From Laboratory Equipment magazine on-line
Maybe I should have posted this in the Astromonical Equipment forum.In 1977, archaeologists unearthed a great number of precious relics from the tomb of Xiahou Zao (?-165BCE), the 2nd Marquis of Ruyin of the Western Han dynasty. They named a piece of lacquerware "lacquerware of unknown name", for no one has been able to identify it. Divergent views also have been held over the possible function of a pair of overlapping lacquered disks from the same tomb.
After more than two years cooperative study with experts from the Anhui Museum and the Fuyang Municipal Museum, Shi Yunli, professor from the Department of the History of Science and Scientific Archaeology, Univ. of Science and Technology of China, has recently resolved the puzzles and found that the former is a special gnomon with template, while the latter parts of a 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 were published in the Studies in the History of Natural Sciences, the leading Chinese journal in the history of science.
The gnomon with template is a typical instrument used by ancient Chinese astronomer in determining the advent of different seasons with the gnomon shadows cast on the template by the midday sun. It consists of a vertical pole and a level template laid in south-north direction at the foot of the pole. The gnomon with template from the tomb of Xiahou Zao has two symmetric and foldable parts. As being fully set up in the south-north direction, the midday sun will cast the shadow of a vertical tablet in the northern half onto three fixed positions on the template respectively on the days of the Summer Solstice, the Vernal/Autumnal Equinoxes, and the Winter Solstice.
I was a little unclear if the object pictured in the article is the actual historic piece (in which case it is in great condition or been restored) or a reproduction made from the original.