Planetarium
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Your Cosmic Virtual Reality Machine

+ Von Del Chamberlain +

Virtual Reality! A buzz-word of our age. Most people think of it as new, but one of the grandest virtual experiences has been with us for a long time. It is the planetarium, and it began more than 2,200 years ago.

It is said that Archimedes made the first planetarium in the 3rd century B.C. It was described as a rotating globe that could illustrate the movements of the "seven wanderers" (Sun, Moon, Mercury, Venus, Mars, Jupiter and Saturn). When we consider these early devices, we must remember that the word planetarium refers to planets. Originally they were inventions that modeled the movement of the planets. We have no drawings of the one made by Archimedes, but it probably consisted of a skeletal set of metal rings, representing the apparent sphere of the sky, with some sort of gear mechanism to give motion to the planets. This device was an outgrowth of visualizing the starry sky as an immense sphere surrounding us, an idea that goes way back. One familiar version of this is the famous Roman marble sculpture of the kneeling Atlas holding the sphere of the heavens upon his shoulders, the Atlante Farnesiano, located in the National Museum of Naples. The sphere he holds has constellations carved upon its surface.

About 1650 A.D. Andreas Bush of Limberg, Germany made an 11 foot diameter globe that about ten people could enter to watch stars and constellations, painted on the inner surface, rise and set as the globe was rotated about them. In 1758 Roger Long at Cambridge, England, erected a hollow star globe at Pembroke College. Thirty people could go inside this 18 foot diameter celestial sphere to study the apparent movements of the heavens. Along side these spheres of the sky European inventors were making orreries, gear-wheel devices that illustrated the relativemotions of the planets, and some of these were imbedded in ceilings so that people could sit under them to watch how the planets moved. One such was built in the early 1920's by an engineer of Carl Zeiss for the Deutsches Museum in Munich, Germany. It was 37 feet in diameter, with a 9-inch lighted glass globe representing the Sun, and it had a platform beneath the model of the Earth that carried an observer who could look through a periscope to watch how the other planets appeared to move, as seen from Earth, against a wall of lights representing the brightest stars of the zodiac.

The modern planetarium was born when Walter Bauersfeld of the Carl Zeiss company in Jena conceived of putting a projector under a large dome to simulate the motions of the planets and stars. In August 1923 the first stars and planets were projected onto a 52.5 foot diameter dome located on the roof of the Zeiss works, where thousands of people enjoyed this "wonder of Jena." The following year the projector was moved to the Deutsches Museum in Munich where large crowds went to see the "optical-mechanical marvel of our age." With this facility, the concept of a planetarium changed in the public mind, for most people came out of this cosmic theater with stars on their minds more than planets.

Zeiss planetarium projectors were improved and here in America one opened in Chicago in 1930, then in Philadelphia, Los Angeles, New York and elsewhere. In 1945 an American, Armand Spitz, began the development of a less expensive projector within the means of small museums and even schools, and in the 1950's Japanese manufacturers started producing planetarium instruments. The technology of all of these improved constantly, amid rumors of the possibility of such things as laser planetariums. An important part of the planetarium technological story took place in Salt Lake City. Lets see how this happened.

In 1964 the first city library, which had opened in 1905, was scheduled to shut its doors as a new, larger and more modern, library would open. Gail Plummer, professor of speech and drama at the University of Utah and chairman of the Salt Lake City Library board, had been interested in planetariums for many years, and his personal vision had become that of seeing the old building become the home of a theater of the sky. As he contemplated this, Mrs. George T.Hansen called him to inquire about what was going to happen to the grand old building. Mr. Plummer replied that he was concerned about this, but that he knew what he would like to see done with it. He told Mrs. Hansen about his dream for a planetarium in Salt Lake, and she indicated that she wanted to think about it. It took her only a few minutes to consider the matter. She called Mr. Plummer again to tell him that she would give the city funds for a planetarium in memory of her deceased husband.

The Hansen gift made possible remodeling of the building and installation of a new type of Spitz instrument that was engineered to illustrate space craft maneuvers and show motions in the sky that one might experience from places in the solar system other than on Earth. The planetarium opened on November 26, 1965. With the death of Mrs. Hansen, the name was changed to the Mr. and Mrs. George T. Hansen Planetarium, Space Science Library and Museum to honor the woman who made it all possible as well as her beloved husband.

In the late 1970's, Brent Watson and Stephen McAllister were working at Evans and Sutherland Computer Corporation, the world leader in computer graphic image simulations. Since both of these individuals were interested in astronomy, they began work on a digital planetarium instrument. In 1983 the first Digistar was installed in Virginia, then in 1985, an improved unit replaced the Spitz projector at Hansen Planetarium for its 20th birthday.

Digistar opened a whole new universe of possibilities in the planetarium field. Where once instruments could simulate the appearance of stars and planets as seen from within the solar system, now audiences could be virtually transported to anywhere within the field of stars contained in Digistar's data bank. Thus, audiences could get a good idea of what the sky would look like from hundreds of light years out into the galaxy, watching the view change in a 3-D presentation along the way, or they could see how star patterns change over millions of years of time. In addition, using this computer graphic capability, it was possible to model all sorts of additional things from the DNA that makes people what they are to the lattice of clusters of galaxiesthat defines the structure of the universe. As scientists get more detailed information it can be programmed into Digistar memory and revealed visually in the planetarium "sky."

The contemporary planetarium is a virtual simulation theater of the cosmos with powerful capability for the purpose of elevating knowledge and thinking of people. At the center of a planetarium lies a high technology projector that casts images of the sky onto the dome to transport human minds into the heart of an atom or out into the Galaxy. All this has emerged from a long history of interest in simulating the wonders of the starry sky, an interest that must have began when the first human eyes looked upward.

Visit your local planetarium. This is your cosmic virtual reality place, where you can embark upon journeys of exploration into realms you can not visit in any other way.

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