Rainbows and Shadows

Occasionally the sunlight falling on the rain is partially obscured, with the clouds casting long shadows.

Broken rainbow Wedge of rainbow

The varying illumination gives the illusion of an irregular bow. In this example a fragment of secondary bow is also visible.

A shaft of sunlight creates this wedge of rainbow at the edge of a heavy Welsh shower. With more sunlight falling on the lower section it appears thicker.

Rainbow shadows converge Rainbow spokes

The effect doesn't last very long as the moving clouds change position, this one lasted a couple of minutes. Because the drops inside the bow are also strongly reflecting sunlight the shadows are quite obvious. These converge on the centre of the bow at the antisolar point.

Here the falling rain is fairly even so the shadows dominate. Although it is just perspective that causes the shadows to converge it creates the illusion that the shadows are radial spokes within the rainbow.

Weak anti-crepuscular rays in a late afternoon shower.

Other Bows Topics