“云南第一天文点”与清康熙年间的全国大地测量

The First Astronomical Point in Yunnan

在昆明市区的云南大学校园内,有"云南第一天文点"的确切点位可寻,它是指1934年用天文观测方法得出昆明的经纬度坐标,是对清康熙年间始测的数据进行复测,目的是得到昆明市区更精确的经纬度。康熙时在昆明始测是用经纬仪,称为大地测量,它仅是该次开展全国大规模大地测量中的一个点,也是那时在云南使用经纬仪测量的29个点之一。其他还有若干个点是由若干人用三角法测量推算后,填充在29个点之间,才绘制成云南地图。在云南的始测时间是在康熙五十三年至五十四年(1714~1715)。始测昆明点是1714年,由费隐和潘如二人主持,或是在1715年,主持人是雷孝思。始测为后来的复测铺了路,并提供了比较的依据,其本身具有重要的实践价值。这次测量就全国而言,先前丈量尺度长短不一致得到了统一。另外,让世人了解昆明乃至云南所处的地理位置,有了明确具体的数字概念。

In the campus of Yunnan University, the down town area of Kunming, one can find a certain ＂first astronomical point in Yunnan＂ which is the longitude and latitude coordinates of Kunming measured by the astronomical observation method in 1934, and it was re-measured for an original data during the Kangxi of the Qing Dynasty and the purpose of the re-measurement is to obtain more accurate coordinates for Kunming. The original measurement during the Kangxi time was using a transit instrument, also called the geodesy, and in the geodesy surveying for whole China during 1714-1715 29 points were measured in Yunnan. The first result was the basis of the re-measuring and offered the data which could be compared with the data remeasured later, and the first measurement itself has an important practical value. This measurement unified the different rules used before. In addition, it could make people to know the geographical location and to have a certain numerical idea for Kunming, even Yunnan.