Small telescopes see a lot of sky but can detect only strong signals. Large ones, which can detect weak signals, have a narrow focus.

大型的望远镜虽可以检测到微弱的信号，却只有很小的焦距。

youdao

Small telescopes see a lot of sky but can detect only strong signals. Large ones, which can detect weak signals, have a narrow focus.

大型的望远镜虽可以检测到微弱的信号，却只有很小的焦距。

youdao