天球参考架零点的测定（Ⅰ）－观测对象和观测方法的分析

Determination of Zero Point for the Celestial Reference Frame(I) -Analysis of Objects Observed and the Observational Method

本文叙述了测定天球参考架零点位置的意义和途径，通过比较，认为小行星是最合适的观测对象，并且在分析了过去用小行星观测测定天球参考架零点位置的误差较大的原因后，提出了用低纬子午环高精度地测定小行星瞬时位置的观测方法。

The importance Of determination of the zero point for the fundamental reference frame and the observational method used are described in this paper. The Newcom's method used the motions of inner planets to derive the equinox and equator,however the observations in the day time are usually subject to sources of systematic and random errors,which are four times to ones in the night observation. For the object that has the apparent area,the irregularity of the surface edge causes the error of its position. By comparison,the minnor planet is considered as most appropriate object. However in the past due to the observation error,the zero points determined by observing the minnor planets had large difference. we anaylze the reason and propose a new mothed in which we will use the low latitude merdian circle to determine the positions of asteriods. It is shown that the accuracy of the position will be reached to±0. '03.