The Perfect Machine (40 page)

Adams, Anderson, Hale, and Tracey found the Nate Harrison Grade reminiscent of the old toll road on Mount Wilson. From the grade up over the top and down the other side to the Oak Grove Ranger Station, they looked at potential sites for an observatory, finally settling at a place near the center of the plateau, at an altitude of 5,500 feet. From the site they could see north to the San Bernardino
peaks and south as far as the Coronado Islands off the coast south of San Diego. At night, the loom of light of Los Angeles was barely visible on the horizon. San Diego, though closer, was also scarcely visible. It was hard to imagine that the light of either city would ever be a problem. The Caltech geologists came back to map the character of the terrain and the underlying geological structure and to determine the exact latitude of the site. The engineers would need the latitude for the final design of the equatorial telescope mounting.

If there had been any doubts about Palomar as a site before that last trip, there were none after. The Observatory Council agreed that the telescope would be sited at Palomar and gave Henry Robinson the task of negotiating to buy up the needed land. Word of the plans got out to the ranchers on the mountain before Robinson made his initial approach. Mendenhall in particular, who had heard about the budget of the project, was set to hold out for an enormous sum, despite the depression plunge in land prices.

In 1931 forty square miles of land next to the site, including some private land, had been declared the Cleveland National Forest, part of an effort by the National Forest Service to control forest fires. Caltech wanted a portion of the National Forest land for the observatory. Anderson and Robinson explained their plans, and Guerdon Ellis, the forest supervisor, was enthusiastic about Caltech’s proposal: “Inasmuch as I can conceive of no higher use to be made of these 40 acres of land than that which you request, the use of the land is practically assured the Observatory forever.”

The bargaining with the local landowners went on all summer. San Diego, eager to have the research facility in its county, agreed to build an all-weather road up the slope to the site of the observatory. The final deal was signed on September 21, in the Beeches’ weather-beaten cabin on a slope of the French Valley. Five men, representing Caltech, the ranchers, and San Diego County, sat around an old-fashioned wooden table. An early fall storm was raging outside, so they worked by the light of a kerosene lamp, until the lamp ran dry and they had to use candles.

The agreement, signed at 3:00 A.M., provided that when Kenneth and William Beech were handed a check for $12,000 that was being held in escrow in San Diego, 120 acres from different ranches would be transferred to Caltech. The government would transfer an additional 40 acres, making the observatory site a total of 160 acres. San Diego County would begin work on a road up to the site at the earliest possible time. The ranchers had already agreed between themselves that the Mendenhalls would continue to have grazing rights on the mountain. Cave C. Couts, a descendant of an early pioneer on the mountain, and the Beeches, provided the rest of the land.

The San Diego newspapers lapped up the story, from the storms
and kerosene lamps to the announcement that “with the closing of the deal Southern California was assured a scientific institution which will comprise one of the wonders of the world,” By the end of the year a Civilian Conservation Corps (CCC) camp had been built in the Doane Valley, west of the proposed observatory site, to house the workers for the County Road. San Diego had already named the road the Highway to the Stars, and proposed changing the name of the mountain to San Diego Mountain. Outraged citizens wrote poems to the Oceanside newspapers demanding that the old name stay. John Anderson, on behalf of Caltech, pointed out that since Palomar was the name in use on topographic maps, changing it would create confusion. San Diego gave in and agreed to leave the name alone. Instead they started printing new publicity maps for the county, with the site of the observatory prominently marked.

In 1934 there was still no design for the telescope, only a collection of specifications, ideas, and requirements.

From the earliest talk about a big telescope, Pease had favored a fork mount, like the mounting on the sixty-inch telescope. The advantage of the fork mount was simplicity: Because the tube of the telescope was held only at one end, the fork permitted the telescope to point to all of the sky overhead. Pease had designed most of the one-hundred-inch telescope. His early drawings and model were the departure point for the project, and the models that were shown at the National Academy of Sciences and brought out for curious reporters were based on his drawings and early models. As late as February 1931, when a reporter asked about the design of the telescope, Hale answered that “the fork type [mount]… seems the most promising.”

But there were problems with a fork mount. If the telescope tube were supported only at one end, while the other end carried the weight of auxiliary mirrors, mechanisms to interchange the mirrors, and a cage big enough for an astronomer—achieving the required rigidity in the tube became an impossible engineering task. At the tolerances required for the telescope, even a massive tube of steel girders behaves like a hollow noodle cooked
al dente.
Hold it at one end, and the other end droops. Making the forks long enough to support the tube in the middle would substitute drooping forks for a drooping tube. The fork mount also presented problems for the use of some of the alternate foci astronomers had requested, and the concentration of the entire weight of the telescope on a single set of bearings troubled the engineers.

There were two alternatives, which pivoted the tube in the middle. Early on, Hale had urged consideration of the so-called “German” mount, made popular by Zeiss in the telescopes they had designed and built. The German mount—also called the “Victoria” mount after a 72-inch telescope in British Columbia—put the tube of the telescope on
an extended shaft, with a counterweight on the other end of the shaft. It was popular for small telescopes, but a counterweight would effectively double the load on the bearings for the tube of the telescope, making the mount impractical for a telescope as large as the two-hundred-inch. The other possibility was a form of yoke mount like the one on the one-hundred-inch telescope. The yoke could be supported at both ends, dividing the bearing load for the telescope. The disadvantage of the yoke was that it blocked the tube of the telescope from dipping low enough to view the North Polar region of the sky. Hubble and Humason were already chafing at the inability of the one-hundred-inch telescope to photograph or take spectra of galaxies in the north polar region. No one wanted to build another telescope with that limitation.

