Experiments of the Differential Image Motion Method for Measureing the Seeing

In this paper, the physical meaning of the Fried's parameter r₀(i.e.the atmospheric coherent length)and the reason why this parameter is chosen to discribe the atmospheric seeing are firstiy explained, and then, an excellent method for measuring r₀, i.e. the differential image motion method, is introduced.The six characteristics of this method are summarized and the tested results and the experiment parameters for measuring the seeing twice by means of this method at the Yunnan Observatory are given.Finally, the results are analysed and discussed.