Observing Runs: Alone With the Night Sky

Most people have a very specific mental picture of what an astronomer is like. The word brings up images of serious, flannel-clad professors and students performing arcane rituals over mysterious contraptions of computer electronics and steel, giant telescopes swinging slowly through the darkness to probe the secret depths of the universe.

I used to love this image when I was a student, before I'd actually ventured out to an actual observatory. I liked the nobility of the stereotype, which bore more than a passing resemblance to the wizard-scholars in my favorite fantasy novels.

In truth, astronomers spend very little time physically at observatories, and to my knowledge, no one actually looks through telescopes anymore (human eyes are far less sensitive and accurate than computer chips). Astronomers have lost the art of telescope use to such an extent that almost all the best observatories in the world increasingly use professional technicians to collect the data, keeping clumsy astronomers at a safe distance from the delicate instruments.

There are real advantages to this state of affairs (you get your data emailed to you the next morning without having traveled long distances and lost sleep), but like most technological advances, something subtle and lovely is being lost. I can honestly say that the nights I've spent at telescopes were the times I most felt like a Real Scientist. For many cold, clear nights, I was perched on top of mountains, making real, if minor, discoveries.

First of all, astronomers aren't allowed to just turn up at an observatory and commandeer the telescope. Time on large telescopes is precious, and competition is fierce. All major observatories have "time allocation committees," panels of scientists who decide whether or not an astronomer's experiments are important and well-thought-out enough to warrant observing time.

For older but still-functional telescopes, about half the astronomers who apply are accepted. For the best telescopes in the world, it might be one out of ten. The committee has total control. You might ask for seven nights and be awarded three. It's very much like an audition, complete with the angst of wanting and not wanting to open that slim white envelope that's just arrived in your mail from the selection committee.

Well before you leave for the observatory, every last second of your time is planned out and a "script" created. Even a single night at a major telescope might cost the equivalent of tens of thousands of dollars in equipment and staffing costs, so wasting time is considered very bad form. The exact position in the sky of each of your objects is carefully calculated, as well as the time it raises and sets in the local sky. That way you know, without hesitation, which object to look at next. Reasoning skills can take a beating late at night at high altitudes, so following a script you've written out months before is essential.

But despite the seriousness of what's called an observing run (the data you take may, after all, determine whether or not you get your Ph.D.), I've always looked forward to them as a chance to have some fun.

I love observatories. The first major telescope I observed at was the four-meter at Kitt Peak National Observatory in Arizona. I still remember driving out across the high desert from Tucson, rounding a turn on the steep mountain road and catching my first sight of the pristine white domes of the observatory.

No matter how many times I've been on observing runs now, there is always this catch in my breath when I get my first glimpse of the dome. There's just something about large dome-shaped buildings. They're unconventionally beautiful, after all the boxes we normally live and work in. I find them intrinsically inviting.

I love the smell of large telescopes. As soon as you step in the door, there's a subtle odor of dust and industrial lubricant. It seems strange to say I like that smell, but it's oddly comforting, along with the gentle vibration of the gears and drives deep in the mechanism of the telescope. These things are huge beasts, and yet so delicate.

The Hale telescope at Mount Palomar, which I have also used, is almost twenty feet across, and as tall as a four-story building. But even weighing many hundreds of tons, it can still be guided by a single human hand (now you see where the industrial lubricant comes in). The inside of the dome at Palomar is almost exactly the same size as the Roman Pantheon, which seems to fit, as I always get the feeling I'm inside a cathedral. I'm not the only one; tourists drop their voices and shush children as they come in. Somehow, these giant metal and glass tubes seem to have a soul, and everyone feels that.

These days, telescopes are extremely easy to use (which is why astronomers aren't really required anymore to make the observations). Using a computer keyboard, you simply type in the celestial coordinates of the object you want to observe. The telescope automatically swings around and picks it up, and then begins to track it against the Earth's rotation. You tell the computer how long you want to look at the object, and then pretty much sit back and try to stay awake.

All the details are handled by observing assistants, people who work (and often live) full-time at the observatory. I've often thought these individuals are the true heirs to the astronomical tradition. They know the telescopes and the night sky far better than "professional" astronomers, and they often make significant personal and professional sacrifices for their jobs. Since observing assistants rarely have doctorates or publish papers, they are considered somewhat low-status members of the astronomical community. But like secretaries, these are the people who keep the whole business running. They are astoundingly competent, and the last people you ever want to get on the bad side of.

In some cases, these people have saved my professional career. When I was using some telescopes in Australia, a family of huntsman spiders decided to take up residence in my spectrograph. Now, I'm not the "girlie-girl" type, and I'm not even especially afraid of spiders. But to give you an idea of what I was up against, huntsman spiders get their names from the fact that they don't build webs, but instead chase and pounce on their prey, usually small birds.

Picture a very fast tarantula with long legs. Every once in a while, starlight beamed from the telescope into my spectrograph would mysteriously go dark, as one of the spiders decided to settle down take a nap in the light path. An observing assistant named Simon Chan, GOD BLESS HIM, would go and fish the beasties out.

But aside from a few moments of panic and lots of general frustration when instruments and weather were uncooperative, observing runs have given me some of the most memorable moments of my life. In some cases I really have felt like a wizard. When I was doing spectroscopy, I used to adjust this piece of metal called a "decker" very carefully every night. To this day, I have no idea what a "decker" does.

And there are also moments of surpassing drama, tempered by the perspective of just how vast the universe is. One night I was up at the telescope, waiting for two stars to rip each other apart. Locked into orbit around one another, I had calculated that they would sweep by each other too close for comfort, sending shocks and streamers of super-heated plasma careening into space.

I remember looking down at my watch, with twenty minutes to go until the event, when the thought dawned on me: just how long ago had this event actually happened? The stars were so far away that it must have taken quite a bit of time for the light from this event to reach the Earth, and my waiting telescope. A pocket calculator revealed the answer. And so I pulled up a chair, put on a pot of tea, and was the only person on the Earth who watched a solar system rip itself apart, about the same time Chaucer was writing the Canterbury Tales.

After everything had finished, I shut the telescope down as dawn rose over damp, eucalyptus-scented mountains, and walked home to bed, carefully avoiding sleepy kangaroos that had settled on the observatory lawn. I watched a blazingly bright full moon set below the horizon and thought about those doomed stars far away. At that moment I discovered what science has the potential to be on a personal level. Something you can only feel after enough time alone with the night sky.