zenith h distance天顶距
computed zenith distance计算顶距
circummeridian zenith distance近子午圈天顶距
reciprocal zenith distance双向天顶距
observed zenith distance观测顶距
true zenith distance真顶距;真天顶距;实际天顶距;真值
apparent zenith distance[天] 视天顶距;视天顶距
calculated zenith distance计算顶距
double zenith distance双天顶距