The ’51 Observatory: a new view of the sky

A nerdy confession: In elementary school, I admired Maria Mitchell—the first astronomy professor at Vassar College, an astronomy enthusiast and the discoverer of a comet—so much that I donned an 19th-century costume and played her in History Club. After taking Professor of Astronomy Debra Elmegreen's Life in the Universe class as a doe-eyed freshman, I decided to upgrade from an eight-inch, reflecting telescope I had used to scan the skies as a kid and work at Vassar's Class of 1951 Observatory. You might have taken a wrong turn on a running trail or gotten lost trying to find Walker Field House and stumbled upon a gray building that looks like a grain silo. In fact, the observatory is the home to the most powerful telescope in New York.

Part of my job as a laboratory assistant at the Vassar Observatory is to lead tours of the facility every Wednesday at 9 p.m.—but be sure to call ahead of time if you're interested. A large portion of my job is to demonstrate how to use equipment in the observatory, particularly the telescope. Telescopes have come a long way technologically; scientists, perched on a basket high above the ground to monitor the instrument, used to spend eight hours freezing in pursuit of observation. (There's an old joke that astronomers would bring up a thermos of coffee and return with the thermos full…of something else.) Students were treated like work horses and had to operate a labor-intensive, complicated pulley system to move both the dome and the telescope. Luckily, Vassar's building boasts a convenient warm room and a computer-operated system that guides both the movement of the telescope and the rotation of the dome (although it's still very squeaky). I can speak from experience: After a long trek from the Town Houses, having run into a herd of deer on the pitch-dark path up to the Observatory, it's actually quite pleasant to make oneself some coffee and open the dome. Here's how I do it: First, I turn on the telescope, of course. I boot up the computers, open the mirror doors (which focus the light from distant stars) and discontinue the halt of the motors (which control the dome). When I open the dome, it looks a little bit like an alligator jaw biting into the night sky above. At this point it's always a struggle not to be alarmed by the horrendous screeching noise this makes, but I always try not to fall off the ladder in surprise. Note to self: Turn the lights back off on your way out—many times, observatory workers forget to do this and nullify all that night's images!

Imagine you're the laboratory assistant. In the comfort of the warm room, send the telescope to a bright star; perhaps, Deneb, a star in the constellation Cygnus if it's summertime. As Deneb is bright, you'll only need to take a short exposure, say one-tenth of a second, for an image. Because the telescope settles, kind of like an old house, the focus won't always be the same. Adjust the focus, and dither the telescope slightly in order the center the star in your picture.

Finally, you're ready to "do" some astronomy. If you're of Elmegreen's school of thought, galaxies are really the only objects worthy of an astronomer's attention. Navigate—in observational astronomy this is called "slewing"—the telescope to the Andromeda galaxy, our own Milky Way's neighbor (although it's still two and a half million light years away). Unlike other galaxies, which are zooming away from us as the universe expands, the Andromeda galaxy will crash into the Milky Way in two and a half billion years.

Maybe you're itching to look at a galaxy really far away. In the summer of 2007, Vassar Undergraduate Research Summer Institute students studied the light curve of a blazar called BL Lac, whose claim to fame is the its status as the "original blazar." Blazars are part of an astronomical class of objects known as active galactic nuclei (AGNs), billions of light years away, that give us an interesting picture of our early universe, which began about 14 billion years ago. That means a massive black hole in the middle of an AGN blasted out bipolar twin jets of charged particles near the speed of light; billions of years later, the photons from this spectacular event reach Vassar's telescope and your eye if we aim it just so.

You could also track the very reliable pulsars, the ghosts of a massive star after its death. Pulsars emit jets of electromagnetic radiation at regular intervals. After being discovered by Jocelyn Bell Burnell in 1967, these astronomical objects, because of their alarmingly reliable emissions, incited a frenzy of alien hunters and dreams of little green men sending signals to Earth.
If you go to the observatory in the winter, at about 7 p.m., Jupiter is spectacular, surrounded by a pretty host of its four main moons—Io, Europa, Ganymede and Callisto. All discovered by Galileo in 1610, you can see them the way he did 400 years later in breathtaking clarity. Jupiter's giant red spot—a gigantic, churning storm three times the size of Earth's diameter—is also visible, and appears misleadingly calm and majestic. Push the telescope to Saturn, another gas giant. Most impressive, you can see Saturn's rings—delicate structures of ice, gas and dust. Although you can't see more delicate features, there are actually moonlets embedded in these gargantuan rings.

But there's no reason to stop at Saturn. There's no reason to stop at all, for that matter. The sky has always been a source of awe an wonder; humans ache for contact with another civilization in this vast void. Using advanced technology right in Vassar's backyard, we can measure these photons and gather knowledge about the universe of which we are a miniscule part. Wednesday nights at the Vassar Observatory are your chance to explore a frontier that will never close—weather permitting of course. There's literally no end to the night sky, which is good news for everyone from the seasoned observational astronomer to the student who simply wants a glimpse at something at once familiar and endlessly mysterious: the universe.