beam compasses

例句：

1. 1. The beam compasses are used to align the laser beam accurately.
   光束指南针用于准确地对齐激光束。
2. 2.The engineer used a beam compasses to measure the angle of the building.
   工程师使用光束指南针来测量建筑物的角度。
3. 3.The beam compasses helped the astronaut find his way back to the launch pad.
   光束指南针帮助宇航员找到返回发射台的路。