Friday, April 27, 2007

Telescopes & People

I've made many discoveries in the past twelve years as a space advocate and astronomy educator. When dealing with a visually attuned public, you need visuals, be they videos, slide shows or models. The discoveries I made deal with the fragile nature of these items.
The first thing I discovered is that regular commercial model kits are far too fragile, the more detailed the more fragile. Many has been the time that a model of the space shuttle has returned to me with parts askew. So, I've resorted to making sturdier models.
The same is true of telescopes. Especially when one considers the costs of even a small telescope versus the costs of even a complex model (which is usually in the form of hours spent building it).
The problem is that even simple telescopes and their mounts can be sensitive affairs. True, it is pretty difficult to break a metal mounting bracket, but that isn't the real issue here. The real issue is that, aside from one telescope design, most telescopes are really not designed to be used in large group settings.
The most common telescope mount is the altitude/azimuth (or alt/az) mount. This is the one you'll find on most cheap telescopes and it provides the two most basic planes of movement; lateral and vertical (that is, side to side and up and down). For low power, this is an ideal setup. Their problem lies in the fact that the Earth is rotating; soon the object you have them aimed at drifts out of view. Simple fix; you simply move the telescope, right? Well, you end up moving it slightly in two different planes, but again for low power, this is fine.
Astronomers overcome this by resorting to another mount design, the equatorial mount. This allows the telescope to track objects by being aligned with the Earth's axis; its movements match right ascension (RA) and declination (DEC). Two stay on an object is simply a modest move towards the west. Many of these mounts are motorized and will stay on their targets when properly aligned.
It's that proper alignment that is the issue here. People are people and will want to move the telescope themselves, and in doing so might move it off axis, creating a problem in trying to keep an object on target.
What do you do in either case?
For a long time, I'd only take one telescope on my outings. That's great for basic Vagabonding. When I'm in a class setting, though, it gets trying, so several scopes have to be brought. To keep people from bumping into one another while using the instruments it is necessary to keep them fairly distant from one another. Example; one telescope might be aimed at the Moon, another aimed at Venus and yet another aimed at the Beehive Cluster. The distance between them should be better than ten feet. Sounds easy, but what usually happens is I find myself running from one instrument to another. Good exercise, at least!
Then, a visitor, in their desire to be helpful, turns the wrong thing, sometimes the focuser. I'm serious here, some people think that that will move the telescope, or that the previous person unfocused the telescope and that the target hasn't drifted out of the field but is simply extremely out of focus. In their frustration, they then start to move the scope itself around, pointing everywhere in an effort to find the object. Try as they may, it simply adds to their frustration, followed by the plaintive calls of "Mr. Little? We lost the target!"
But this is not really a grumble, for there are solutions. First, let them know that telescopes are sensitive by their nature and that if something does go wrong, simply call for the professional on site (me). Second, because there will be those who want to help, give a basic explanation of the parts of the scope; which ones they can touch, which ones they shouldn't ("you can move the scope if you want to, but please don't touch the focuser"). Third, and this is tied to the second point, make sure that finder scopes are properly aligned and explain its purpose before your viewing begins. Trust me here; I failed to do that on my last outing as I was running late. There were many very bright people in that group who could have done the job, but since I hadn't done mine, they couldn't help. Lesson learned; take time to make sure they are aligned. By following those rules, a group viewing can be guaranteed to be a success. Believe me, the teacher has been taught!
Now, what sort of telescope is best suited for large public viewings? The Dobsonian. Easy to use, easy to setup, compact mount (try transporting eight tripods in a minivan and you'll long for Dobsonians!), the Dobsonian is perhaps the best tool for the trick.
And I lack one.