IAU 1976天文常数系统中的基础常数

Primary Constants in IAU 1976 System of Astronomical Constants

对IAU1976天文常数系统中的基础常数的测定方法进行了评述。指出十个基础常数已发生了许多变化：光速已成为定义常数，地球赤道半径可用大地水准面的重力势代替，黄经总岁差需进行修改，章动常数已不能称为基础常数，其它常数也都有了新的测定结果。IAU1976天文常数系统已跟不上天文学的发展，并存在很大的缺陷，必须进行修订和改进。天文常数的测定方法和理论研究都在迅速发展之中，我们应当关心这个领域的研究。

A perfect system of astronomical constant has a very important significance for the comprehensive analysis of astronomical observational data and the mutual comparison of research result. In this paper, the determination method and the current best estimates of the primary constants in IAU 1976 System of Astronomical Constants are reviewed. It indicates that ten primary constants have changed a great deal. The speed of light becomes the defining constant;The earth equatorial radius may be replaced by the geopotential value of the geoid; The general precession in longitude needs to be revised; The nutational constant is unsuitable for the name of the primary constant; Other constats have also the new values. IAU 1976 System of Astronomical Constants falls behind the latest development in astronomy. Its improvement and modification must be made. The determination method and theoretical study for astronomical constant develop rapdily. We should concern ourselves with this field.