Canon 50D | ISO 100 | f11 | 76.0 | 10mm

Another Christmas Day shot from 2009.

After the <a href="http://www.flickr.com/photos/aramisfirefly/4266... rainbow</a> and <a href="http://www.flickr.com/photos/aramisfirefly/4223... long exposure clouds</a>, I saw something pretty special.

This lightrays are coming back from the sunrise sky, on sunset.

They are called Anticrepuscular rays.

I was shooting ND400 at the time and swung around and saw this amazing feat. I do regret not getting an non-ND400 shot, doh, but the the people on the people in motion look look eh?

<b>About Anticrepusular Rays</b>

Anticrepuscular rays are similar to crepuscular rays, but seen opposite the sun in the sky. Sunlight travels in straight lines, but the projections of these lines on Earth’s spherical atmosphere are great circles. Hence, straight-line crepuscular rays from a setting (or rising) sun can appear to re-converge at the antisolar point. Anticrepuscular rays are most frequently visible near sunrise or sunset. Crepuscular rays are usually much brighter than anticrepuscular rays. This is because for crepuscular rays, seen on the same side of the sky as the sun, the atmospheric light scattering and making them visible is taking place at small angles (see Mie theory).

Although anticrepuscular rays appear to converge onto a point opposite the sun, the convergence is actually an illusion. The rays are in fact parallel, and the apparent convergence is to the vanishing point at infinity.