Thursday, September 25, 2008

“The Ancient Art Of Knowing The Sky”

There are a lot of specific astronomy topics I’m interested in. The outer system. Planet formation. How small can a star be? Plasma universe topics.

In the most general sense, however, there are two kinds of social aspects of astronomy that I think about a lot. At some point in the future I’ll be posting more about both of them. Today I’m just going to introduce one of them. (The second topic is the way astrophotography has seemingly come to dominate amateur astronomy. I don’t know if that is really true or if it is only the impression I get from magazines and the net. I’ll be posting more later on the way astrophotography seems to have taken over astronomy.)


Today I’m going to talk about what Bob Berman has recently called ‘the ancient art of knowing the sky.’

I’m going to tell one story from my own past, and then post a short excerpt from Bob Berman’s column in the current (October) issue of Astronomy magazine.

This pair of anecdotes is about a pretty big change in the world of astronomy. It’s futile to fight the future. It’s futile to be sad about how the young are different from the old. But, nonetheless, futility gets to us all. Sometimes.


About a year ago I described how a young woman grad student and I shut down and closed up an old observatory one weekend at Northwestern University. Before we closed up, we used the telescope to observe Saturn and the Pleiades. [Saturn and Titan, And The Pleiades ]

Today I’m going to describe how that young woman grad student and I got the observatory set up for the evening.

An astronomy professor was going to be giving a public lecture about Mars that night. (This was sometime back in the 70s. I was a junior high student at the time.) The old observatory wasn’t used for active research, just for public out-reach kinds of activities. Before the evening got underway, I helped his grad student get things ready.

“How high is Mars?” the grad student asked me.

I went outside and checked. “About fifteen degrees above the horizon,” I said. (If you extend your hand, fingers spread, from the tip of your index finger to the tip of your little finger is about fifteen degrees.)

“Should be high enough to get started,” she said.

She showed me how the old observatory operated.

First—if I remember right—we pulled some chains [!] which manually opened the shutters on the dome’s slit. Then we used a big hand-held control unit to press buttons that operated electric motors to rotate the dome counter-clockwise until Mars was visible in the east. Once the slit was positioned, the electric motors kept it slowly turning clockwise to keep Mars visible.

Then we used the hand-held control unit—connected to the observatory by a heavy cable—to press different buttons which slewed the telescope mount through right ascension and declination until the telescope was pointed roughly toward Mars. Then the grad student climbed up a platform [!] and used a guide scope mounted on the main telescope to carefully center Mars in the big scope’s field of view.

We both used the platform to look through the main telescope, focus and enjoy the view of the red planet. Once Mars was centered, electric motors in the mount kept the telescope tracking on the planet.

It was a pretty simple system and it worked reasonably well.

But it required the person operating the telescope to know the sky. You had to know where your target was in the sky and you had to know what it looked like to recognize it in the guide scope.

Back then, it never even occurred to me that this someday would be an issue.


However, even back then times were changing quickly. Telescope mounts soon would be completely computerized. Telescopes themselves soon would have eyepieces replaced by electronic cameras. As computers—so to speak—infested observatories it became less and less important for astronomers to know the sky.

And when knowledge isn’t required, people—certain kinds of people—lose the incentive to acquire that knowledge.


Not long after my pleasant experience at Northwestern, Bob Berman—then a young man but an old type of astronomer—began accumulating experiences like this one:

In 1980, the Indian government invited me to use its largest telescope, located near Naintal in the Himalayan foothills. A staff astronomer accompanied me. I was visiting for fun, not research, so I suggested some visual targets, starting with the Trapezium sextet of stars in Orion.

The 40-inch Cassegrain whirred and slewed, the dome rotated, and then everything stopped. My host peered into the eyepiece, and peered some more. I gazed up through the dome’s slit and immediately saw we were nowhere near Orion. But was it my place to tell him he’d blown it? I stayed quiet. Turned out, a power failure earlier that day—which in India are as common as mangos—had thrown all the electronics into never-never land.

When he realized the problem, he thought all was lost. As in another observatory when the same trouble arose, the staff was reluctant to release the axes and manually find the object. To them, visually locating anything seemed as intimidating as hand-steering a spacecraft to the Moon. Gone was the ancient art of knowing the sky. But I diplomatically said nothing.

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