It is nearly clear image of rainbow that is formed after a rain.It is consider as result of refraction of sunlight by water droplets.
<a href="//commons.wikimedia.org/w/index.php?title=User:Muhammad_59&amp;action=edit&amp;redlink=1" class="new" title="User:Muhammad 59 (page does not exist)">Muhammad 59</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>