Since the invention by the Han-dynasty astronomer Zhang Heng (78-139 AD) of the world 's first water-driven armillary sphere, most Chinese astronomical instruments were fitted with automatic drive mechanisms. But sadly, detailed descriptions of them have not survived--only brief mentions in astronomical annals from various periods. As for star charts, most from before the Song dynasty have also been lost.
中國自張衡以來，天文儀器多裝有自動化機械，可惜沒有留下記錄，只在歷代天文志裡簡單記載；至於星圖，宋以前的也多遺失不存。