The Perfect Machine (7 page)

Hale excitedly pulled Clark aside. What, he asked, would it take to figure those disks into the objective lens for a large refractor? Clark gave him a rough estimate, and they discussed details of mounting, housing, and siting a telescope that large. From that day Hale was a man possessed. He had always dreamed of bigger and better instruments. Now he would build the biggest and best telescope in the world. He would site it in a fully equipped observatory, with laboratories right on the premises, with instruments like no others that had ever been built. All he needed, he calculated, was three hundred thousand dollars.

In the 1890s it was a considerable but not impossible sum. George Hale had grown up with wealth, and he knew there were many men in Chicago who could afford it. The Hale name gave him a ready introduction, and he wasn’t embarrassed to make his pitch for a telescope. For months he made the rounds of offices and homes of Chicago society, proposing his venture to anyone who would listen, his eyes sparkling with enthusiasm as he described his proposed observatory and what it could accomplish for science. Astronomy, he told anyone willing to listen, was ready for a revolution.

Hale did his best to explain that the old astronomy, men looking through telescopes to sketch what they saw, was exhausted. His proposal was something entirely different, an observatory equipped with the most modern laboratories and facilities, darkrooms, and spectroscopes. But no matter how enthusiastic his pitch, he found no takers. Times had changed, potential donors told him. Money was tough, the climate was wrong, this wasn’t the moment. For George Hale it was a good lesson in the vagaries of fund-raising.

Finally, on a tip from a mutual friend, Hale approached the streetcar magnate Charles Tyson Yerkes. Friends called him “Yerkes the Boodler.” The Boodler liked the idea of a telescope with his name on
it. When Hale promised that the telescope would be the largest in the world, bigger than the one at the famed Lick Observatory, Yerkes liked the idea enough to call in the press. “Here’s a million dollars,” he was quoted as saying in the
Chicago Tribune.
“If you want more, say so. You shall have all you need if you’ll only lick the Lick.”

Yerkes’ farsightedness and vision—always good terms for the donor of a telescope—dimmed considerably as the time came around to make good on his commitments. When he realized that the observatory would be at a remote site, and that much of the funding would go to laboratories and other facilities that were far less flashy and less likely to attract favorable publicity than the big telescope, Yerkes balked. Hale, relentless, cajoled Yerkes to follow through on his pledges, pressured contractors to get the work done, negotiated with local and university officials, and mediated between the perfectionists who would fiddle with the lenses and machines forever and the astronomers eager to use their new facility. The strain of the project, especially the battles with Yerkes, took their toll. Hale began suffering recurrent headaches, sometimes bad enough to keep him home in bed.

Friends, noticing his nervousness and anxiety, urged him to go easy. The optician John Brashear, who knew Hale from years of dealings on optical equipment, wrote, “You have a big responsibility on your hands … the only thing I beg you to look out for,
don’t overwork yourself.
… delegate all the work you can. Save yourself for that—which you can
do better than anyone can do for you.”

George Hale was twenty-four years old.

Despite the headaches Hale got the telescope and the observatory built. Yerkes, at what was then a remote site on the shores of Lake Geneva, eighty miles north of Chicago, emerged the most complete observatory in the world. The great forty-inch refractor, with its Clark lenses and Warner & Swasey mounting, was considered a sufficient engineering marvel to be exhibited at the 1892 World Exposition in Chicago.

In spite of routine winter temperatures at the observatory of-20°F, Hale attracted extraordinary optical and astronomical talent to Yerkes. For a period he could boast having the best observers and the best glass grinders in the world together under the domes and in the laboratories. Those who had seen the toll the construction took on George Hale urged him to settle down to the promising career of director of the great observatory. But even before Yerkes was dedicated, George Hale had a new idea.

