CHINA'S new breed of archeo-astronomers studies the heavens as well as prehistory on Earth, notably a 4,100-year-old observatory where late Neolithic star-gazers accurately charted the seasons for legendary Emperor Yao. Yu Fei observes.

Just before dawn in a quiet village in north China, a short, middle-aged man hurries with a bundle of poles toward a clump of weeds to wait for sunrise.

The man busily measures and takes photos. He wants to prove that ancient astronomers were standing at the exact same place 4,100 years ago to determine the changing of seasons by observing the sunrise and discerning the best times for sowing or harvesting.

A researcher with the Institute of Archeology under the Chinese Academy of Social Sciences (CASS), He Nu is head of the excavation team at Taosi relic site in Xiangfen County, north China's Shanxi Province.

Unlike his Chinese archeological forebears, who carried their bedclothes, shovels and brushes to excavation sites, 46-year-old He is equipped with a four-wheel-drive vehicle, laptop computer, digital camera and mobile phone.

Influenced by modern Western archeology ideas, He sees and thinks farther and wider, to find a relevance to today in the remains of the past. Raising his eyes from the ruins below the weeds to the sun, He discovered what is believed to be the world's oldest observatory.

Chinese archeologists launched a project in 2001 to seek the origins of their 5,000-year-old civilization. Taosi is one of the most important sites in this project. Much evidence has been found to indicate the Taosi site might have been the capital of the legendary Yao and Shun period dating back more than 4,100 years.

In Chinese mythology, Yao and Shun were two sage emperors living on the middle reaches of the Yellow River. Many Confucian histories praised the two rulers as models of morality and benevolence, but skeptics in the early 20th century challenged their existence.

"If you want to know where China is going, you have to know where China came from. The excavation at Taosi will tell us where China came from, and whether Yao and Shun really existed," says He.

In his search for evidence of the lost, undocumented era at Taosi, He found the ruins of a mysterious semicircular building in 2003. He thought it important and excavated. He found indications that 13 stone pillars were originally erected at the site, with 12 gaps or intervals between them.

"It reminded me of Stonehenge in Britain. Ancient Chinese believed the sky was round, and all buildings related to the sky were built in the shape of circles. So we suspected the site might be related to astronomical observation," He says.

If it proved to be an observatory, it would be of great importance. The Confucian history, "Shangshu," says the first official act of Emperor Yao was to observe the sky and improve the calendar.

In those ancient times, life revolved around agriculture. A tribal leader with an accurate astronomical calendar could reliably direct agricultural production, and the tribe would thrive, giving the leader supreme power.

Could the Emperor Yao have once stood in that place to observe the heavens?

He and his colleagues have attempted to recreate ancient observation techniques at the site since 2003. He plants the poles where the stone columns once stood and watches the gaps. If he can see the sunrise above the hills through the gaps according to the seasonal divisions of the traditional Chinese calendar, he will prove his theory that this place was an observatory.

His observations from December 2003 to April 2004 seemed to be going well, but when he took them to astronomers, they pointed out that he had wrongly used three observation points. They said there must be only one.

"The distance between the three points is less than 30 centimeters. And our observations on the days of the winter solstice (around December 22), "major cold" (around January 20, indicating the coldest time of the year) and "grain rain" (around April 20, a time of increased rainfall which is good for crops) were very accurate. And the observation on the spring equinox (around March 20) was only one day later. How could that be wrong?" He argued with the astronomers.

"But I gave up, because I thought the astronomers were reasonable. I should respect science. That invalidated half a year's work. I was so distressed."

Many archeologists also questioned He's theory.

But He persisted and eventually found a new observation point. Further digging revealed traces of what is believed to be the original observation point 4,100 years ago: a rammed earth base 25cm in diameter, with its center just 4cm from the new point used by He.

The discovery of the original point and more than 70 rounds of observations provided evidence for He's theory, which won recognition in archaeological and astronomical circles.

Scientists from the National Astronomical Observatories and the Institute for the History of Natural Science under the Chinese Academy of Sciences showed great interest in He's study, and jointly started further research this year to find out whether the ancient observatory had other astronomical functions.

He's discovery has also roused interest in archeo-astronomy, a little understood field in China. He believes Chinese ancients were very advanced in astronomy, and other relics related to astronomy have probably been neglected.

"My theory about the astronomical function of the site was like a fantasy at the beginning. But you cannot bring forth new ideas unless you think wide," He says. "I'm often tortured by getting nothing. I feel like I'm trekking through sand with no end. When I'm exhausted, I suddenly find some shells of rare beauty. All the toil, tiredness and monotony are rewarded."

China's archeology was isolated from Western influences after the founding of New China in 1949. Like other sciences, archeological study in the former Soviet Union became the model for China. Unfamiliar with the Western theories, previous generations of Chinese archeologists walked a road of their own, and focused on verifying recorded history.

Archeology ground to a halt during the "cultural revolution" (1966-76). However, it has blossomed since because the government regards its discoveries as an important window on China's cultural development.

He was born in Beijing, where the ancient temples and pagodas fascinated him in his childhood. It was a time of great discoveries, such as the terra-cotta warriors and horses, which were found in 1974 near Xi'an in Shaanxi Province.

He studied archeology at Peking University and gained a master's degree in the Xia, Shang and Zhou dynasties, China's Bronze Age. He then gave up the opportunity to work in Beijing and went to work in the Jingzhou Museum in central China's Hubei Province, because he wanted to go to the frontier of archeological excavation.

Life at an archeological site is rough: Good food is scarce and He maybe gets to bathe in the town once a week. There are no weekends or holidays during the excavation seasons, and rest is taken when it rains. He recalls one period of no rain for more than 40 days.

Most of the time, He's work is monotonous: digging, clearing and drawing diagrams. The work in the storeroom is even more exacting. He sometimes has to piece together thousands of broken pottery pieces. The success rate is low.

Since the 1980s, Chinese archeologists have often had to rush to construction sites to search for the remains of ancient civilizations before the bulldozers destroy them.

They also have to race against tomb robbers. Hubei Province is home to many tombs of the Chu Kingdom of the Warring States Period (403-221 BC), but looters have plundered an estimated 90 percent of them.

"I don't like this kind of excavation. It distresses me to see those precious antiquities being unearthed, but we don't have any good method to preserve them. Many lacquer ware items and silks are destroyed," says He. "Later generations will appreciate the bounty of cultural relics found in our time, but they will also criticize us for being unable to protect them well."

The new generation of archeologists like He tries to keep up with trends in international archeological circles.

He attended the Department of Anthropology of San Francisco State University as a visiting scholar from 1995 to 1996, studying carved symbols with American scholars and participating in an excavation at a small Native American relic site.

"I benefited a lot from the year in the United States. Archeology is no longer restricted to archeologists in the United States. People from other fields, such as doctors or computer experts, also participate in the research. They are more open-minded, and are always willing to try something new, and bring vitality to the development of archeology. But China still lacks this kind of innovation," He says.

He believes archeological research should serve the social reality. "We should find objective laws formed over thousands of years, and the objective laws will direct our social development in the future."