Anti-Crepuscular Rays at Sunset

Donald F. Collins
Warren Wilson College

This image was photographed soon after sunset on Dec. 31, 2003 looking away from the sun at 5:39 pm from the author's home near Asheville, NC. The sky was extremely clear all day. The dark rays are shadows caused by mountain peaks or clouds in the distance behind the camera. The shadows are parallel, but they appear to converge just above the “Four Brothers” mountain in the foreground. The convergence of the parallel rays is analogous to the convergence of parallel railroad tracks in the distance. Extensive image processing was performed to enhance the contrast of the shadows.

The image at right is the sun rising on the summer solstice (June 21, 2002) photographed from the same location. Notice that the sun rises from the second knob from the left of the “Four Brothers” mountain. This is the same location at which the sunset shadows in the top picture converge. The sunset shadows was photographed very close to the winter solstice. The winter solstice sunset is diametrically opposite the summer solstice sunrise.

Below is another photograph of "anti-crepuscular" rays.  This was photographed soon after sunrise on Jan. 12, 2004 looking west with the sun having just risen in the southeast behind the camera.  The shadows in the sky are produced by clouds to the left of the photo.

Keep posted for more atmospheric and astronomical phenomena.