September, 2000



Zeiss II Planetarium Projector

The most historic piece of functioning equipment is the Zeiss II Planetarium Projector, in Buhl Planetarium's "Theater of the Stars," which is now the oldest operating, major planetarium projector in the world !!! This projector, purchased in 1938, was specifically designed to operate in a planetarium theater with a 65-foot diameter dome. If the Zeiss II Projector were ever removed from the Buhl Planetarium building, this projector would be rendered completely useless ! Then, Pittsburgh would no longer have the oldest operating, major planetarium projector in the world.

Buhl Planetarium's Zeiss II Projector was the first planetarium projector in the world to be placed on an elevator, a fairly unique, "worm-gear" elevator built by the Westinghouse Electric Corporation. As such, there is no need for the Zeiss II Projector to be removed from the building. When not in use, the projector can simply be lowered below the floor level. Then, the Theater's movable stage[Buhl Planetarium was the first planetarium theater to include a stage for theatrical performances] can be brought out for other presentations.

10-inch, Siderostat-type, Refractor Telescope

A second, fairly unique, piece of equipment, on the Buhl Planetarium building's third floor, is the 10-inch, Siderostat-type, Refractor Telescope. Dedicated in 1941 by well-known, Harvard University Astronomer Harlow Shapley, this telescope is the second largest Siderostat-type Telescope in the world!

Buhl Planetarium's small third floor was specifically designed to be an Astronomical Observatory, and the Siderostat-type Telescope was specifically designed for this Observatory. As with the Zeiss II Projector, if the Siderostat-type Telescope were ever removed from the Buhl Planetarium building, the telescope would be rendered completely useless !

Actually, considering the size and configuration of the third floor, it would not be easy to use this space for any other purpose. While the rest of the Buhl Planetarium building is both heated and air-conditioned[the Buhl Planetarium building was the first public building in the City(and, possibly the State) to be air-conditioned, when it opened in 1939], this is not the case for the third floor. One-third of the third floor[the public observing area] is heated but not air-conditioned. Due to the need for stable air currents for the telescope, the other two-thirds of the third floor[where the telescope is actually located] is neither heated nor air-conditioned!

Four Artifacts on the Buhl Planetarium building's First Floor

  1. Large World Map - Along the western wall of the Great Hall is a large map of the world, which was originally produced by the United States Maritime Commission for the 1939 World's Fair[which highlighted the future of technology] in New York City. During the 1939 World's Fair, this World Map was considered the largest Mercator's Projection Map in the world !!! It would be difficult to find a new home for this historic artifact.
  2. Compass/Pendulum Pit - Just east of Buhl Planetarium's front doors is a beautiful brass and marble[Florentine marble] pit that displays the true cardinal points of the compass. Originally, this was the home of Buhl Planetarium's Foucault Pendulum[which provides a classic demonstration that the Earth rotates on its axis], which is currently displayed at The Carnegie Science Center. Completely built into the building's floor, I cannot think of any way this could be moved elsewhere. It would be a shame to lose such a beautiful and historic artifact, which still does function to show the true compass directions. This pit could be used for other types of displays. And, considering that a pendulum is not that expensive, a new pendulum could some day swing, once again, in this pit.

  3. History of Technology Mural - High along the southern wall of the Great Hall is a large mural depicting the rise of technology from pre-historic times to the present. Commissioned by the U.S. Steel Corporation, the mural includes a special lighting system with a control unit that changes the lighting. With the control unit, a tour guide can control the lighting during an educational talk on the mural. Particularly considering the size of the mural, it would not be easily moved elsewhere.

4] Original Lecture Hall Seating - Although the current seating in the Planetarium Theater[a.k.a. Theater of the Stars] is not original, the seating in the Lecture Hall[a.k.a. Little Science Theater] is original 1939 seating. Assuming that the Lecture Hall would continue to be used as some type of theater/auditorium, this original seating should be restored, not replaced. One company which specializes in seat restoration is Country Roads, Inc. of Greenville, Michigan; this company restored the seats in the 97-year-old concert hall of Boston's New England Conservatory of Music: Jordan Hall, in 1995. To meet present-day fire codes, the Lecture Hall's current seating capacity of 250 would have to be reduced to around 175-200, to allow the addition of two new aisles along both Lecture Hall walls[currently, the Lecture Hall has only one central aisle].



  1. Painting of Halley's Comet - Donated by the late Willard F. Rockwell, Jr., [former Chairman of Rockwell International Corporation and Founder of Astrotech International Corporation], in 1986.
  2. Epideoscope - Antique, overhead-type projector used for Buhl Planetarium's first Life Sciences presentation, "The Micro Zoo."
  3. Oscilloscope - Large older model, used for presentations in the Lecture Hall.
  4. Lecture Hall Science Table - Used for Science presentations and lectures.

These four artifacts could be moved elsewhere in the building or placed in storage, if necessary. Considering that there are large picture windows between the Observatory's Telescope Room and Public Observing Room, the Epideoscope and Oscilloscope could be displayed in the Telescope Room.

Internet Web Site - History of

The Buhl Planetarium and Institute of Popular Science, Pittsburgh:

< http://www.planetarium.cc >



September 18, 2000

Glenn A. Walsh

633 Royce Avenue

Pittsburgh, Pennsylvania 15243-1149

Telephone: 412-561-7876

Electronic Mail: < gawalsh@planetarium.cc >

Internet Web Site: < http://www.planetarium.cc >