Sunday, May 20, 2007

A Convertible for the Imagination

One item I left out of the eight things about myself is that my brother-in-law is a serious amateur astronomer, the sort with a backyard observatory holding a 14-inch telescope, and shelves of treatises on astrophysics and cosmology. A couple of nights ago I spent the night at his place to see his new CCD hookup, which produces - displayed incongruously on an old-fashioned looking TV monitor - shockingly detailed images of deep-sky objects.

An evening tour of spring galaxies was followed by a few hours' sleep, then a predawn tour of the summer Milky Way. I won't give a travelogue; there's no substitute for seeing them, and as with a road trip the particular sights count for less than the overall impact of landscape, or in this case of skyscape. Which leads me to the one great discovery I've made at Ron's observatory, which has to do not with the sky itself but with observatories.

A major design choice in building a backyard observatory is whether to have a slide-off roof or a dome. The slide-off is simpler, cheaper, and eminently practical for observatories on this scale. A dome, on the other hand, has sheer style and evocative power. No other science has such quiet drama to its daily practice as astronomy does: the dome's observing slot sliding open as twilight falls, revealing the first evening stars to the waiting telescope. We've seen it in a hundred documentaries; it never ceases to thrill. (In real life I imagine the dome only opens after dark, but compared to Hollywood spaceships this is the least of dramatic license.)

A dome, however, brings additional costs and complications: The whole dome has to revolve, and the observing slot has to open and close. With some regret Ron chose a slide-off roof. This turned out to be fortunate, because the slide-off roof turned out to have a vast unanticipate advantage - the starry sky itself.

A classical domed observatory actually gives only a quite restricted view of the sky, the gap left by the open slot; and much of that is filled by the bulk of the telescope. So long as you're looking through the telescope (or at an image produced by a CCD mounted on the telescope) it doesn't matter. When you look around, however, you're largely confined, with only a teasing glipse of the sky. A slide-off roof, however, reveals the whole dome of the heavens, while the walls block out local lights and conceal your mundane terrestrial surroundings.

The first time Ron slid back the roof on his observatory it was stunning, like being aboard a spaceship with panoramic viewports - or riding in a convertible with the top down, out for a spin on the celestial highway.

This experience also taught me a historical lesson. Observatories and telescopes are nearly synonymous to us, but people built astronomical observatories, sometimes quite imposing ones, long before the invention of the telescope. Other large instruments, such as Tycho Brahe's quadrants, also required a mounting and platform. Yet even though Catherine of Lyonesse has a scene at an observatory inspired by Tycho's, the logic of pre-telescopic observatories still slightly eluded me. It seemed a bit like building a freeway when you don't have a car.

Now I understand: The simple act of providing yourself with an observating platform, separated from its surroundings but open to the sky, has a powerful mental focusing effect. It is just you, face to face with the visible heavens, that cathedral immeasurably vaster and more mysterious than any wrought by men.

Because we all need a little vastness now and then.


Anonymous said...

For those of us who are tech challenged and we are legion, what's CCD (other than Collapsing Colony Disorder)or a CCD?

Envy you the experience, btw.


Rick said...

Oops. Charge-coupled device, which doesn't really mean anything either, does it? Basically like a picture element in a videocam, which is why we were looking at the Eagle Nebula on a TV set.

The nifty thing is that it averages out 30 seconds (or whatever) of atmospheric jitter, allowing it to catch incredibly fine detail. There's an interesting tension between the prettiest, most aesthetic setting, and a slightly more overexposed setting that brings out fine details.

Nyrath the nearly wise said...

One of the differences between science fiction and rocketpunk is the amplified sense of wonder. So your observations about observatories are right on target.

Kedamono said...

When I was a kid, round about 1975 or so, I got one of those cheap KMart telescopes. (There was no way I'd get one of those nice reflectors, too pricey.)

In the summer, late at night, I'd down to our floating dock on the lake and setup the telescope and after checking out a couple of windows, (I was 15 at the time :-) ), I'd start looking for planets like Jupiter or Saturn. There I was, seeing the rings of Saturn or the moons of Jupiter, or the salmon red of Mars.

I'd spot a globular cluster and be amazed at all the stars. Or just looking at the bright smudge of the Orion Nebula, wondering how it would look with a bigger scope. There was no roof, just me and my 'scope.

The only other time I really got a sense of wonder about the starry sky was when I was in the army on maneuvers. We were only 20 miles from Trinity, and hundreds from any light pollution.

And you saw stars. You saw what the ancients saw, in all their glory. It's something everyone needs to do, get far, far away from civilization and just look at the stars, and wonder.

Bernita said...

Yes, away from light pollution, the night sky is a wonder, even without a telescope.

Carla said...

I envy you the experience too. I used to be keen on astronomy as a kid, and I remember the night sky as magical even in a town environment cluttered up by streetlights and the neighbour's hedge.

Light pollution is a modern problem, as far as I know, but the observatory in ancient tims would have had the practical effect of providing an unencumbered view of the sky and the psychological effect of being a specific place for a specific activity, separate from the everyday world. Presumably it's the origin of the long-standing association between wizards and towers (ivory or otherwise)?

Anonymous said...

I have the good fortune to live in the country, so the night sky isn't too badly light polluted. Half moon tonight just beginning to set.

I always make it a point to wave at one of the stars. You never know; someone out there may be looking in our direction.

Rick said...

One of the most amazing things that people don't realize is just how much you can see without a telescope or even binoculars. In fact the naked eye is really the only way to look at the sky as a whole.