Friday, August 10, 2007
Last night I saw this:
The ‘Great Cluster in Hercules.’ M13. It’s a globular cluster of stars within our galaxy the Milky Way.
Globular clusters are groups of thousands or even hundreds of thousands of stars grouped together, bound by gravity. They exist within galaxies. They are mostly older stars and the clusters themselves orbit as a group around the central ‘halo’ of stars making up the center of a galaxy.
Of course, the above pic is a long, time exposure taken with a very large telescope. What you see in real life looks not much like that. I saw it through binoculars. Imagine a tiny, less-contrasty version of the pic at right. M13 in binoculars under so-so suburban skies looks like a tiny hint of a gray smudge, but along the edges of the gray smudge there are little, fleeting shimmerings, tiny pin-points of white that you see and then don’t. Globular clusters have a distinctive look in small optics. There’s a smaller cluster, M4, visible in Scorpius.
Getting bit by the astronomy bug doesn’t result in a fever that’s debilitating, sapping strength. Rather, when you get bit by the astronomy bug the result is a kind of low-level, simmering, healthy fever that gives you an extra kick of heat, a little bit of extra energy that it takes to look around and pay attention to little things that turn out to be really beautiful, little things that lead to learning all sorts of odd facts about the universe around us.
There’s one other part of astronomy I want to finish off the week with.
It’s very easy to picture astronomy as a solitary activity. People alone in the dark, looking up, staring at things other people can’t see.
And that’s part of it.
But astronomy is a very social activity. Amateurs and professionals interact with the public, often setting up telescopes on sidewalks to show-off celestial wonders. Amateurs interact with professionals doing things like variable star observing, comet hunting and nova hunting. And everyone interested in astronomy gets together sometimes at gatherings called ‘star parties.’ People set up telescopes—often scopes they made themselves!—and spend a night sharing views and observing experiences with other amateurs and professionals.
(Indeed, professional astronomers usually get a kind of grimace from professional physicists, because amateur astronomers typically build well-made telescopes, stay informed about science and enjoy getting together for an evening of conversation and viewing, whereas amateur physicists typically build perpetual motion machines, know almost nothing about science and always seem to be about two sentences away from throwing a punch.)
I’ve been to star parties, but one thing I haven’t done yet but always have wanted to do is attend a Messier Marathon.
You may have noticed that most beautiful objects in the sky have a name and a number. The Ring Nebula is called M57. The Great Cluster in Hercules is M13. The smaller cluster in Scorpius (one of them) is M4. The ‘M’ stands for Charles Messier, a French astronomer from the eighteenth century. He used to hunt for comets and, to make his searches easier, he compiled a long list of sights in the sky which can look like comets but really weren’t comets. His list eventually contained 110 objects that he regarded as annoying [!] because they distracted him from his nightly searches.
Now, two hundred years later, the ‘Messier Objects’ are prized sights, and many people build a ‘life list’ of how many they have seen, what the conditions were when they viewed them, what kind of scope they used and so on.
And, of course, sometimes Messier Objects become a kind of friendly competition, in Messier Marathons. People set up their equipment, plot out the night’s sequences of observations, and try to view all 110 Messier Objects in one night. The really skillful people sometimes add a level of difficulty and try to do it all from memory, without using a star atlas or fancy drives that track down objects from a computer database.
I’ve never been to a Messier Marathon and I’ve never owned a telescope that could be counted on to see all 110 objects under ‘normal’ skies (and I’ve only seen about a dozen of the 110 sights!), but I’ve been bitten. I’ve got the energy and I’ll be getting around to the rest of the Messier Objects and, someday, I’ll grab them all in one night at a Messier Marathon.