A?guidebook for observing the July 22 solar eclipse written by three Chinese teenagers has been commended by Jay Pasachoff, head of the Solar Eclipse Working Group of the International Astronomical Union.

"They provided detailed information for astronomical researchers and lovers all over the world," said Pasachoff, who visited the students' school in Hangzhou, capital of east China's Zhejiang Province, on Tuesday.

The professor said he will watch the scene at one of the 23 sites recommended by the Chinese students in Tianhuangping, Anji County, Zhejiang.

World astronomers have predicted that the July 22 total solar eclipse will be seen for 6 minutes 30 seconds in India and China.

Wang Sichao, an expert with the Purple Mountain Observatory of the Chinese Academy of Sciences based in east China's Nanjing City, said the total eclipse will be the longest of its kind in 141 years and will be seen from 42 cities in China's most populous Yangtze River Valley.

"The number of people watching the solar eclipse will make a historical record, since previous solar eclipses could only be best observed in desolate regions," said the expert.

The three Chinese students of the Hangzhou Senior High School started their project two years ago. They traveled 1,400 kilometers along the predicted solar eclipse route in China with GPS devices, and selected the 23 best observation sites.

Pasachoff said the guidebook with star-rankings for items such as site, photographic conditions, transportation and accommodation was adopted by IAU and other astronomical organizations.

Like Pasachoff, world astronomical enthusiasts booked hotels in the recommended sites in the guidebook as early as 2007.

"They have done a wonderful job!" said Pasachoff.

"Eclipse-observing groups from India, Japan, Sweden, Denmark and Germany have chosen their observation sites based on our recommendation," said Lin Lan, the students' supervisor.

"We felt like we are the host to receive friends to watch the eclipse. So we strived to come up with a comprehensive evaluation of the sites to help visitors enjoy a safe and fruitful trip," said Cai Tingni, one of the three students who wrote the guidebook.

(Xinhua News Agency July 16, 2009)