This lunar calendar, found in Dunhuang Grottos, northwest China 's Gansu province, precisely predicted the dates of eclipses on February 16 and August 16 in 451 BC, though the exact times were not given, scientists said.

Experts with the Dunhuang Research Institute ruled out the possibility that the "forecasts" were recorded after the eclipses had occurred.

Since the eclipses happened at noon on February 16 and around midnight or 2 am on August 16 in 451 BC, the eclipse at noon could not be observed by the naked eye, or recorded in common calendars, according to experts.

Furthermore, documental experts noted, the calendar's handwriting was constant and the forms looked very consistent, which would exclude the possibility of post-elipse revision.

According to historians and documental experts, ancient lunar calendars were compiled one year in advance and this calendar is the earliest ever found in the world-renowned Dunhuang Grottos and the only one found during the Northern Dynasties (386 BC-550 BC).

(People's Daily June 27, 2002)