Analysis of the Effects of Errors on the fading of the Graduated Circle

A large reflect meridian circle is an instrument for the absolute determination of the declination and right ascension of a star. It is one of the prerequisites for the accurate determination of the deelination to study the graduated circle all-sidedly and carefully so as to improve the accuracy of the circle reading. On the basis of the summation of predecessors' determination of the errors of the circle division, we propose a "one-shot determination method" for fixing the angular distance of the reading microscope¹. The effects of the eccentricity error of the circle, the tilt of the circle and the reading microscopes and the flexure of the circle on the circle reading are further discussed in this paper. It is proved that the arbitrary distribution of microscopes by means of the method for fixing the angular distance will hot affect the final accuracy of the circle reading.