This is an excellent figure, not that far from diffraction limited. 这是一个极不错的数字,还没有到衍射的极限。
This optic is diffraction limited at the center field but not at the edge. 衍射极限只在中心部分起了作用而不是边缘。
The obvious question becomes : is this diffraction limited or not? 现在问题变成:这个是不是衍射极限的作用?
When we use the term diffraction limited, we must also qualify where in the telescope field of view this is happening. 当我们使用衍射极限这个概念时,我们必须限定是在望远镜的哪一个部分。
So how much surface deviation can we tolerate before our optic is no longer diffraction limited? 那么多大的镜面误差是是我们能够容忍的呢?