Simulated Space Travel

Simulated Space Travel

The man-made planetarium sky provides an excellent setting for presenting achievements in the greatest adventure of all time – the physical conquest of space. A variety of planetarium shows con be devised to stimulate space travel and, in the light of present knowledge, give a preview of conditions on the moon and other worlds. The younger generation, for whom space ships and interplanetary expeditions have become fairly common topics of conversation, take to these shows like ducks to water. But once again eager curiosity and enthusiasm have to be directed toward the goal of understanding and critical evaluation.

The growing general interest in space travel and space studies led Carl Zeiss Jena to introduce a planetarium instrument that was more versatile and sophisticated than earlier models. It can be used to stimulate orbital flight around the earth and also to portray the sky and the movements of the sun and planets as seen from the moon. When spectators see these effects they can also be persuaded into thinking that they are astronauts on their way to a successful lunar landing.

At the Morehead Planetarium, University of North Carolina, Chapel Hill, the Zeiss instrument was specially adapted to brief astronauts training for Project Mercury. In the first stages of the instruction the astronauts learned to identify stars and constellations, particularly those adjacent to the proposed orbital space path. A similar although greatly simplified training was available to space-minded youngsters at the McLaughlin Planetarium in Toronto, Ontario, Canada. They may never become astronauts but they should at any time and place be able to orientate themselves by the stars.

Deep Space. Illustration by Elena

Star Navigation

Long ago sailors learnt to steer by the stars. Later, they tried to fix their position in uncharted waters by using the stars, but progress in this field was slow and difficult. In the 18th century two great inventions, the sextant and the chronometer, together with the introduction of more accurate astronomical tables, heralded big advances. Among the latter were some of the modern methods in star- or astronavigation which made possible the determination of both latitude and longitude. These quantities can now be obtained from aboard ship by making simultaneous observations of the altitudes of two stars, or from two altitudes of the same star taken at different times.

Lectures in astronavigation can play an important part in the life and work of a planetarium. The planetarium sky represents part of a celestial sphere and can therefore be used as a background for showing the celestial meridian, celestial equator, part of the right ascension-declination framework, and the nautical of PZS triangle. Consequently, it is an easy matter to illustrate concepts like altitude, azimuth, hour angle, and the angles of a spherical triangle. The ecliptic and mean sun can also be shown, thereby providing a good basis for demonstrating basic ideas and methods in the measurement of time. To what extent these and similar facilities are used in any given planetarium will depend largely on the demand. They should be of particular interest to sailors, yachtsmen, pilots, surveyors and students of astronomy. At a more popular level, its highly instructive to watch the planetarium sun move along the ecliptic and/or through the constellations of the zodiac. By compressing time so that the events of a year occur in a matter of minutes, and by keeping the sun on the meridian, the sun is seen to swing up and down the meridian as the seasons progress. The movements demonstrate in a most striking way the significance of the equinoxes and solstices, and the precise way in which the earth revolves around the sun. Alternatively, the planetarium sun can be kept permanently below the horizon, thereby bringing about a state of perpetual night. In this way the changing aspect of the night sky as seen from Toronto or any other place for the period of a whole year con be shown.

Variety with Integrity

Constellation figures, eclipses of the sun and moon, the phenomenon of the harvest moon, artificial satellites, space probes, comets, the precession of the equinoxes, the motions of the planets about the sun, sunspots, meteor showers, star clusters, nebulae, galaxies… these and many more things can be seen in the planetarium. In fact, anything that pertains to astronomy is appropriate material for presentation in the star theatre. Yet it would be comparatively easy to produce a series of spectacular although completely unrelated effects. The stately panorama of the starry skies could be paraded as a meaningless jumble of events. Sun, moon, and planets can be made to career across the dome in a fantastic way, the precessional cycle of 25,800 years can be compressed into one and a half minutes, and eclipses and constellation figures can be made to order by flicking appropriate switches. These things, however interesting in themselves, must be presented in context, that is, in their proper places and with suitable introduction and straightforward explanation. Only by exercising restraint and due care can astronomical events in the planetarium be invested with meaning and presented with integrity.

Many large-scale planetariums are not just a theatre of the skies. Exhibits and displays in the exhibition areas supplement the demonstrations given in the star chamber. A reference library and information centre enables books on astronomy, star charts, star atlases, moon maps, and astronomical photographs to be studied at leisure. In the basement a lecture room capable of seating dozens of people is usually available for meetings, courses, and special lectures on astronomy. Also optical workshops are usually operated in the building, where members of the public, at relatively low cost to themselves, can grind, polish, test their own telescope mirrors under expert guidance. A sales desk offers literature on astronomy to suit almost every need, particularly books for children, photographs of astronomical objects, seasonal star charts, star finders, and literature about exhibits, facilities and future events…