Determining the Absolute Parameters of the Meridian Circle by Observing the Prime Vertical (Ⅴ) The Effect of the Higher Power Terms of the Directional Errpr in the Determined Values of Latitude

In this paper, the effects of the higher power terms of the directional error of the instrument, the diurnal abberation and the atmospheric refraction on the obtained results are discussed in the process of the determination of the instantaneous latitude of an observation station by means of the prime vertical observation method. The results show that the effect of the higher power terms of the directional error of the instrument is comparatively great within the observable range of the zenith distance, and the correction for the results must be made. Usually, the effects of the diurnal abberation and the atmospheric refraction are smaller and may be negligible within the required accuracy.