Russell Porter, who had never before worked on a large telescope, had played with some maverick ideas. In the telescopes he had designed for the Stellafane amateur astronomy center, and in drawings he had done for the “Amateur Telescope Maker” column of
Scientific American,
Porter had come up with telescope designs unlike anything anyone had ever seen before. Some telescopes kept the observer in a fixed location indoors, with the moving parts of the telescope outdoors. One design, his Garden Telescope, looked like a decorative sundial, with parts of the mounting done up in Art Nouveau scrolls.

As early as 1918 Porter proposed a split ring for the north end of a yoke. The split ring would allow the tube of the telescope to be lowered enough to view the polar region, while still dividing the weight of the telescope between bearings at the two ends of the yoke. Porter patented the idea in 1918, before he began work on the two-hundred-inch telescope. When he got to Pasadena, he began sketching ideas for a mounting for the two-hundred-inch telescope, using variations of his split ring.

Porter, who was older than the others, and whose hearing difficulties left him the odd man out at meetings, had a hard time convincing people that his ideas deserved attention. He was an outsider, without the formal academic credentials and big-telescope experience of the Mount Wilson and Caltech staff on the project. He had also been brought in by Hale at what others in the project considered a too-high salary. Porter’s initial appointment was for a year, and his official design assignments were small projects like the telescope used to measure the seeing at sites, and architectural details of the Astrophysics Laboratory and Optics Lab on the Caltech campus. Frustrated, Porter threatened to go back to Vermont. Hale encouraged him to stay on. When others ignored Porter, Hale would ask him privately to sketch up various designs. Porter’s memos were pencil sketches and hand printed notes rather than the typed memorandums with eight carbon copies that characterized most of the official communications of the project.

By 1934 the chief design question was whether the telescope should have a fork mount or some variation of the split-ring design. Porter’s sketches, amalgams of his own ideas and the suggestions from brainstorming sessions, gradually evolved into a giant
or horseshoe, with the outside of the horseshoe serving as a bearing surface to support the telescope as it turned in right ascension to match the motion of the earth. Francis Pease, who probably came up with the idea independently, had used a form of split ring in one early sketch he did of the three-hundred-inch telescope that had been talked about in 1921. As the design group settled on the horseshoe, Pease was generally credited with the design. Porter, angry that he was not given proper credit, became even more isolated from the others working on the telescope.

With the main design agreed on, it was time to move from sketches to engineering drawings. From the earliest days Hale and Anderson had turned to the Caltech engineers for advice and designs. Theodor von Karmann in aeronautical engineering and Romeo Martel in mechanical engineering, stars of their departments, and the mathematical physicists Harry Bateman and Paul Epstein had all had been consulted on the final design for the ribbed back of the glass disks. They were asked to recommend both personnel and ideas for the telescope mounting.

Romeo Martel recommended a young engineer named Mark Serrurier, who had come to work for Caltech in November 1932. Engineering jobs were tough to find in 1932. The aircraft companies were at a standstill, and public authorities were cutting back to limited maintenance programs. The design program for the telescope soon had its pick of young graduates, eager for the chance to work on a major project. Serrurier had been eager to work in Southern California. The movie industry would have been his first choice, but he was willing to take any work he could get. He did some consulting on the new Golden Gate Bridge in San Francisco. The new telescope seemed an exciting project. Serrurier was too young to realize how impossible the assignment was.

Even with the fast focal ratio of f/3.3, the main telescope tube for the two-hundred-inch telescope would be fifty-seven feet long and weigh close to 250,000 pounds. Early in the design process Hale wrote: “The first point is to study the tube, which should be
extremely
rigid and capable of carrying … the heaviest attachments without injurious flexure.” Dr. Ross, the designer of the corrective lens for the prime focus of the telescope, calculated that effective use of the lens required that it be fixed within 0.040 inch (approximately one millimeter) of the optical path of the telescope, and that the position of the lens could not move more than 0.020 inch during an exposure. What this meant in engineering terms was that for the duration of a photographic exposure,
typically one hour, the alignment of the tiny lens and a mirror fifty-seven feet away could not vary by more than a half-millimeter—all while the enormous telescope tube that held both in alignment was moving to track an object. To complicate the design, the light path for the Coudé focus required a slit on one side of the telescope tube, so the light could be bounced to an auxiliary mirror.

In his engineering courses or his work on the Golden Gate Bridge, Serrurier had been given design problems for skyscraper and bridge frames that were allowed to sway by feet. Quick calculations showed that the truss sections and cross-bracing in his engineering texts wouldn’t work for the telescope tube. Nor would the massive riveted-girder construction that had been used for the sixty- and one-hundred-inch telescopes. If the telescope tube were massive enough to hold its alignment by brute force, the ends would droop under their own weight, and the telescope would be so massive that it would be impossible to design bearings and a drive mechanism that could move it smoothly.

Day after day Serrurier sat in his office in the basement of the astrophysics building, playing with rulers and pencils to model the stresses on a tube structure. No idea worked, until one day Martel came by and suggested that the tube didn’t really have to be so rigid that the mirror and the lens at the focus would never move in relation to one another; what mattered was that they remain
aligned
within a half-millimeter. Imagine, Martel suggested, a tube that sags at both ends, but in such a way that the ends remain precisely parallel to one another. The lens at one end would still be perfectly aligned with the mirror at the other. In engineering terms Martel had switched the problem from flexible stress to sheer stress. Serrurier listened, sketched the idea on paper, then went back to work with his pencils and rulers. The solution wasn’t immediately obvious, but at least he was off dead center.