The longest total solar eclipse of this century has triggered tourist fever along China's Yangtze River Valley as astronomy enthusiasts from home and abroad flock there to watch the event on July 22.

People set for the eclipse viewing in an observation station in Hankou, Hubei Province, on July 20, 2009. The longest total solar eclipse of this century has triggered tourist fever along China's Yangtze River Valley as astronomy enthusiasts from home and abroad flock there to watch the event on July 22.

The total eclipse, which lasts as long as six minutes 43 seconds, will be visible along the river valley on Wednesday morning.

Wang Sichao, an expert with the Purple Mountain Observatory of the Chinese Academy of Sciences based in east China's Nanjing City, said the eclipse will not be surpassed in duration until June 13, 2132.

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

The total eclipse is expected to begin between 9 a.m. to 9:38 a.m. (Beijing Time), the expert said.

Viewers in Chinese regions beyond the river valley, including Beijing, can observe a partial eclipse, he added.

The National Astronomical Observatories has recommended eight sites in eastern China that the agency believes are the best places to view the event.

Among the sites is Jiaxing, a city in Zhejiang province.

All the hotels and inns in Jiaxing are fully booked by eclipse watchers, 6,000 of whom traveled from abroad, said Zhou Hongxia, deputy director of the local tourism administration.

"The number could be much bigger on Wednesday," she said. "Many of the watchers started to book rooms more than a year ago."

The city is under severe pressure as it strives to accommodate the influx of visitors, traffic, emergency care and translators.

Local authorities are also working to ensure against A/H1N1 flu outbreaks and to avoid traffic jams and stampedes.

Nearly 3,000 astronomy enthusiasts from Japan, the United States and Europe have also flocked to central province of Hubei, the provincial tourism administration said Monday.

The crowd brings the number of foreign visitors to about 10 times more than the same period last year, a manager at a local travel agency told Xinhua.

About 500 visitors even rented a football pitch at a local college to better view the eclipse, said Cao Fushan, director of the provincial administration's general office.

As astronomy lovers around the world flood China for the solar eclipse, the National Meteorological Center Monday warned of rain and heavy cloud cover in the area where the total eclipse will be most visible.

Thundershowers or thick clouds may overcast many cities in the Yangtze River Valley, including Shanghai, Chongqing and Wuhan as well as the eight sites with the best views recommended by the National Astronomical Observatories, according to local weather stations.

National Astronomical Observatories have placed a number of live studios within the totality path. In the worst case, people can watch the scene via live coverage on TV or on the Internet.