meridian transit

基本解释

The low-latitude meridian circle is requested to determine the transit time and the apparent zenith distance simultaneously when a star is passing across the meridian of the instrument;
为了满足低纬子午环绝对测定方法的要求，即在子午方向同时测定天体中天时刻和天顶距；
The first meridian circle of China has been installed at CSAO in April 1990. This horizontal reflecting transit circle with 240ram effective aperture is developed by CSAO, NAIF and CUO.
我国第一架水平子午环，其有效口径在世界上为最大，于1990年4月在陕西天文台临时观测室安装就绪。