In 1925 scientists sought to use airplanes and an airship as aerial platforms to observe and photograph a total eclipse of the sun.
When the airship USS Los Angeles headed toward the Atlantic Ocean from its base at Lakehurst, N.J., on the frigid morning of January 24, 1925, it was chasing a shadow. The U.S. Navy airship carried seven scientists and 500 pounds of telescopes and other skywatching gear to observe a total solar eclipse. The plan called for the dirigible to station itself near the center of the moon’s shadow as the shadow raced across New York and Connecticut and out to sea. Astronomers counted on Los Angeles to provide a stable platform for observing the rare spectacle.
Los Angeles wasn’t alone in the shadowy skies of the Northeast. A fleet of 25 airplanes—reportedly the largest military aviation operation since World War I—took off from the Army Air Service’s Mitchel Field on Long Island, carrying astronomers, reporters, radio broadcasters, and still and motion-picture photographers.
The shadow passed directly across New York City just after 9 a.m., making it perhaps the most-viewed solar eclipse in history. Astronomers predicted that the path of totality—the zone where the moon completely covers the sun—would bisect Manhattan Island, covering everything north of about 83rd Street (they were off by 13 blocks).
Despite bitter cold, with temperatures in the single digits, millions of New Yorkers packed the streets, parks and hillsides. They “wrapped themselves tighter in shawls and blankets, stamped their feet, beat their hands and exhaled clouds of fog,” The New York Times reported. Men and boys hawked bits of exposed film, smoked glass and other eye protection, sternly warning of the “dangers of going blind” for those who went without.
Astronomers staked out positions all along the eclipse path, from Minnesota across the Great Lakes to the East Coast. Experience showed, however, that Mother Nature didn’t always cooperate with eclipse viewing, so scientists turned to aviation as an insurance policy against clouds or fog.
Navy aircraft had carried some astronomers and their cameras aloft during an eclipse in 1923. Although the results were disappointing, the U.S. Naval Observatory (USNO) wanted to try again, using winged aircraft and both of the Navy’s dirigibles, Los Angeles and Shenandoah. The helium supply was too low to support both airships, however, so the Navy assigned the job to Los Angeles. It couldn’t fly as high as the airplanes, but it could carry more people and equipment, and astronomers hoped its great size and slower speed would make it a steadier platform for observations.
Los Angeles had been built by Germany’s Zeppelin company. It arrived at Lakehurst in October 1924 and was designated ZR-3 by the Navy. First Lady Grace Coolidge christened the ship on November 25 at Naval Air Station Anacostia in Washington, D.C. The behemoth measured more than 650 feet and was powered by five 400-hp Maybach V-12 engines, which produced a cruising speed of about 48 knots and a maximum speed of 65 knots. It was lofted by 2.7 million cubic feet of helium, held in 14 cells.
Winter threatened to keep both Los Angeles and the airplanes grounded, though. “It was not clouds, but wind that caused the immediate trouble,” according to an official USNO report. A powerful cold front blew through the area the day before the eclipse, bringing the coldest weather of the season and strong northwest winds.
Preparations for the airship’s departure were scheduled to begin at 3 a.m. on January 24, but gusty winds kept Los Angeles in its hangar. Conditions had calmed enough by 4 a.m. to board the 42 officers, crew and expedition members while still inside the hangar, although 11 men were asked to disembark and reboard later. The hangar doors finally opened and the 300-man ground crew began wrestling the airship outside.
“As it emerged into the outside air, it began to perform somewhat in the manner of a balky mule,” the USNO report stated, “and would carry all the men with a sudden rush many feet swiftly in one direction and suddenly in another. In the meantime the would-be passengers were trying to follow its eccentric movements, to avoid collisions with men on the guy ropes, to keep from falling over the frozen hummocks of the field or from slipping down on the icy spots. One sudden gust carried the ship many feet up into the air, men hanging to the ropes in what seemed a desperate predicament.” Ground and air crews brought the giant beast under control, however, and it departed at 5:22 a.m.
The expedition was directed by 54-year-old Captain Edwin Taylor Pollock, superintendent of the Naval Observatory and a veteran of the Spanish-American War and World War I. Los Angeles was under the command of the ship’s executive officer, 37-year-old Commander Jacob H. Klein Jr., who had been awarded the Navy Cross for his service as a World War I destroyer skipper. Klein was one of four American officers to fly aboard Los Angeles during its trip from Germany.
As the airship droned northeastward, the fleet of aircraft departed Mitchel Field, home of the 9th Observation Group. In all, 35 planes, including more than a dozen assigned from other bases, were on hand for the exercise, although frozen engines kept 10 of them on the ground. The participating aircraft included de Havilland DH-4Bs and Martin MB-1 bombers.
Mitchel Field’s commanding officer, Major William N. Hensley Jr.—the first American to fly nonstop across the Atlantic, aboard a British airship in 1919—had issued special orders to all pilots the day before. “Mitchel Field was so thickly covered with planes that traffic rules had to be drawn up,” the Times explained, “and a set of orders was issued regulating the use of the air in order to prevent collisions in the swarming skies during the darkness of the total eclipse.”
