Historic Artifacts and Equipment Which Remain in
The Buhl Planetarium and Institute of Popular Science

Assets Worth Preserving

July, 1998

Cub Scouts viewing the Foucault Pendulum at The Buhl Planetarium 
and Institute of Popular Science

The Foucault Pendulum provides a classic demonstration that the Earth rotates on its axis, at The Buhl Planetarium and Institute of Popular Science which, beginning on 2003 February 15, is being utilized by the Children's Museum of Pittsburgh. Under the swing of the Pendulum, the beautiful brass and marble Pendulum Pit also shows the true cardinal points of the compass.

The Foucault Pendulum was unveiled, with the dedication of the Buhl Planetarium building, on 1939 October 24. The Foucault Pendulum was one of Buhl Planetarium's original " talking exhibits," state-of-the-art in 1939. A special audio room [across the hallway from the Planetarium audio room] included turntables which would play a special record, which would explain the exhibit, at the press of a button by the visitor. The sound came from a speaker in the Pendulum Pit. This speaker, no longer in use, can still be seen in the Pendulum Pit--the last vestige of the Buhl Planetarium "talking exhibits."

In the photograph, Buhl Planetarium Floor Staff member Dewitt Peart explains the Science of the Foucault Pendulum to a group of Cub Scouts. This photograph was published in February of 1956.

Internet Web Site Master Index for the History of
The Buhl Planetarium and Institute of Popular Science, Pittsburgh

Building and Science Museum

The Buhl Planetarium and Institute of Popular Science building is a structure constructed of Indiana Limestone, with much of the interior walls composed of Florentine Marble. It opened to the public on Tuesday, October 24, 1939. Beautiful statuary, by well-known sculptor Sidney Waugh, and inscriptions relating to Astronomy and other Sciences adorn the building's exterior. This building was the first public building in the city(and, possibly, the state) to be built with air conditioning.

While several major cities, including Pittsburgh, had museums of natural history, The Buhl Planetarium and Institute of Popular Science was one of only a hand-full of institutions which had an emphasis in the physical sciences. Chicago and Philadelphia were the only major cities, at the time Buhl opened to the public, which had large museums specializing in the physical sciences; a small science museum, adjacent to the Griffith Observatory and Planetarium in Los Angeles, also existed. Although most people thought of Buhl as primarily an astronomy museum, from the time it opened Buhl's galleries presented exhibits and demonstrations in many different physical sciences, and some life sciences. The Buhl Planetarium and Institute of Popular Science was one of the early pioneers in developing the concept which would later come to be known as the "Science Museum" or "Science Center."

Planetarium Projector and Theater

The Buhl Planetarium was the fifth major(i.e. projector capable of displaying the stars seen in both the northern and southern hemispheres) planetarium to open in the United States. It was the first planetarium projector in the world to be placed on an elevator(a rather unique, worm-gear elevator produced by the Westinghouse Corporation--visiting engineers would be taken down to the Zeiss pit, and they would marvel at the four huge worm-gears which raise and lower the projector). After the projector is lowered below floor level, a stage(one of two stages in the Planetarium Theater) is created above the projector; it was the first planetarium theater to include a stage for theatrical performances.

The Planetarium projector is a Zeiss Model II, produced in 1938 at the Zeiss Optical Works in Jena, Germany. It was the last planetarium projector built before World War II, when the factory began manufacturing bomb-sights for German aircraft(eventually, the factory was bombed by the Allies). The Zeiss II Planetarium projector is now the oldest operating, major planetarium projector in the world!!! It is unclear whether any other Zeiss II projectors still exist; however, the couple which did exist a few years ago had been extensively modified from their original manufacture.

The Planetarium Theater, originally known as the "Theater of the Stars," is one of the largest such theaters in the world. It includes a 65-foot diameter planetarium dome. Prior to the building's closing, the theater had seating to accomodate 425 people(this includes 381 permanent seats). In 1939, it was the first planetarium theater(and, perhaps, the first theater) to install a special sound system for the hearing-impaired(both air-conduction and bone-conduction headsets were available).

Astronomical Observatory

Originally known as "The People's Observatory"(a name which lost favor with the rise of several Communist "People's Republics" after World War II), this Astronomical Observatory was specifically designed for observational use by the general public, but constructed to professional observatory specifications, at a cost of $30,000(1941 dollars). It was dedicated on Wednesday Evening, November 19, 1941, with the keynote address given by Harlow Shapley, one of the most renowned astronomers of the twentieth century(at the time, he was Director of the Harvard College Observatory). "First light," through the Siderostat-type telescope, that evening, was a view of the ringed-planet Saturn.

