Principle and design of a ringsight consisting of calcite crystal plate and polarized elements are proposed.
本文介绍一种光环瞄准镜的原理和设计，它是用方解石晶体薄片和偏振器件组成。
2
The ringsight presents a set of concentric rings when it is illuminated by the target and the background. Brightness of the rings is in proportion to that of the target and the background.
在目标光和背景光的照射下，呈现出一组同心圆环，其亮度与目标和背景的亮度成正比。
3
But, for answer, the old man only held his lanthorn up, so that in the ring of its pale light they saw some sight or other in the street.