"There hasn't been a single cloud in the sky all day," said Professor Jay Pasachoff of Williams College in the United States and leader of an international team of scientists who observed the African eclipse. The team had telescopes and cameras trained on the sun from the top of the Intercontinental Hotel in Lusaka and from the campus of the University of Zambia across town.
The group is studying the mystery of why the sun's corona, or gaseous atmosphere, is so much hotter than its core. Despite one glitch in one of the experiments at the university site, Pasachoff said the expedition has been very successful."We checked the data, and we're busy making copies now for safety," he said by cell phone. Although data crunching will begin soon, it will be a year or two before substantial results are available. So while the astronomers and physicists are analyzing this year's eclipse, they'll be starting to prepare for the next.
There was an element of chance as well as science in the success of the observations. Pasachoff''s group is working with, among others, colleagues at the Harvard-Smithsonian Center for Astrophysics and the Lockheed Martin Solar Research Group, who operate a telescope on a satellite called TRACE. The idea was to coordinate shots taken from space with those on the ground, yielding images and data richer than either vantage point could provide alone. Unlike the larger equipment on the SOHO satellite, the TRACE lens can see only a portion of the sun at a time - and the researchers' computers on the ground lack constant contact with the telescope's computers. So the decision about where to jointly point the cameras had to be made in advance, through email consultations.
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As it happened, there were not as many areas of good observation as conditions the previous day suggested. "Even though we're at the peak of the solar cycle," Pasachoff said, "the sun was relatively quiet today, and when we looked at the satellite images this morning, we could see that the solar corona was not very bright and that there were very few streamers. So though the magnetic field was typical of the maximum solar cycle, the corona was not at its very brightest."
Nevertheless, Pasachoff said, "we think we chose the right spots. But we had to make a decision yesterday, and fortunately we didn't choose the whole northern border of the sun, which was relatively devoid of corona."
Kathy Reeves, a researcher at the Harvard-Smithsonian Center, was also pleased. "Yesterday we wrote up an observing sequence for the eclipse and sent it up to the satellite," she said Thursday after viewing the eclipse on a television feed from NASA, the US space agency. "We had seen some nice coronal loops coming over the limb, or edge, of the sun, and we had to take into account the solar rotation to judge where to point." Far away from Zambia, with nothing left to do but wait and watch, she was able to judge her planning a success.