The chief instrument of the Observatory is a ten-inch, "Siderostat-type" refractor telescope. This telescope is the second largest(primary lens aperture) Siderostat-type telescope in existence(third largest that ever existed); it is the largest one used, primarily, for public observing.

The Siderostat, or "Sidereal Coelostat" arrangement, was designed in the mid-nineteenth century by the famous French Scientist, Jean Leon Foucault(who also invented the Foucault Pendulum, which presents the classic demonstration of the Earth's rotation on its axis); Foucault was a sickly man and died before he had the chance to constuct a Siderostat-type telescope.

A Siderostat-type telescope is permanently and horizontally mounted on a concrete pier; the telescope does not move. A flat, first-surface mirror reflects celestial objects into the telescope. In cold weather, this allows the public to remain in a warm observing room while the telescope is in the cold air. This arrangement relieves neck strain from looking through the telescope and prevents the public from inadvertantly misaligning the telescope. The Observing Room, at Buhl's Observatory, was specifically designed to allow use of the Siderostat-type telescope, during evening observing sessions only, without an attendant; this capability was updated by The Carnegie Institute maintenance staff. Buhl's telescope also presents, to the public, an excellent image of sunspots and other phenomena on the surface of the Sun, utilizing the safe projection method of observation.

Other Historic Equipment and Artifacts

Large World Map - Originally created by the U.S. Maritime Commission for the 1939 World's Fair in New York City, at the time of creation it was considered the largest Mercator's Projection Map in the world! This map is currently displayed along the western wall of the first floor's Great Hall.

U.S. Steel Mural - This large mural, attached to the southern wall of the first floor's Great Hall, depicts the rise of technology. A special lighting system for this mural exists, with the control unit located in the former office of Buhl's Discovery gift shop.

Painting of Halley's Comet - This painting, from Great Britain, was donated to Buhl in 1986 by the late Willard F. Rockwell, Jr., former Chairman of Rockwell International Corporation and Founder of Astrotech International Corporation. This painting is currently located on the eastern wall of the Lecture Hall(a.k.a. Little Science Theater); it could be moved elsewhere.

Epideoscope - Antique, overhead-type projector used for Buhl's first Life Sciences public presentation, "The Micro Zoo." It is unknown whether this projector still operates. It is currently located in the Lecture Hall, but it could be displayed elsewhere.

Oscilloscope - Large older model, used for presentations in the Lecture Hall; it could be used and displayed elsewhere.

Foucault Pendulum in beautiful brass and marble Pendulum Pit - The Foucault Pendulum provides the classic demonstration that the Earth rotates on its axis. Under the swing of the Pendulum is displayed the true cardinal points of the compass.

Grand Clock - This clock, which still operates, greets the public as they enter the building's front doors; its control unit is located on the second floor.

Beautiful Wood-Paneled Library - This is located on the building's second floor.

Lecture Hall Science Table - This is located in the front of the Lecture Hall and is still usable for any type of science presentation.

Lighted Picture Displays - Several lighted picture display cases exist, either imbedded into the wall(Planetarium hallway) or mounted on the wall(Observatory); any type of picture can be displayed.

Rainbow Wallpaper - Wallpaper which refracts light, at the entrance to the East Gallery.

Glenn A. Walsh
633 Royce Avenue
Pittsburgh, Pennsylvania 15243-1149 U.S.A.
Telephone: (412) 561-7876
Electronic Mail: < Buhlassets@planetarium.cc >

Internet Web Site Master Index for the History of
The Buhl Planetarium and Institute of Popular Science, Pittsburgh

Disclaimer Statement: This Internet Web page is not affiliated with the Henry Buhl, Jr. Planetarium and Observatory,
The Carnegie Science Center, or The Carnegie Museums of Pittsburgh/Carnegie Institute.

This Internet, World Wide Web Site administered by Glenn A. Walsh.
Unless otherwise indicated, all web pages in this account are Copyright 1999-2001, Glenn A. Walsh, All Rights Reserved.
Additions and corrections to: Buhlassets@planetarium.cc

Last modified : Monday, 09-Aug-2010 21:49:34 EDT.