telescope was raised or lowered from the horizon to the zenith, is magnified in a large telescope. The big telescope would be sensitive to eccentricities in the bearings, gears, or mounting structure. A bearing surface as true and smooth as the machine shop could produce, the surfaces honed to the precision of a watch, would still introduce periodic errors, “bumps” in the motion of the telescope. Over the course of a long exposure, an uncorrected bump would ruin an image or degrade the quality of a spectrum by moving the light from the object off the slit of the spectrograph.

  The sixty-and one-hundred-inch telescopes, after decades of use, still had balky quirks in their drive and control systems. Baade used to test budding observers on the sixty-inch telescope at Mount Wilson by seeing if they recognized and compensated for the periodic error in the gear train that had the telescope creep ahead of the stars it was tracking every eighty seconds. By listening for the relays, Baade could tell if the observer was pushing the East and West buttons to compensate. Good observers, like Milton Humason and Walter Baade, were magicians with the machines, with more tricks, bumps, and grinds than a burlesque queen in their repertoire of techniques to get the telescopes to behave. The tricks distracted from the primary task facing the observer, and as the size of an instrument reached the scale of the two-hundred, the idea of horsing a five-hundred-ton machine into position became absurd.

  Smith wasn’t an electrical engineer by training, but he was a veteran of many nights on telescopes, who understood what astronomers would want from a drive system. At a conference the Pasadena astronomers decided that the drive system should not have any periodic error of more than 1/10 of a second of arc (a second of arc is 1/60 of 1/60 of a degree, or 1/1,296,000 of a circle) for periods of five seconds or more. They also wanted automatic and manual controls of the dome and telescope, with repeater stations so the telescope could be controlled at the various foci.

  Their ideal was for the night assistant to dial in coordinates for the precise area of the sky the astronomer had selected, and for the control mechanism of the telescope to do the rest. The astronomers’ dream list included simple control panels at each observing station, with indicators of right ascension and declination, buttons for guiding and slewing the telescope, switches for adjusting the focus, and a telephone for communicating with the night assistant. Instead of horsing with the telescope or contorting himself into strange positions, the astronomer would use as much as possible of his precious time on the telescope for actual observing. Smith understood the wish list.

  Robert McMath, who had designed an operating and control system for telescopes in Michigan, and later for telescopes at the Lick Observatory and the new eighty-two-inch telescope of the McDonald Observatory in Texas, was invited to join the project as a consultant. “In the very nature of things,” he wrote,

  A project like the 200-inch telescope forces the engineer to extrapolate…. In this case, we are extrapolating many important items, such as the 200-inch mirror, the pedestal truss, the oil pad bearings, no polar axis defining bearings, the gimbal declination axis connections, the declination axis radial and thrust bearings, the polar axis torque tube, etc. Doubtless most of these items will prove satisfactory in service. Unfortunately, just one of them can spoil the job…. I again urge concentration of your available personnel on the problem of building the simplest possible telescope, considered as a whole.

  McMath particularly thought the plans for the electric drive system unnecessarily complex. The system he had designed took care of most corrections, except that it required that the observer manually change the rate of drive from time to time, based on what he observed in the guide scope eyepiece. His much simpler scheme, he pointed out, added “one-half of one percen
t more burden on the observer.” McMath’s control systems were good, but for this telescope the astronomers wanted even more.

  It wasn’t just the astronomers and engineers who had ideas for the control systems. In 1934 Max Mason had recommended that Hale and his colleagues study the “automatic curve-following mechanisms” which were being designed at MIT under Vannevar Bush. Hale had written to Bush, who thought his analog-computer mechanisms might be more accurate than any manual control of the telescope. The idea was to use photoelectric cells to track a guiding star and to trigger signals to control screws that would move the plate holder at the heart of the telescope in response to the apparent motion of the guide star. It was a superb idea, decades ahead of its time, but calculation showed that the field of view of the two-hundred-inch telescope was so narrow that the best of the guide stars would be magnitude 10 or 12, too faint for the photocells then available.

  Sandy McDowell, with his long years of experience supervising the construction and installation of naval gun turrets, also considered himself an expert on control mechanisms. He had worked for years with Hannibal Ford, whose small company on Long Island had developed pioneering servo control systems for big naval guns. McDowell wanted to use the Ford work in the telescope. The accuracy required by the drive mechanism for the telescope was orders of magnitude more demanding than the needs of naval guns—someone once calculated for publicity purposes that an error the size of a quarter at three miles would have been unacceptable—but to McDowell it was only an incremental difference. Ignoring the work of the Ford company, he said, was reinventing the wheel.

  On an early trip east, McDowell took Sinclair Smith with him to meet Hannibal Ford. Smith had spent his working life at Mount Wilson and had little experience dealing with large corporations or specialized defense contractors. McDowell insisted that no work take place on the drive controls until the Observatory Council had a proposal and estimate from Ford. Smith was given the job of conveying specifications to Hannibal Ford. Hannibal Ford and his company were not familiar with astronomical telescopes or equatorial mountings, so Smith faced a formidable task in explaining the requirements of pointing a telescope accurately to engineers accustomed to the much simpler task of moving a gun turret. The proposal and estimate from Ford were repeatedly delayed.