concave primary mirror
/kɒŋkˈeɪv ˈpɹaɪməɹi ˈmɪɹə/
n
English · concave primary mirror中文 · 凹面主镜Español · espejo cóncavo primarioFrançais · miroir primaire concave
意味：Mirror that collects light and whose shape makes it possible to direct it toward the secondary mirror.