The Devil’s Observatory

The worst thing about Harqua Hala was the isolation.

Instruments on top, living quarters below. Observations from Harqua Hala helped identify changes in the sun’s energy output.

When Charles Abbott returned to the Smithsonian Astrophysical Observatory’s new Harqua Hala field station after a three-week absence, the place was “going to pot,” Abbott wrote to a colleague. Built atop Arizona’s tallest mountain, in the desert west of Phoenix, the adobe structure housed equipment to monitor the sun’s energy output. Abbott, the observatory’s director, hoped the readings would lead to better weather forecasts. But just months after it was built, several of the scientific instruments had been destroyed. The water tanks leaked, requiring Abbott and his assistant to lug water from a spring more than a mile down the mountain. One of the building’s walls buckled so severely that birds could fly in through the cracks. “Devil appears to have claimed everything,” Abbott wrote. “Have to exorcise him.”

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This story is a selection from the February-March issue of Air & Space magazine

But the devil never quite disappeared. Bad weather, the complexity of the observations, and the site’s extreme isolation made life difficult.

The isolation had been one of the site’s selling points for Abbott. The observatory had operated a sun-watching station atop Mount Wilson, overlooking Los Angeles, but the city’s rapid development stirred up dust and smoke that fogged the view. Abbott launched a search across the southwest for a better site, and quickly picked Harqua Hala. A team of local workers, using mules to carry most of the materials, built the station during the summer of 1920.

Windstorms there could reach gale force, and the summer monsoon brought heavy rains and lightning. Worse, high clouds and dust sometimes obscured the sun, ruining a day’s work. Nature provided other challenges: thick clouds of flies, scorpions and centipedes and other venomous things, bobcats that raided the facility’s hen house, and a rocky mountaintop that wore through shoe leather in weeks.

Perhaps the biggest problem, though, was the isolation. The nearest town, Wenden, was 16 miles away via trail and an almost impassable road. At first, the Harqua Hala folks had to walk or ride horses or mules, which took many hours each way. Later, they bought a second-hand Ford truck and built a metal garage at the foot of the trail to house it, cutting a few hours from the commute.

Initially, the station used a heliograph (sun-reflecting mirrors) to communicate with merchants in Wenden, who relayed the messages to Abbott in Washington, D.C. The system was a flop, though, as was a two-way radio, so the observatory strung telephone wires down the trail to connect to the Western Union lines beside the railroad track.

The residents found other ways to improve life at Harqua Hala. They built tanks to catch rainwater for showers, hauled up a Victrola and a rudimentary refrigerator, and erected tall aerials that picked up radio broadcasts from California and other states.

To monitor solar radiation, the observers used several instruments. One recorded the intensity of each wavelength of sunlight. Others measured heat from both the sun and the sky around it. It was complicated work, requiring exact timing and precise teamwork. The observers then spent several hours computing each day’s observations to prepare reports for Abbott. But in 1925, Abbott wrote that summer days atop Harqua Hala were just too hazy for good solar observations. Accordingly, operations were moved to Table Mountain, California, and Harqua Hala was abandoned—left to the wind, the flies, and the other unexorcised devils of the Arizona desert.

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