Starry Nights

A favorite daydream of mine is to imagine historical figures in the present day. I suspect the shock they’d experience would come in three forms. The most obvious would be the change in technology. Imagine the shock of a helicopter or the magic of air conditioning. Smart phones combine so many technologies that I’m not sure someone from even 200 years ago could comprehend them.

Second would be the change in culture and society. Language, interpersonal relationships, health, longevity, travel; so many aspects of modern society would bear little or no resemblance to what many people from past centuries would consider normal.

But more than anything, I think they’d be stunned by the way the modernity has altered and obscured the natural world. The size and scale of cities, the destruction of wilderness, and the abstraction of humanity’s relationship with nature would likely make the modern world seem like an alien planet. There are many examples of this, but the one I’ve been thinking about the most has to do with the night sky.

If you were to look up at a clear night sky, how many stars do you think you’d see? Thousands? Millions? Unless you’re in a very dark, very remote place, you might only see a few hundred. And in a city? Maybe a couple dozen. It takes a trip to the country, away from city lights, to see the magic of the Milky Way.

This, of course, is a fairly recent phenomenon — and a sad one at that. The stars provided not just endless beauty, but also a source of mythology and a map for navigation.

I’m trying to recapture some of that majesty through my MIT class. And it’s embarrassingly difficult. Memorizing even a couple dozen stars and constellations is taxing my middle-aged brain. (H.A. Rey’s book, The Stars is a wonderful aid, and I love seeing Curious George-like illustrations helping me make sense of the heavens.) Yes, I know Orion, of course. And I can find Polaris, thank you very much. A few others, too. But they’re vastly outnumbered but what I fail to recognize. Part of the problem, of course, is that few are visible from populated areas, so we never have a chance to learn them.

The Boston skyline, as soon from an MIT rooftop, is brightly lit. Only the brightest stars can be seen from the city, if the sky is clear.

The class is structured in two major parts. In the classroom, we review the major stars and constellations, and develop an understanding of astronomical terminology, including coordinate systems. Then, weather permitting, we head outside to the roof. We started, at first, by drawing the night sky. Or, thanks to Boston’s bright lights and cloudy skies, the night skyline.

Notes and an early (and weak) sketch from my observing notebook.

Most sketches of the night sky are in negative. That is, you sketch the stars as dark objects against the paper’s white background. That’s not too difficult when looking only at the stars, but it gets significantly more challenging (for me, anyway) when drawing objects like the moon or the skyline. I found that I quickly lost track of what’s in reverse and what’s not.

Adding to the difficulty are the conditions. It is nighttime, of course, so light is in short supply. As is heat. Before venturing out to the roof, I would put on long underwear, an extra sweater, hat, scarf, and heavy gloves. Not ideal conditions for high-quality sketching.

After practicing sketching one class, we hauled out the small telescopes the next. Thanks to heavy cloud cover, we resigned ourselves to hazy views of the moon and close-ups of distant buildings.

On a clearer night, we broke out the cameras. As photograph literally translates to “light writing,” nighttime provides a challenge. How can you draw with light when there is little or no light to be found?

To give the students an opportunity to learn their cameras and how to work with limited light, we met up with the Boston Jedi club.

After the Jedi exhausted themselves, we aimed the cameras skyward. Hazy skies and city lights made all but the brightest skies invisible. But there, standing tall over MIT’s campus was Orion.

Orion makes its presence felt even on a hazy evening. Its three-star belt hovers nearly in the middle of the image. (Click for a larger photo.)

Let’s face it, astrophotography in the city is not ideal. Luckily, MIT owns an observatory about 35 miles to the northwest of Cambridge. The Wallace Astrophysical Observatory might not be the darkest place in the world, but it’s a whole lot better than Cambridge.

The observatory has six permanent telescopes. Two telescopes (one 24-inch and one 16-inch) sit under retractable domes, and four 14-inch telescopes sit under a retractable shed roof. And, of course, students can bring smaller telescopes.

After several weeks of cloudy weather, we caught a clear night during a trip to the observatory. I set up two cameras — one pointed toward Polaris, and another toward Orion. Each camera was set to take a six-second exposure once a minute. I let each run for about four hours.

Why take hundreds and hundreds of the same shot? The answer, of course, is that the shots aren’t the same. Not exactly. As the cameras snap away, the Earth spins on its axis and the stars appear to change position. You can’t notice it by watching, but over time the constellations slide across the sky.

Back home, I processed the images to remove the red and to draw out the colors of the night sky. Then I used software to combine the hundreds of images into a single “star trail.”

These images were taken directly with the camera. But it’s also possible to mount the camera to the telescopes themselves. Using an adapter, the camera body attaches to the telescope, which essentially becomes the camera’s lens.

Suddenly, stars that were distant or even invisible loomed large.

Tracking motors gently move the telescopes as the Earth spins under the stars. That keeps the objects in the field of view, and allows long exposures to stay focused on the stars.

As it got later and colder (thankfully I had put on long underwear, jeans, snow pants, long-sleeve t-shirt, Irish cable-knit sweater, hoodie sweatshirt, goose-down coat, scarf, hat and gloves), I decided it was time to pack it in. Then I spotted a bright dot peering through the trees.

It was Jupiter, rising slowly over the horizon. I waited for it to clear the tree line and aimed my telescope right at it.

Jupiter and four of its 69 moons: Io, Ganymede, Eruopa and Callisto.

Although it doesn’t quite come through the image, through the telescope itself you can just make out the cloud coloration on the planet.

As I stood there marveling at the sight, I started thinking of historical figures again. One in particular.

Galileo was the first person to see these four moons of Jupiter. He had built a telescope for himself and trained it on the heavens, discovering not just Jupiter’s moons, but also Saturn’s rings, the moon’s craters, and Venus’s phases.

More than 400 years later, some of us still marvel at what telescopes can reveal. If only our night skies sparkled like those of the 1600s.

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