ANJI, Zhejiang: Scientists from around the world were stationed in China Tuesday, all set to study today's much-anticipated solar eclipse, but their wait became tinged with worry as more and more clouds formed in the sky.
More than 130 scientists who have come to China for the event are gathered at a 1,000-m mountain in Tianhuangping, about 60 km from Hangzhou and 180 km from Shanghai.
The site was selected by Jay Pasachoff, chairman of the International Astronomical Union's Working Group on Solar Eclipses.
Most of the scientists arrived at Tianhuangping two weeks ago. And, they believe they have come to the right place.
Tianhuangping boasts that it has the best conditions for observing the solar eclipse.
It sits above pollution (smog is usually found below 900 m), which can obstruct a full view of the eclipse, said Professor Robert Lucas of the University of Sydney, Australia, who has joined the US' Williams College team led by Pasachoff.
"And since it is higher, it is physically cooler, which is good for the equipment; high temperatures can adversely affect equipment such as the telescope," said Lucas.
By Monday afternoon, everything seemed so promising that Siraj Hasan, head of the Indian Institute of Astrophysics, who also is leading a team in Tianhuangping, said with a broad smile: "So far so good."
Tuesday, though, the smiles were replaced by frowns - as the scientists looked skyward, glancing at the clouds that had formed, they worried that clouds may be a factor today.
Weather forecasts have predicted cloudy skies with a chance of thunderstorms for most of Zhejiang province.
The scientists have no backup plan if the weather disappoints them; it would not be possible to quickly relocate because alignment of their equipment takes at least two days.
And weather conditions at other locations, such as Shanghai and Hangzhou, could be worse.
"Clouds can be a problem because they reflect light, which will obscure the detail in the corona and make it hard to isolate single colors," said Bao Xingming, a researcher from the National Astronomical Observatory.
"But we will keep our fingers crossed. Nothing is harder to tell than the weather."