Fall 1997

Looking Up

Arthur Babcock

Arthur Babcock is another avid amateur astronomer, and volunteers on the Friends of MIRA Steering Committee and at the MIRA office. He recently retired north to pursue mountain biking and dark skies from Los Angeles, where he taught French Literature at USC. His "Looking Up" column will be a regular feature.

The Great Non-Comet of 1991

The extraordinary series of comets we have had in recent years (Shoemaker-Levy impacting Jupiter in 1994, Hyakutake in 1996 and Hale-Bopp in 1997) underscores a fact that is often unappreciated by the general public: it is amateur astronomers who make most comet discoveries. On every clear night, scores of backyard enthusiasts scan the skies for new visitors to the inner solar system. Enormous dedication and perseverance are often required before these efforts are rewarded: it took Don Machholz 1700 hours of observing to find his first comet, and another 1742 hours to find his second. Every time a success is reported, the pulse of amateurs everywhere quickens a little at the news that one of their number has made a significant contribution to astronomy.

Sometimes, however, the pulse quickens a little prematurely. In February of 1991, I was doing some casual stargazing with several friends in Lockwood Valley, California. All of a sudden my friend Gene said, "What's that?" We all turned our heads to the southeastern sky where he was looking and saw a large, glowing, nebulous patch, clearly visible to the naked eye and obviously not a cloud or any known celestial object. "That's mine!" cried Gene, "Comet Hanson!" I began thinking furiously, trying to remember how exactly one goes about reporting a comet discovery. In the back of my mind, no doubt, was the thought that if I were the one who coordinated the reporting of this object, it would forever be known not as Comet Hanson, but Comet Hanson-Babcock.

Fortunately, there was no telephone nearby with which to report our find, and we turned our attention back to our "comet" in time to see it engage in some very uncometlike behavior. First, it rapidly changed shape: from a large, circular patch, it stretched out into a long, thin line reminiscent of a spiral galaxy seen edge-on. Not too long after that, the glow dissipated completely, and with it our dreams of scientific fame: this was no comet.

After some discussion, we realized that what we had seen was a cloud of barium gas, released by a satellite in earth orbit as a means of studying the solar wind. I am not sure which of us first came up with the correct explanation, but it doesn't matter-they don't name barium clouds after their discoverers.

Still, it was quite a sight to see, unlike any other. The cloud itself was rather beautiful, and the thrill of "discovery," even if short-lived, took the chill off a cold February night.

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