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The Zeiss II Planetarium Projector was the one and only planetarium projection system in service at The Buhl Planetarium and Institute of Popular Science in Pittsburgh, Pennsylvania U.S.A.
It was the last Zeiss Mark II to be constructed. The Carl Zeiss Company did not produce Zeiss Mark III (all are upgraded Mark II projectors) or Mark IV projectors until well into the 1950s.
Buhl Planetarium's Zeiss II was the fifth major planetarium projector in the Americas. Earlier Zeiss II projectors were installed at the Adler Planetarium and Astronomy Museum in Chicago in 1930, Fels Planetarium of Franklin Institute in Philadelphia in 1933, Griffith Observatory and Planetarium in Los Angeles in 1935, and the original Hayden Planetarium of the American Museum of Natural History in New York City in 1935