阳光透过鱼缸投射出4级彩虹的光路分析

Optical path analysis of four-order rainbows by the sunlight through the fish tank

利用几何光学研究了阳光透过矩形玻璃鱼缸在墙上以及天花板上产生4级彩虹现象的等效光路图,分析了彩虹级数与太阳高度角、鱼缸底面倾角、水深以及水面宽度之间的关系,解释了由全反射引起的缺级以及彩虹部分颜色缺失(先从紫色开始缺失)的现象.

The equivalent optical path diagram of the four-order rainbows phenomena on the indoor wall and ceiling by sunlight passing through a rectangular glass fish tank was studied by using the geometric optics method.The relationship between the orders of rainbow and the solar altitude angle,the inclination angle of the bottom of the fish tank,the water depth and the water surface width was analyzed.In addition,the missing orders caused by total reflection and the missing color of the rainbow(starting from purple)were also explained.