Palomar Observatory: Hale (Part 9)

To start with this “Palomar Observatory” series at the beginning, click HERE.

George Ellery Hale
George Ellery Hale

We’ve expended a fair amount of words describing George Ellery Hale’s penchant for building the world’s largest telescope; after all, he did it on four separate occasions. If his legacy were to rest solely on his efforts to build these technical masterpieces—each device gave humanity the ability to peer deeper and more perceptively into the cosmos—Hale would be considered a giant of science in general and astronomy in particular. He’d arguably be remembered as the originating force behind Big Science, the twentieth-century narrative that has given the world remarkable insight into nature, the universe, and reality.

But building telescopes wasn’t the only thing Hale was doing; he was also using them. The singular achievement of Hale’s scientific career was coming about just as he was finishing the 60-inch telescope and beginning work on the 100-inch. In 1908, Hale published a paper entitled “On the Probable Existence of a Magnetic Field in Sun-spots.” Like any good scientist, Hale built his case for the presence of magnetic fields on the Sun on the work of others: J. J. Thompson’s work on electrons emitted by hot bodies and the Zeeman effect, which describes the splitting of emission spectra in the presence of a magnetic field. In a 1999 article reviewing Hale’s discovery, astronomer John Harvey wrote, “Only a handful of scientists have shown that a fundamental force of nature exists beyond Earth. George Ellery Hale, an unquestioned giant of twentieth-century astrophysics, is one of those few people, by virtue of his discovery of magnetic fields in sunspots.”

Of course, all the while he was carrying out groundbreaking research, Hale continued to make plans for building for the next world’s largest telescope: 100-inches in diameter. Its patron was Los Angeles businessman John D. Hooker, a nineteenth-century industrialist who eventually became president of the Western Union Oil Company. Hooker had long been interested in science-oriented philanthropy; he was one of the founders the California Academy of Science. Funding the research and development of the 100-inch mirror for Hale’s next telescope was a logical outcome for Hooker’s interests and efforts.

Model of Hale Telescope inside the Dome
Model of Hale Telescope inside the Dome

The heart of a reflecting telescope is the glass that is used in the mirror blank. Once again, Hale turned to the house of Saint-Gobain, master glass workers located in Paris, France, for his new mirror. Saint-Gobain had never created an optical instrument of this size. No one had. There were industrial limits—based on the size of the buckets that were used to carry the molten glass—on the amount of glass that the wizards of Saint-Gobain could pour into the mold. These limits meant that the mirror had to be poured in three distinct layers, one on top of another. Pouring this much glass posed an enormous risk, not just for the final product, but also to the men handling the ladles of superheated, liquid glass. Injuries resulted, including lost limbs, and in the end, the results would, at first glance, appear to be a deeply flawed piece of glass.

After more than a year of cooling, the mirror blank—more than eight feet across and ensconced in a fourteen-foot-diameter, purpose-built metal cradle—made its way across the ocean and to the United States. In her biography of Hale, Explorer of the Universe, author Helen Wright said, “Hale received news of the successful casting of a 100-inch disk. Less than three months later, the great disk, the size of a small room, arrived in Hoboken aboard the steamer St. Andrew. The New York Press called it the single most valuable piece of merchandise ever to cross the Atlantic.”

When it arrived in Pasadena, George W. Ritchey, Hale’s master optician, despaired. Removed from its cradle, the mirror blank looked like nothing more than a three-layer glass cake. The mirror blank was in disastrous shape. Riddled with bubbles and voids, Ritchey pronounced that the glass was unusable. Ritchey believed that he’d never be able to grind it into an astronomical instrument. The arrival of the mirror signaled the start of a very dark period in Hale’s personal and professional life.

We’ll take up with a look at that dark time in Hale’s life in a future post, as we wrap up this series on one of the most ambitious, accomplished, quirky men of science.

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