In 1977, archaeologists unearthed a great number of precious relics, including the unknown object, in the tomb of Xiahou Zao (the 2nd century BCE), the 2nd Marquis of Ruyin of the Western Han dynasty. However, no one has been able to identify the object as well as to explain the possible function of a pair of overlapping lacquered disks found in the same tomb.
A team of Yunli Shi, a professor at the Department of the History of Science and Scientific Archaeology, University of Science and Technology of China, has now proposed that the object is a special gnomon with template, while a pair of lacquered disks is an equatorial device for the positional observation of celestial bodies. Both are the oldest astronomical measuring instruments with definite information of date that can still be seen in the world. The findings appear in the Studies in the History of Natural Sciences. Read more.