APOD 2.4

 

This spectacular image was taken in Boulder, Colorado.  This APOD post intrigued me not only because I am applying to University of Colorado at Boulder, but also because this spotlight appearance of the sky actually occurred naturally.  The effect is created by the setting Sun's light projected onto the clouds, which are scientifically referred to as anticrepuscular rays.  Anticrepuscular rays converge in the opposite direction from the Sun, which is called the antisolar point or the point in the celestial sphere directly across from the Sun.  This effect is essentially an optical illusion based on perspective, similar to the converging lines of a long, straight road that appear to meet at one point,  These sun rays are actually parallel, but appear to converge at our horizon.  Without clouds blocking them, anticrepuscular or crepuscular rays, which have the opposite effects and converge onto the Sun, they can be easily spotted and are not rare but must be sighted at the right time.