-
-
- 蚀天体的部分或全部受到其他天体的遮掩而变得晦暗，这种现象与特定观测者相关
The partial or complete obscuring, relative to a designated observer, of one celestial body by another.
- 天底天球上，在观测者垂直向下的一点，与天顶完全相对
A point on the celestial sphere directly below the observer, diametrically opposite the zenith.
- 旋标装置飞机控制板上的指示器或观测仪，用来测量角度
An indicator or a sighting apparatus on a plane table, used in angular measurement.
-
-
