The Role of the Telescope in the Planetarium
PO Box 198, Route 1
Chadds Ford, Pennsylvania 19317
There is a traditional but often-overlooked symbiotic relationship between "skyshow" presentations in a planetarium and seeing the "real thing" through an astronomical telescope of adequate aperture. This involves the best of man's ingenious efforts to faithfully reproduce the starry sky inside a theater, on the one hand, and confronting the original masterworks of the heavens face to face on the other.
I have had the opportunity of introducing tens of thousands of people to the stars using some of the largest planetarium instruments ever made, including the huge Zeiss Mark II and the Spitz Space Voyager. I've also had the privilege of showing like numbers the wonders of the heavens through some of the finest telescopes in existence, among them Celestron Schmidt-Cassegrains up to 56 cm (22 inch) in aperture, a historic 33 cm (13 inch) Fitz-Clark refractor and a 76 cm (30 inch) Brashear refractor (this last instrument being the fifth largest in the world).
This experience in "star hustling" (to use Jack Horkheimer's famous phrase) both the artificial sky and the real one leaves no doubt in my mind that the wonder awakened in a planetarium presentation must be complimented by firsthand viewing of celestial objects through a telescope for maximum impact. By this I mean a transforming and elevating personal encounter with astronomy that your students or visitors will carry with them for the rest of their lives.
In the March, 1990, issue of Sky & Telescope magazine, I contributed a one-page "Focal Point" opinion piece entitled "Metaphysical Stargazing." In it, I pointed out the subtle but very real and significant benefits to the individual of "communing" directly with the heavens through naked-eye, binocular and (especially) telescopic observation of its wonders. The enthusiastic response from amateur and professional astronomers, planetarium educators, science teachers and students (of all age levels) clearly showed that a resonant chord had been struck in these readers from around the world.
Among the benefits of "stargazing" covered in this article are the therapeutic relaxation, expansion of consciousness and spiritual contact that come with contemplative viewing of the cosmic depths. Central to all of this is what I like to call the "photon connection"-the incredible fact that when we look at celestial objects (be they a few light minutes away as in the case of the sun, or billions of light years distant for galaxies and quasars) we are in direct physical contact with them as the photons end their journey across space and time on the retinas of our eyes. A piece of something that was once inside of them is now inside us!
Realization of this profound fact helps explain the strange fascination we all seem to have with the stars, and how something so remote and beyond our reach can have such a lasting impact upon us. It also shows why the CCD/video imaging that's all the rage today-even given its attendant wondrous capabilities-simply doesn't "cut it." Looking at celestial objects on a TV monitor or projected onto a planetarium dome (even in real-time) cannot fulfill the need of the human mind and soul for that direct personal contact with the cosmos from which we sprang. As Eric Hoffer so well expressed it, "It's a kind of homing impulse-we are drawn to where we came from."
My premise is that providing an opportunity for first-hand telescopic encounters with the day or night sky as part of a planetarium visit is essential to any truly meaningful and lasting educational astronomy experience. In other words, every such institution-be it a large museum installation or small school facility-should have one or more good telescopes available (and scheduled) for regular use in its programming, weather permitting.
As to what size, type and make of instrument this should be, it really matters little so long as the optics are good and the mounting stable. Nothing so draws attention as an open observatory dome or a large telescope tube looming against the sky in the parking lot of a planetarium. The latter is especially true for the big Dobsonian reflectors that have become very popular with stargazers in recent years, looking for all the world as they do like some huge celestial cannon aimed heavenward!
My personal preference, from the standpoint of observer convenience, portability (if required), light grasp, resolution, field of view, image scale, and atmospheric and thermal considerations, is the compact Schmidt-Cassegrain catadioptric that is in such widespread use today. An instrument in the 20 to 35 cm (8 to 14 inch) aperture range (whether portable or permanently mounted) makes a superb teaching and entertaining tool for use at a planetarium. Few realize that given good atmospheric seeing (steadiness), such an instrument will show features on the moon's surface just a few hundred yards across and detail in sunspots only several kilometers in size! Likewise, on nights of good atmospheric transparency (clarity), scopes of this class are capable of revealing the nearest quasars-even from the heart of a light-polluted city!
I invite each one of you, as planetarians and fellow stargazers, to put this premise to the test by giving your students or visitors (plus staff and administrators as well!) a look through a telescope as the climax (its traditional function at most major planetariums in the past) to their encounter with the universe. Experience for yourself the wonder in their eyes, the excitement in their voices and the astonishment on their faces as they peer into space. You will then know beyond any doubt that they have indeed "connected" with the cosmos. And you will realize once again why you have made it your business and your mission to point the way skyward to all who will look and listen.
This paper was originally presented at the MAPS Conference in Baltimore, Maryland, in April 1993, and was first printed in the High Altitude Observer.
Reproduced from the Planetarian, Vol. 22, #3, September 1993. Copyright 1993 International Planetarium Society. For permission to reproduce please contact Executive Editor, Sharon Shanks.