Astronomers tend to be a long-lived clan. Of course, there are the sad exceptions. John Goodricke was a deaf-mute Englishman who died in 1786 at the age of twenty-one. During his short life he studied the regular changes in the light of the star, Algol. He was able to explain the cause, that Algol and some others are double stars, one of which periodically eclipses the other. Even today he enjoys a lasting reputation in astronomy.

Most of the old-time observers of the heavens, however, were hardy, durable specimens of humanity. They had to be. The best "seeing," when stars and planets are most visible, occurs on the clearest nights. These tend to be the coldest nights, as the Earth's heat radiates away into space unimpeded by clouds. The early telescopes lacked the drive mechanisms and protective domes that we associate with modern instruments. Also, to avoid the form of image distortion known as chromatic aberration, the telescopes were often enormously long. The observers would crouch on the ground or perch high in the air, at one end of a two-hundred-foot long tube. They stayed there, hour after hour, waiting for the precious moments when the small-scale turbulence that causes stars to twinkle was at its least.

It does not seem to have done them much harm, and maybe it kept them away from more debilitating pleasures. William Herschel, who discovered the planet Uranus, was an active observer well into his seventies and wrote his last scientific paper when he was eighty-three. His sister, Caroline, who should be better known than she is as an early woman scientist, shared the labor of observing with Herschel and made her own share of discoveries. She lived to be ninety-eight.

Everything changed with the introduction of photography into astronomy, which happened by degrees between 1839 (Herschel's astronomer son, John, did some of the first work) and 1860, when the process became standardized. After that, observing in principle became a good deal easier. You could set up the telescope and the film to record for as long as you wanted, go to bed, and get up in the morning to develop the results.

Of course, you still had to examine those results. That could be a process at least as tedious as sitting at a telescope. Clyde Tombaugh discovered Pluto in 1930, after thousands of hours of work with a blink comparator. This uses photographs of the same area of the sky taken at two different times. By alternating rapidly between the two images, the instrument allows to you pick out what has changed -- a comet, perhaps, or even a new planet. It is work which called for attention and great stamina, but it did not do Clyde Tombaugh any harm. He died in 1997, at the age of ninety.

By the middle of the twentieth century astronomy was changing again. Observations of stars went on, as actively as ever, but there was increased emphasis on the processes going on inside those stars. As an undergraduate I remember the astrophysicist Fred (later Sir Fred) Hoyle appearing to give nine o'clock lectures unshaven, bleary-eyed, and clearly the worse for wear. Our speculations as to what he had been up were suitably lurid, even if we didn't actually believe them. In fact, he had been up all night at the computer, running through the detailed process of nuclear cooking (more technically, nucleosynthesis) by which heavier elements are built up from hydrogen and helium in the furnaces within the stars. Again, this called for hard and sustained effort. It did him no harm. Hoyle died in August, 2001, at the age of eighty-six, mentally and physically active until his last year.

While the theorists were at work, the observers found new ways to make life hard for themselves. The atmosphere had been a source of observational distortion since the earliest days of astronomy. The obvious answer is to get above it. You can put a telescope into orbit, which is what was done with the Hubble. Or you can place your observatory on top of a mountain, in a location where the air is already unusually thin and clear.

The first option allows the "observer" to be anywhere on Earth. Requests for observation time and target specifications are sent to the central programming facility for the Hubble, at the Space Telescope Institute near Baltimore. Then you sit and wait your turn. That might seem to be the rational choice, but it's not exactly hands-on and astronomers are not always rational people. Many astronomers seek the high observatories, like that on the top of Mauna Kea in Hawaii, 13,600 feet up, where visibility is outstanding but cold competes with the danger of altitude sickness. The road to the top is not very good. A few years away a storm washed out part of it. A group of French astronomers were stranded on the mountain for five days, living on cold water and Hershey bars.

In addition to the highest observation posts, we have other astronomers working sites deep underground. There, they monitor huge tanks of liquid (usually, a form of detergent cleaning fluid) for signals announcing the interaction of that elusive particle, the neutrino, with ordinary matter.

Why do they care? Well, it turns out that the number of a particular type of neutrino (they come in three varieties) that reaches us from the Sun is intimately connected with the question of the neutrino's mass. For many years it was believed that the neutrino had no mass at all. Now the particle is thought to indeed possess mass - but how much? The answer to this question is linked to the question of the total mass of the universe, which connects in turn to the expansion rate and future size of the entire cosmos.

From deep mines shafts, to the ends of the universe. Where will astronomy go next? Certainly, into space, which has its own hazards but which does away completely with those pesky atmospheric problems. Certainly, into ever more abstract theories and computer models. Probably, deeper and deeper underground.

Beyond that, I don't know. But if history is any guide, wherever astronomy goes, you might want to follow it. It is a good way to increase your own chances of a life both active and long.