he fails, he fails
Utterly.
—ALFRED NOYES, WATCHERS OF THE NIGHT
It was 1917 before the telescope was ready for first light.
The weather was clear and cool when the group left Pasadena for the drive up to Mount Wilson, the kind of November evening in Southern California that condenses enough moisture to require windshield wipers on a clear evening. Pasadena is a flat city, with streets laid out in a rectangular grid. Were it not for the palm trees that line the main streets, the stucco exterior walls, and red tile roofs, it could pass for a midwestern city.
The mountains arise abruptly at the northern edge of the city. As the party drove up the rugged nine-mile path from the base of Mount Wilson, through patches of scrub oak, sagebrush, and black-cone fir, layers of fog closed in, first scattered, and then so dense that driving was difficult. Only at the summit, at 5,700 feet, did they break through the fog that obscured the light of the sprawling Los Angeles basin below.
The city’s pain was the astronomers’ gain: The frequent fogs below the summit, and the inversion layer that trapped pollutants in the Los Angeles Basin, were a blessing on Mount Wilson. The fog scattered and occluded the light of the city below, and the inversion stabilized the atmosphere. From the peak the sky overhead was filled with stars, pinpoints in a celestial dome of black velvet. The stillness of the atmosphere left the star images stable, without the twinkle that inspires poets and frustrates astronomers. Mount Wilson has among the best seeing of any observatory site in the world.
That cold November night in 1917, twenty men walked across the narrow wooden drawbridge to the one-hundred-inch telescope. The dome was immense, dwarfing the dome of the sixty-inch telescope in the distance. A table had been set up so each of them could sign the logbook that W. P. Hoge, night assistant on the sixty-inch telescope, used to record the evening’s events.
The great telescope loomed above them, a seventy-five-foot-high erector set of riveted black steel girders and huge brass gears. An astronomical telescope is an impossible combination of the scale of a battleship and the precision of a microscope. The heart of the telescope was a fraction of an ounce of silver, the coating of the great mirror that had been polished to as perfect an optical shape as the opticians could achieve. Everything else—the whole huge structure of girders, gears, bearings, and drive mechanisms—was there to cradle and aim that ounce of silver.
The mounting had been fabricated by the Fore River Shipbuilding Company in Quincy, Massachusetts—a division of Bethlehem Steel more accustomed to building naval gun turrets than precision optical devices. Sections of the telescope tube were so large they had to be shipped around Cape Horn to Los Angeles Harbor. Assembled, the instrument weighed one hundred tons. The clock mechanism alone required a ton of bronze castings, one and a half tons of iron castings, a two-ton driving weight, a seventeen-foot driving wheel, and a maze of hand-machined gears, each wider than a man’s reach. Altogether the telescope, dome, and shutters needed thirty electric motors to move them.
The great one-hundred-inch-diameter mirror was mounted at the bottom of an open tube of riveted steel, eleven feet in diameter and more than forty feet long. The tube pivoted at its center in a heavy steel yoke; motors turning hand-machined gears rotated the tube on the pivots to direct the telescope to objects higher or lower in declination. The steel yoke was suspended at each end on huge floats in mercury bearings and precisely aligned with the axis of the earth, so that as the telescope turned synchronously with rotation of the earth, the heavens would seem to stand still. The massive yoke was designed by Francis Pease, an astronomer at the observatory, in the so-called English style, with the north end closed. The price of the great rigiditywas that the
Utterly.
—ALFRED NOYES, WATCHERS OF THE NIGHT
It was 1917 before the telescope was ready for first light.
The weather was clear and cool when the group left Pasadena for the drive up to Mount Wilson, the kind of November evening in Southern California that condenses enough moisture to require windshield wipers on a clear evening. Pasadena is a flat city, with streets laid out in a rectangular grid. Were it not for the palm trees that line the main streets, the stucco exterior walls, and red tile roofs, it could pass for a midwestern city.
The mountains arise abruptly at the northern edge of the city. As the party drove up the rugged nine-mile path from the base of Mount Wilson, through patches of scrub oak, sagebrush, and black-cone fir, layers of fog closed in, first scattered, and then so dense that driving was difficult. Only at the summit, at 5,700 feet, did they break through the fog that obscured the light of the sprawling Los Angeles basin below.
The city’s pain was the astronomers’ gain: The frequent fogs below the summit, and the inversion layer that trapped pollutants in the Los Angeles Basin, were a blessing on Mount Wilson. The fog scattered and occluded the light of the city below, and the inversion stabilized the atmosphere. From the peak the sky overhead was filled with stars, pinpoints in a celestial dome of black velvet. The stillness of the atmosphere left the star images stable, without the twinkle that inspires poets and frustrates astronomers. Mount Wilson has among the best seeing of any observatory site in the world.
That cold November night in 1917, twenty men walked across the narrow wooden drawbridge to the one-hundred-inch telescope. The dome was immense, dwarfing the dome of the sixty-inch telescope in the distance. A table had been set up so each of them could sign the logbook that W. P. Hoge, night assistant on the sixty-inch telescope, used to record the evening’s events.
The great telescope loomed above them, a seventy-five-foot-high erector set of riveted black steel girders and huge brass gears. An astronomical telescope is an impossible combination of the scale of a battleship and the precision of a microscope. The heart of the telescope was a fraction of an ounce of silver, the coating of the great mirror that had been polished to as perfect an optical shape as the opticians could achieve. Everything else—the whole huge structure of girders, gears, bearings, and drive mechanisms—was there to cradle and aim that ounce of silver.
The mounting had been fabricated by the Fore River Shipbuilding Company in Quincy, Massachusetts—a division of Bethlehem Steel more accustomed to building naval gun turrets than precision optical devices. Sections of the telescope tube were so large they had to be shipped around Cape Horn to Los Angeles Harbor. Assembled, the instrument weighed one hundred tons. The clock mechanism alone required a ton of bronze castings, one and a half tons of iron castings, a two-ton driving weight, a seventeen-foot driving wheel, and a maze of hand-machined gears, each wider than a man’s reach. Altogether the telescope, dome, and shutters needed thirty electric motors to move them.
The great one-hundred-inch-diameter mirror was mounted at the bottom of an open tube of riveted steel, eleven feet in diameter and more than forty feet long. The tube pivoted at its center in a heavy steel yoke; motors turning hand-machined gears rotated the tube on the pivots to direct the telescope to objects higher or lower in declination. The steel yoke was suspended at each end on huge floats in mercury bearings and precisely aligned with the axis of the earth, so that as the telescope turned synchronously with rotation of the earth, the heavens would seem to stand still. The massive yoke was designed by Francis Pease, an astronomer at the observatory, in the so-called English style, with the north end closed. The price of the great rigiditywas that the
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