The airplanes began taking off at 7 a.m. and split into multiple groups—one headed for New Haven, Conn., another for Greenport on Long Island. “One of the oldest sciences, astronomy, collaborated with one of the newest, aeronautics, today in adding to the accumulated wisdom of the ages,” wrote an Associated Press reporter. “Uncle Sam’s army air service abandoned the pursuit of war lore to work with scientists, lifting them two or three miles above the earth’s crust that they might better record data of the total solar eclipse.”
One scientist, 25-year-old Willem Jacob Luyten of Harvard College Observatory, pulled double duty, acting as a reporter for the Times. He flew with Major Davenport Johnson, a squadron commander at Mitchel Field who had been awarded the Silver Star for his service in France during the war.
Luyten and Johnson were on station south of Waterbury, Conn., at an altitude of 15,100 feet when the sky went dark at 9:11 a.m. “In the whole zone of totality there could not have been a better observing point, not a point where one could realize better the grandeur of this overwhelmingly impressive phenomenon,” Luyten wrote.
By then Los Angeles was abuzz with activity as well. The airship was about 19 miles off Montauk Point, at the eastern tip of Long Island. Scientists and crew had begun their final preparations not long after dawn, as the moon began inching across the sun’s face. There was no heat in the airship, so expedition members wore fur-lined coats, and everyone who could spent time in the galley, noshing on “ice-cold bananas, sandwiches, and hot coffee,” the USNO reported.
Astronomers originally considered conducting all their observations from atop the airship, but quickly dropped the idea. Instead, they set up most of their gear on the starboard side of the spacious passenger cabin, with some in the galley or in a doorway at the cabin’s rear. Some of the windows had been removed to provide a clearer view.
The photographic equipment included two pairs of telescopic cameras, one to view the inner portion of the corona, the sun’s hot but faint outer atmosphere, which was the primary target of most of the eclipse-watching scientists. A second pair of cameras would capture the corona’s dimmer outer portion.
A scientist from the Bureau of Standards operated a spectrograph, which split the corona’s light into its individual wavelengths in an effort to measure its temperature and composition. Chief photographer Alvin K. Peterson operated from an open cockpit, taking both still and motion pictures. “His position was a very exposed one and his fingers and cheeks were partially frozen,” the USNO report noted, “yet he declined all suggestions that he leave his designated post before the completion of his task.”
Members of the airship’s crew were recruited to assist the astronomers. They kept time, logged positions and looked for any comets that might be visible near the eclipsed sun. One crewman was tasked with turning a crank on a camera mount once per second to compensate for the airship’s forward motion.
As totality approached, Los Angeles was cruising at an altitude of 4,500 feet, with three of its engines switched off to minimize vibrations. Clouds partially covered the sun as little as five minutes before totality, but vanished shortly before the sun did.
The moon’s shadow swept over the airborne giant in an instant. “Picture, if you can, a summer thunderstorm which blackens a distant area of the sky and as it approaches appears very threatening,” Lieutenant Herbert V. Wiley later wrote. “The whole sky grows darker as the storm develops. The firmament takes on an ominous aspect. Suppose that instead of the usual hour for the storm to develop and approach, all this happened in three seconds. Then you have an idea how this shadow appeared over the great relief map of southern Connecticut and Long Island Sound and swept down on the airship.”
When the sun vanished, the astronomers furiously clicked pictures, changed film and logged their observations—totality lasted just 2 minutes, 4 seconds. Then the first rays of sunshine emerged from behind the moon and the brief night ended.
After the partial phase of the eclipse ended an hour or so later, Los Angeles headed for home, skipping a planned flyover of New York. It arrived at Lakehurst at 2:30 p.m. The wind was still blowing at 16-22 mph, so “considerable trouble was experienced in landing,” the USNO reported. “It took an hour to bring the ship to the ground.” During the process, Los Angeles vented an estimated 300,000 cubic feet of precious helium, worth $20,000, the AP noted.
During the cruise back to base, Watson Davis, an editor for Science Service, transmitted a report describing the airship’s work. There was too much interference for a voice broadcast, so he used Morse code. “Perhaps when the plates of today’s expedition are developed, a new element, or a new secret, will be revealed to science, just as years ago helium was discovered in the sun during a total solar eclipse, long before it was known to earth,” he reported.
Alas, the optimism was all hype. The big airship wasn’t as stable as astronomers had hoped. It pitched and rolled throughout their observations, blurring the pictures (a problem shared with photos snapped from the higher-flying airplanes). “This angular movement combined with the vibratory movements, due to the engines, made the resulting photographs a series of overlapping images….As it is, their principal usefulness is to indicate the difficulties that airship observers of eclipses must surmount if they are to expect satisfactory results from such expeditions,” the USNO noted.
While it was a disappointment for astronomers, the flight yielded some positive results for the Navy. Airship crews gained precious flight and ground experience and the service garnered positive publicity for its airship program.
Another government agency profited as well. The day of the eclipse, the Post Office reported that one shipment of movie film to points west was the most expensive package yet for its fledgling airmail service: $536.14—a record haul from the quest to catch a shadow.
Damond Benningfield is a freelance writer and audio producer in Austin, Texas. Additional reading: In the Shadow of the Moon: The Science, Magic, and Mystery of Solar Eclipses, by Anthony Aveni; and USS Los Angeles: The Navy’s Venerable Airship and Aviation Technology, by William F. Althoff.
This feature originally appeared in the January 2022 issue of Aviation History. Don’t miss an issue, subscribe today!