The Day We Found the Universe - Marcia Bartusiak [121]
Humason was not too happy at first upon hearing of his new assignment. Hubble had come home from Leiden quite excited and quickly suggested to Humason that he try to obtain a galaxy redshift that was not yet known. But the prism on the 100-inch spectrograph had started to yellow, and the photographic plates then on hand were considerably slow-acting for such work. Humason knew it would take several nights to get a decent spectrum. “I didn't feel much enthusiasm about these long exposures,” he later recalled. “But [Hubble] kept at me and encouraged me.” Hubble was after fainter and fainter objects, the ones too distant for Slipher to have studied with his smaller telescope, and some were low on the southern sky. “To get these,” said Humason, “you had to climb onto the 100 inch and sit on the iron frame during the long winter nights, which was extremely cold and uncomfortable.” For hours on end, through the freezing night, he would have to keep his guide star on the center of the cross wires, to make sure his image remained sure and steady. “The eye-strain, the monotony, the constant awareness—it was a test of endurance,” he said. But Humason's unusual entrée into astronomy offered him superb preparation for this arduous undertaking. He was accustomed to hard work.
Born in Minnesota in 1891, Humason as a boy moved to the West Coast with his family and one summer as a teenager enjoyed a camping holiday on Mount Wilson. He fell in love with the mountain and soon dropped out of grammar school to work as a bellboy and handyman at the newly opened Mount Wilson hotel, a popular resort spot for local residents. He washed dishes, corralled the horses, and shingled the cottages. Once the 60-inch telescope was under construction, he drove the mule trains that took the equipment, piece by piece, up the rugged path to the top of the peak. When a mountain lion was found feasting on a prized goat in the area, Humason tracked the animal down and shot him between the eyes with a .22-caliber rifle. Several years after Humason married the daughter of the observatory's chief engineer, his father-in-law arranged for him to work as the observatory's janitor. Gradually he was allowed to help the astronomers as a night assistant and over time won their respect and trust in making observations on his own, despite his eighth-grade education and lack of formal training in astronomy. Seth Nicholson took the young man under his wing and taught him some mathematics; Shapley mentored him as well. With his round face and round eyeglasses, the quiet and self-effacing Humason came to look like an academic. In 1920 he was promoted to a staff position in the photography department and two years later moved up to assistant astronomer. Known for his patience and conscientious attention to detail, he became especially skilled at taking long photographic or spectroscopic exposures of the most faint celestial objects. A likable fellow and an inveterate gambler, he relieved the pent-up tension from this grinding work by playing poker with the other night assistants and shop workers. If his schedule allowed, he'd catch the late-afternoon horse races at the nearby Santa Anita racetrack, taking any astronomer who wanted to go with him.
Over time, Humason was even put in charge of arranging telescope time. Sharing Hubble's strong loyalty for the Republican Party, Humason tried to get as many Democrat observers as possible on the mountain, away from the polls, on election days. Solar astronomer Nicholson, a staunch Democrat, evened the score by making sure only Republicans were scheduled on the solar telescopes at the same time. Hubble, whose status could never be threatened by Humason's humbler origins, got along fine with his devoted junior partner.
Milton Humason at Mount Wilson
(Courtesy of AIP Emilio Segrè Visual Archives)
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By 1929 Hubble had determined the distances to twenty-four galaxies (including the Small and Large Magellanic Clouds), the most remote then judged to reside some 6 million light-years away. He accomplished this feat by establishing