Probable photographic detection of the natural seventh-order rainbow

摘要

We present a stacked and contrast-enhanced image comprised of 12 digital photographs that shows a series of color hues in the correct order and location to be part of the seventh-order rainbow. The observation was made on September 22, 2013, near Magdalena in New Mexico (USA). The seventh-order rainbow is located at 64 degrees from the Sun in a region of the sky with little interference from the zero-order glow. The color hues in the image range from red to blue-violet, spanning about 12 degrees in total extent; their locations generally agree with a numerical Debye-series simulation of the seventh-order rainbow. Despite the low color contrast of the seventh-order rainbow, the current observation indicates that it is feasible with current digital-imaging technology to detect this higher-order rainbow in near-ideal atmospheric conditions. (C) 2014 Optical Society of America