For the 2001 November issue of The Guide Star --

For the 2001 November issue of The Guide Star --

60th Anniversary of Buhl's Observatory

By Glenn A. Walsh < >

November 19 marks the 60th anniversary of the dedication of "The People's Observatory" at Pittsburgh's Buhl Planetarium and Institute of Popular Science. Although dedicated to public use, The People's Observatory was constructed to research observatory specifications, at a cost of $30,000(1941 dollars).

This included the erection of the Observatory's new and fairly unique telescope, the 10-inch Siderostat-type Refractor Telescope(what Leo Scanlon called the "horizontal refractor") produced by Chicago's Gaertner Scientific Company. This telescope continues to be the second largest operable, Siderostat-type telescope in the world !

Well-known Astronomer Harlow Shapley, who was then Director of the Harvard College Observatory, presented the keynote address at the dedication ceremony. First Light, through the Siderostat-type telescope, came from the ringed planet Saturn. Of course in 1941, Saturn was the only planet known to have rings.

The Buhl Planetarium and Institute of Popular Science had actually been dedicated and conveyed to the City of Pittsburgh, by the Buhl Foundation, on 1939 October 24. Prior to the Observatory dedication ceremony, Buhl's Third Floor Observatory had been used by Leo Scanlon and the Amateur Astronomers' Association of Pittsburgh(AAAP) for public observing with portable telescopes, as is done today at the annual open house of the Allegheny Observatory. Once the Siderostat was in use, Leo scheduled AAAP members to supervise public observing sessions on clear evenings--at that time, Buhl was open the public every evening(except New Year's Day) until 10:30 p.m.!

Along with the Zeiss II Planetarium Projector(now the oldest operable, major planetarium projector in the world !), the Buhl Planetarium also ordered a portable telescope from the Carl Zeiss Company in Jena, Germany in 1939, for use in the Observatory. To the dismay of Buhl officials when opening the package from Germany, they received a 4-inch terrestrial refractor telescope; of course, they had ordered an astronomical refractor. However, with the commencement of World War II on 1939 September 1, they could not return the telescope and have an astronomical refractor sent in its place. Hence, they had to

make-do with a terrestrial refractor, and so today the City of Pittsburgh owns a good Zeiss telescope(now used at the Henry Buhl, Jr. Planetarium and Observatory of The Carnegie Science Center) with a very interesting history!

In addition to evening use, the Siderostat projects a superb display of the Sun onto a large projection screen, showing both sunspots and solar granulation. Also, during daytime hours, the public has been able to view the planets Mercury, Venus(showing phase), Mars, and Jupiter(including cloud belts), as well as the Moon and stars down to third magnitude, with the Siderostat.

Although primarily used for public observing, the Siderostat has been used for some research, from time-to-time. During the 1980s, Buhl Planetarium Lecturer Francis G. Graham(Founder of the American Lunar Society, who spoke at a recent Laurel Highlands Star Cruise) took photographs of the South Pole area of the Moon, as part of a cooperative research project with other American astronomers. These photographs aided the production of a better map of the South Pole area of the Moon, than existed at that time.

Another interesting historic anecdote: On the same evening of the Observatory dedication, Buhl started a new Planetarium Sky Show and opened a new gallery exhibit. The Sky Show, regarding Celestial Navigation, was titled "Bombers by Starlight"(Buhl provided Celestial Navigation classes to many military servicemen, during World War II). The new exhibit, in Buhl's lower-level Octagon Gallery(which encircles the planetarium projector pit, below the planetarium theater) was titled "Can America Be Bombed?" This exhibit opened two and one-half weeks before the Japanese bombed Pearl Harbor, Hawaii !

More information on the history of The People's Observatory at Buhl Planetarium can be learned at URL:

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