BEIJING - A new web portal dedicated to protecting astronomical heritage sites has been launched during the 28th General Assembly of the International Astronomical Union (IAU).

The site, at www.astronomicalheritage.net, is the latest achievement in the collaborative work between IAU and UNESCO (United Nations Educational, Scientific and Cultural Organization), according to Clive Ruggles, chair of the IAU's Astronomy and World Heritage Working Group. Collaboration between IAU and UNESCO started four years ago,

The site will work as a publicly accessible database, discussion forum and document repository on astronomical heritage sites throughout the world, said Ruggles, emeritus professor of archaeoastronomy with the University of Leicester, in Britain.

"Approximately, 40 sites have been included in the site," Ruggles said, "some are already on the UNESCO's World Heritage List, not usually for their astronomical significance, some are on national tentative lists and some are not at all on any list. It's a mixture."

He said that "a lot of valuable astronomical heritages haven't been recognized".

Up until three years ago, there was only one site that was inscribed on the World Heritage List for its astronomical associations. Called Struve Geodetic Arc, it starts in Norway and extends through 10 countries down to the Black Sea.

"It is a survey network set up in the 19th century trying to measure the shape of the earth," Ruggles said, "so it's not a predominantly astronomical site, but involves the use of astronomy for geodesy."

There are other astronomical heritage sites on the list, but not inscribed because of their value in astronomy, such as the Greenwich observatory in Britain.

In the last two years, there have been two sites inscribed on the World Heritage List explicitly for their astronomical significance. One is the Jantar Mantar observatory in India and the other is Dengfeng observatory in China's Henan province.

"Our portal is both for the public and professionals. We want to make people more aware of the importance of these heritages. We also want to help professionals better understand the criteria of the judgement if they want to put a site forward to the World Heritage List," he said.

Currently, three Chinese sites, including Dengfeng observatory, Taosi observatory in Shanxi province and Beijing ancient observatory, have been included in the portal.

The portal will not only feature sites and monuments, but also other types of astronomical heritage such as portable instruments, intangible cultural practices as well as dark-sky places.

"A lot of our most precious astronomical heritage - both ancient and modern - is under threat. If we don't act to try to protect and preserve it, we run the risk of losing it." Ruggles said.