It's hard to think of a more favorable set of circumstances for a casual observer like Jim Stevens.
Yet despite having such a rare opportunity, the prize eluded him. And after the fact, other observers who were present say, Bopp and Stevens may have engaged in a little damage control to compensate for that heartbreaking fact.
Bopp's story that the comet had drifted into view--that Stevens couldn't see it because it hadn't come into the picture yet--is one his fellow astronomers don't buy.
They say the comet was practically right on top of the globular cluster M70, and both easily fit into a telescopic view, even at the magnification Stevens and Bopp were using.
Really, there were tens of thousands of light-years between the comet and the cluster, but they were lined up in the sky so that from Earth, only a small angular measurement separated them--only 13 arc minutes, in fact, or about half the apparent diameter of the full moon.
When Bopp draws a picture of what he saw, he places M70 on the right side of the field, near the three o'clock position. He puts the comet at the extreme opposite edge, with both objects just fitting in the telescope's circular field of view.
But astronomers who were there that night say that isn't consistent with how much sky Bopp could see in Stevens' telescope.
Stevens himself confirms that with the telescope's configuration of mirrors and the particular eyepiece they were using, the field of view would have been about 48 arc minutes across, enough area to show the entire full moon and then some.
Both objects--M70 and the comet--should have fit in that field of view with plenty of room.
"I really believe that Tom has subconsciously--that he wouldn't do it consciously because he's such a nice guy--that he's subconsciously decided that that's what happened, even though some of us--and the orbital elements--say otherwise," says one of the observers who was present, and who asked not to be named by New Times.
If Bopp's widely reported story of the comet "drifting" into the field of view was intended--consciously or otherwise--to save Stevens embarrassment, it didn't address another side of the question: why Stevens didn't see the comet when he first located the globular cluster using a low-power eyepiece.
It was part of the Bopp-Stevens standard m.o.: Stevens had found M70 with a low-power ocular which would have shown a circle of sky well over a degree across. The comet had to have been in that field of view.
"Oh, yeah, it was in there," Stevens admits. But he says he's not surprised that he didn't see the thing, given the small size of the object and the lessened contrast of the low-power view.
Besides, he acknowledges, he was in a hurry. And he can't confirm Bopp's story that when Stevens plopped in the higher-powered eyepiece, the comet had not yet drifted into the field of view. The reason?
He never took a look. Stevens was too eager to get his friend over to use the telescope. And that's how he missed finding one of the largest comets ever discovered.
That night, however, there was little time to dwell on the fact that star-crossed Stevens--telescope builder, astronomy hound--had missed the chance of a lifetime.
There was work to do.
Their first step was obvious: Check star charts to make sure they weren't looking at a nebula or some other permanent feature. None of their maps showed an object near the globular cluster M70.
One more piece of evidence would confirm that they had a comet: movement. Even very distant comets (this one was 577 million miles from Earth that night) show a discernible movement against the background of stars over a period as short as an hour. Stevens says he perceived motion almost immediately, but the rest of the astronomers urged him to be sure. One of them, Bernie Sanden, made a drawing of the comet, using some dim stars nearby to make a quadrangle. An hour later, the quadrangle had noticeably stretched.
They were sure they had a comet.
Now came the most maddening step: notification. Getting credit for the discovery meant getting a message quickly to an obscure office in Cambridge, Massachusetts. There, a small team of astronomers acts as the world's clearinghouse for celestial discoveries. No discovery is official until that office--the International Astronomical Union, or IAU--says so.