Complete circular rainbows can be seen under the right conditions; in particular, when viewing the mists over Niagara Falls early or late in the day. Circular rainbows can sometimes be seen from an airplane when it flies over clouds, the rainbow actually encircling the airplane's shadow on the clouds. One way to think about the rainbow is that the mist or rain is like a projection screen, and the rainbow can only be seen where the projection screen is. When the projection screen is large enough, you see the entire circular rainbow. | Complete circular rainbows can be seen under the right conditions; in particular, when viewing the mists over Niagara Falls early or late in the day. Circular rainbows can sometimes be seen from an airplane when it flies over clouds, the rainbow actually encircling the airplane's shadow on the clouds. One way to think about the rainbow is that the mist or rain is like a projection screen, and the rainbow can only be seen where the projection screen is. When the projection screen is large enough, you see the entire circular rainbow. |