In his own studies, with solar telescopes, Hale used a spectrograph to study the chemical composition of the sun. By identifying lines in the spectrogram that corresponded to the emission or absorption of particular materials, he could identify the presence of various elements in the sun—almost as accurately as if he had a sample of solar material in a laboratory. Knowing the chemical composition of the sun
and the solar atmosphere, astronomers could begin to ask what chemical or atomic processes were at work to create energy and light. What, Hale asked, if the same techniques that he applied to the sun could be applied to distant stars? It would be a whole new field, astrophysics, a discipline devoted to trying to determine what the stars and other celestial bodies outside our solar system were made of and what processes created the enormous energy in them. Once astronomers and physicists made some headway on those questions, they could take on the even grander field of cosmology, which tried to understand how the universe was put together, to discern the size, shape, structure, and origin of the cosmos.

The answers to those questions would demand telescopes far more powerful than even the great Lick and Yerkes instruments. Hale’s new dream was a huge new telescope, somewhere out in the clear air of California, where cloudless mountaintop skies provided night after night of good seeing, and where a facility could be all but immune to light pollution from urban illumination. The telescope Hale had in mind would not only be even bigger than the great Yerkes, but it would turn the circle from refractors, like the Lick and Yerkes telescopes, back to reflectors, like the telescope Newton had once used, relying on a mirror instead of a lens to gather and focus the faint light from distant objects.

The technology of refractors was temporarily exhausted. It might have been possible to cast and grind larger glass lenses than the forty-inch-diameter disks in the Yerkes refractor, but the sheer weight and fragility of the enormous glass disks, which can be supported only at the edges, and the engineering of the long tube, which must rigidly hold and point the lenses, had reached their limits. In France a refractor with lenses close to sixty inches in diameter was built and displayed at the Paris Exhibition of 1900, but it was not successful as a telescope. Even if a bigger refractor could be built, a reflector had many arguments in its favor for astrophysics research.

The light of a star or other distant object goes through the objective lens of a refractor. Because light of various colors bends, or refracts, differently as it goes through the glass, a refractor is not achromatic; the lens forms a series of images of different wavelengths. Only some of these effects can be corrected. A reflector, by using the surface of a mirror to focus the light, avoids this problem. The optics of a big reflector are also easier to grind and polish. Instead of four surfaces of glass to grind, figure, and polish, two on each of the elements that are sandwiched to make up an objective lens, a reflector requires only a single optical surface, the face of the primary mirror.

Finally, the physical mounting of a refractor, with its long, rigid tube supporting the objective lens at one end and an eyepiece or instrument at the other, presents difficult engineering problems as the instrument gets larger. The long tube must be balanced on its equatorial
mounting, and for the telescope to reach all areas of the sky, the mounting must be on a tall pillar. When the telescope is pointed toward targets of low altitude, the eyepiece is high off the floor, out of reach of the observer or his cameras. At Lick and Yerkes this problem was solved by having the entire floor of the observatory rise and fall around the fixed telescope mounting pillar. An early accident with the moving floor was another hint that refractors were approaching their technical limits.

Because the light can be bounced back up the tube from the primary mirror to a secondary mirror, in effect folding the focal path of the telescope, a reflector can be built with a relatively short tube, short enough in most instances for the telescope to be mounted in a movable fork with its pivot point close to the primary mirror. Without the weight of a heavy lens to support at the far end of the tube, the reflector can use an open tube, resulting in a lighter structure and greatly simplifying the construction of the instrument.

The reflector is also more versatile than a refractor. The eyepiece, or more typically for a large instrument, the cameras or spectrograph, of a reflector can be mounted at one side of the high end of the tube, in what is called the Newtonian position, after Newton’s early design. The light from the primary mirror is deflected to the Newtonian focus with a small diagonal mirror suspended inside the telescope. It is also possible to bounce the light from a secondary mirror back through a hole in the center of the main mirror so that cameras and other instruments can be mounted at the base, or supported end of the tube at what is known as the Cassegrain focus. With additional mirrors, the light can be directed to a fixed Coudé position of extreme focal length in a separate temperature and humidity-controlled room. Finally, if the telescope is big enough, the light can be deflected through the hubs of the declination axis, to Nasmyth foci on either side of the telescope. The different foci, each with different focal lengths, add up to increased versatility for the reflector.

