July
Evening Skies
By: Rod
Kennedy
For many who grew up in Natrona County, the Casper Planetarium brings up fond memories of school field trips to the big room where the lights go down and the stars come out. Yet the small community planetarium is somewhat rare. In fact, the Casper Planetarium is one of only three in the state of Wyoming; the other two are at the University of Wyoming and in Gillette. For those not fortunate enough to have experienced one of these wonders of technology, the question arises: “What is a planetarium anyway?”
Regardless of the technology involved, all planetariums are essentially the same. All planetariums are a room, usually circular, with a dome shaped ceiling and a machine that simulates the night sky. This remarkable theater began in 1913 when astronomer Max Wolf had the dream of a device that would accurately produce the stars an planetary motions in an indoor setting. The project was given to the Carl Zeiss optics company in Germany. Hundreds of trials and calculations later the Zeiss Mark I was unveiled in 1923 under a 16 meter dome. By 1936 planetariums had cropped up in several major cities, including the Adler Planetarium in Chicago.
However, the Zeiss machines were extremely expensive. That same year, Armand Spitz set out to build a projector that would be small enough and cheap enough for small museums and schools to have. The first SPITZ star machine was a small dodecahedron. By the 1960’s this odd looking machine had been replaced by the SPITZ A3 and A3P, the most abundant and widely produced planetarium system ever. Both A3 systems had replaced the dodecahedron with the more familiar spherical star ball.
The 1960’s were heady times for newly opened planetariums, thanks in large part to the growing space race between the United States and former Soviet Union. Never before or since has there been such emphasis on mathematics, science and engineering; and the nation’s planetariums reaped the benefits. Under their domes the average citizen had access to the stars. In addition, the success of the Apollo program provided real images of another world. All a planetarium presenter needed was a slide projector and a set of slides from NASA. Some presenters even added music, albeit played on reel-to-reel tape. Suddenly planetariums were no longer merely theaters that simulated the night sky; they were now home to multimedia presentations.
When the Apollo program came to an end, interest in planetariums did not end but it diminished significantly. At least until a daring project called Viking landed two landers on the surface of Mars. The Viking landers not only provided never before seen images of one of the solar systems most fascinating planets. During this time technology advanced and planetarium programs evolved to present audiences with more sophisticated multi-media programs. In addition, systems evolved to present programmed or “canned” programs. These programs did not require the planetarian to do any more than start the sound track and monitor the slide projectors. Some innovative planetarians even took to writing and producing their own planetarium programs. However production of these programs could take as long as 8 months to 1 year. Planetarium production was generally out of the question for small planetariums with small staffs.
The 1980’s gave planetariums an even greater treasure of images for use in programs. These came from the Voyager I and II space craft which send back stunning images of Jupiter, Saturn, Uranus and Neptune. Reel-to-reel tape decks gave way to ADAT tape systems that used VHS sized audio tapes and control systems continued to improve.
Today analog sound systems are being replaced with digital systems and slide projectors are being replaced by digital video projectors. The SPITZ A3 star machines are all but gone and the A3P’s are the planetarium equivalent of World War II vintage aircraft. The planetarium systems designed by SPITS now include greater star resolution, more accurate planetary motions and far greater control capabilities. While there are still many A3P’s out there most are slowly being replaces with more modern machines, some from SPITZ some by Zeiss and some by the newcomer to the planetarium scene, the Japanese Chronos. Some planetariums are even replacing their optical machines with fully digital computer controlled systems.
Some have resisted the transition to digital planetarium technology, citing the superiority of 35mm slide film over any digital image. Opponents of digital star fields complain that the star quality is only a fraction of that from a good optical-mechanical machine. Yet the slow replacement of older systems has been like any technological advance. As new technologies emerge, old ones fade away. Knowledge of how they work is lost, companies stop producing parts or they become too difficult to maintain. Planetariums have a choice of upgrading or shutting down.
Thanks to many of these technological advances now even small planetariums can produce their own programs. Computers are smaller and faster and image production has reached the point where one person can produce images as quickly and easily as a professional. Sound tracks can now be produced at a desk instead of a sound studio and with the aid of open source software anyone can produce 3D animated images of the quality seen only in Hollywood productions. Digital technology is not only transforming planetariums, but planetarium staffs as well.
