primary mirror

• 主镜

primary mirror的用法和样例：

例句

1. With your eye close to the focuser, you can see the primary mirror reflected in the secondary, and the secondary and its spider in turn reflected in the primary.
   把眼睛靠近调焦座，你会看见副镜中有主镜的反射像，而副镜和它的支架也在主镜中有反射像。