APOD 2.5

Anticrepuscular Rays Over Colorado

Although this looks like its something supernatural, this scene is created by nothing more than the setting sun and a few clouds. These are anticrepuscular rays! To understand them you should first try to envision common crepuscular waves which you see anytime sunlight pours through scattered clouds. The projections of these line onto the sphereical sky are great circles. At the anti-solar point 180 degrees from the Sun, they are referred to as anticrepuscular rays.