Determining the Absolute Parameters of the Meridian Circle by Observing the Prime Vertical(Ⅳ) Further Discussion of the Applicable Ranges of the Observing Method

The main sources of error of the principle of the absolute determination of azimuths and equatorial point on the graduated circle of a meridian circle proposed in Documents 1 and 2,and its applicability to geographic latitudes are further studied in this paper.We come to the conclusion that the method is not only applicable to the lower latitudes except the areas,nearby the equator,but also to middle and higher latitudes,that is to say,this method can be used to determine the position of a star absolutely,with the result having higher accuracy,within the range of the latitudes where all the existing observatories in the world are located except for a zone of φ=±50.