Planetarium history: Nazis persecuted inventor Rudolf Straubel of Zeiss.

The Tragic, Untold Story of the World’s First Planetarium

The Tragic, Untold Story of the World’s First Planetarium

The state of the universe.
Feb. 23 2014 11:54 PM

Under the Dome

The tragic, untold story of the world’s first planetarium.

Drawing of the projection planetarium in Munich, ca. 1923.
Drawing of the projection planetarium in Munich, ca. 1923.

Courtesy of the Deutsches Museum.

It is “unusual, even weird and startling,” wrote a journalist in 1924, upon seeing the world’s first projection planetarium. “It is the best ‘movie’ I have ever seen,” said another, and according to a third, the star-dome was “nothing more nor less than a playhouse in which the majestic drama of the firmament is unfolded.”

Daniel Engber Daniel Engber

Daniel Engber is a columnist for Slate

The new machine that had been erected on a rooftop in Jena, Germany, dazzled with a Jazz Age marriage of science and style: Optical projectors cast dots of light against the curved ceiling of a darkened theater, making stars that twinkled like the sequins on a flapper’s dress. “It became a phenomenon in a way that nobody envisioned,” says Jordan D. Marche, author of the definitive history of American planetariums, Theaters of Time and Space. By 1935, domes had been installed in Chicago, Philadelphia, Los Angeles, and New York City, and interest in astronomy was flourishing. Contemporary reports described crowds falling silent as the lights went down and then gasping in astonishment as the concrete vanished into constellations.

That glitz and awe, still potent after all this time, has its origins 100 years ago today. At a meeting held in Munich on Feb. 24, 1914, an engineer at the Zeiss optics firm named Walther Bauersfeld had the idea to project the sun and moon and planets on the inside of a dome. Rather than rely on moving arms and metal discs, Bauersfeld proposed to shine the shapes onto the ceiling from a central source of light. Museums around the world would celebrate this achievement: When the Philadelphia planetarium opened up in 1933, at an invitation-only shindig with a string quartet, Bauersfeld got a medal in absentia.

Rudolf Straubel.
Rudolf Straubel.

Courtesy of Linda Langer Snook


A month before that party, though, another scientist at Zeiss—who was just as important to its history—had been booted from his job. Rudolf Straubel, the firm’s long-serving scientific director, chose to resign his post rather than divorce his Jewish wife. Straubel had been at that 1914 meeting, too; indeed, he’s said to be the one who expanded Bauersfeld’s idea to project not just the planets but the stars. In the years that followed Straubel’s resignation, the Zeiss planetarium mesmerized crowds with visions of the heavens. But as the invention grew in fame, a tragedy took bloody shape on the ground in Jena. Bauersfeld won a medal. Straubel sank into a private hell of Nazi persecution.

The details of this story were uncovered only several years ago, by a computer programmer in California named Peter Volz, whose grandfather worked at Zeiss during this period. With the help of Straubel’s extended family, Volz has put together a two-part article for Planetarian, the journal of the International Planetarium Society. There he argues that Straubel’s contributions to the planetarium were covered up by Nazi propaganda and that the fact of this cover-up was itself erased during the postwar years.

As Volz makes clear, Straubel had been involved in the planetarium project from the very start. In the early 1910s, the director of a new industrial museum in Munich asked the Zeiss firm to build a pair of astronomical exhibits. The first would be an orrery—a working model of the planets as they swing around the sun. These globe-and-stick devices had been common since the early 18th century, powered first by gears and pendulums, and later by electric motors. The second exhibit, a celestial globe, would show the heavens as they looked from the surface of the Earth. Traditionally this took the form of a giant sphere with constellations painted on its inner surface or holes poked through its walls for stars. A visitor would sit on a stable platform as the celestial globe spun around him—by means of water power, in its early incarnations—to show how stars appear to move with the changing of the seasons.

Straubel would help with both requests. As scientific director and member of the Zeiss management team, he had an entrepreneurial role, farming out ideas to junior engineers and helping them negotiate whatever problems they encountered. Though he often constructed things himself—including a large mirror in the front yard of his home, for an experiment in solar energy—Straubel rarely took credit for the company’s achievements. When signing business correspondence, he often used the founder’s name, “Carl Zeiss.”

That may be one reason why Straubel never got much recognition for his work in Munich. According to Volz’s research, Straubel had met with the director of the museum to discuss the planetariums at length in 1913, at a time when the idea of using light projection was already on the table. And Straubel was certainly present at the planning session the following February, at which he and Bauersfeld concluded that the globe should be refigured as a stationary dome, with a rotating projector at its center. This idea, whoever came up with it, made the modern planetarium possible.

Straubel’s legacy, or lack thereof, would be fixed in 1933. The local Nazi minister of the interior, a brutal ideologue and drunk named Fritz Wächtler, sought to overhaul the management at Zeiss, which he described as being “infested with Marxists and Liberals.” (Wächtler would later be executed by the S.S. for cowardice.) Straubel was given an ultimatum by his fellow directors at Zeiss, who now included Walther Bauersfeld: Either divorce his wife or quit his job. He chose the latter.

By 1937, 4 million people had visited planetariums in the United States. It was “truly an awesome moment,” said one visitor to the dome in Philadelphia. “I had the feeling of being completely detached from people and things.” By 1938, Straubel had been removed from lecturing at the University of Jena on account of his “45 years of Jewish relations;” his wife, Marie, had been arrested and then released on Kristallnacht, and their son Harald—until then a Zeiss crystallographer—had been fired.