When George Hale began thinking about a new telescope, the arguments for a reflector weren’t only theoretical. In 1895, the same year that the lenses for the great refractor at Yerkes were finally finished, Edward Crossley of Halifax, England, presented the thirty-six-inch Calver-Common reflector to the Lick Observatory. The new reflector was overshadowed in publicity by the larger telescope at Yerkes. While Yerkes’ telescope dominated the press, the mirror of what came to be known as the Crossley reflector was quietly refigured and a new mounting built for photographic work. Keeler, the director of the Lick Observatory, used the Crossley, the first large reflector in the United States, to reveal an immense number of spiral nebulae that had never before been recorded.

The Crossley was an awkward telescope to use, with a stiff mount that required a kick from time to time to get it to behave, but so many
spiral nebulae could be photographed, or even seen visually with the telescope, that it raised disturbing cosmological questions. Heber Curtis’s continuation of this study provided the background for his contributions to the great debate in Washington.

Hale kept abreast of the work with the Crossley reflector at Lick. The incentive of following up on that work, and a program to extend the detailed spectrographic studies Hale had made of the sun to distant stars, was a compelling agenda for a big reflector. And when the headstrong young director of Yerkes Observatory got an idea in his head, there was no stopping him. Before the forty-inch refractor at the Yerkes Observatory was dedicated, Hale persuaded his father to contribute the funds to have a sixty-inch glass blank—the largest piece of glass the French foundries could mold in a single pour—cast for a giant reflector. William Hale made it clear that his gift was seed money; he would pay for the glass blank and nothing more. It would be up to George to find the money elsewhere to have mirror and other optical surfaces ground, to mount the telescope, and to build an observatory. George accepted the challenge.

The Saint-Gobain glassworks in France successfully poured the disk. It was annealed—heated, then gradually cooled over a period of months to avoid strains in the glass from rapid cooling—and shipped to Yerkes. Although funding to complete the project was nowhere in sight, Hale had a colleague at Yerkes, George W. Ritchey, begin grinding the mirror.

Ritchey had little academic training, but he had built several telescopes as a student at the University of Cincinnati, and in 1888 he set up a laboratory at home in Chicago before coming to work for Hale at the Kenwood Observatory. From Kenwood he moved on with Hale to Yerkes. Among astronomers Ritchey was known for his fierce concentration and what one colleague called “the temperament of an artist and a thousand prima donnas.” Ritchey would sometimes spend hours on a single photograph, setting and resetting the focus until it was exactly right, waiting for the perfect seeing conditions, then concentrating so intensely on guiding the fine motions of the telescope that an explosion nearby would not have distracted him. The resulting photograph would be an artistic masterpiece—except when Ritchey, lost in his concentration, neglected to record the date, time, or sky conditions, so that the plate was useless for scientific purposes.

Though hard on colleagues, Ritchey’s perfectionism was ideal in the optics laboratory. He was delighted to seal himself off for hours, even days, at a time, allowing no one near his project, ruling over his domain as an absolute tyrant while he patiently ground, then polished the disk.

While Ritchey began grinding the sixty-inch disk at Yerkes to the optical shape the future telescope would require, George Hale pounded the pavements again, making his pitch for funds to build the
sixty-inch telescope. In 1901 he persuaded John D. Rockefeller to visit Yerkes Observatory. The usual show for VIPs was to mount an eyepiece on the telescope and point it to familiar objects for the entertainment and enlightenment of the visitor, but clouds covered the sky most of the day and evening of Rockefeller’s visit. Instead Hale took Rockefeller to the optical laboratory where Ritchey was working on the sixty-inch mirror. Ritchey showed off the procedures and tests used to figure and test a mirror. In one test Ritchey put his finger on the glass surface for a minute, then demonstrated that the distortion of the surface from the heat of his finger could actually be measured. Rockefeller was fascinated by the sensitivity of the test and asked to see it again. But interest wasn’t commitment, and Rockefeller wasn’t willing to fund Hale’s telescope. Nor, it appeared, was anyone else. Hale ran out of pavement to pound. The days of big telescope bequests seemed to be over.