Frederic E. Church's painting Rainy Season in the Tropics gives a good rendition of the double rainbow with Alexander's dark band well portrayed. This is the antisolar point and will be the centre of any rainbow. If the sun is high, the rainbow will be closer to the horizon. If it is too high, a rainbow may not be visible at all unless you have a high vantage point such as a mountain top or aircraft. They are most often seen around sunrise or sunset, but may be seen at other times.
Dark rays form when clouds cast their shadows on the surrounding air.
Although the suns rays are actually parallel, crepuscular rays appear to converge on the sun. This is the same perspective image we see when railroad tracks appear to meet at a single point in the far distance. Since thunder is caused by the rapid heating of the air during the passage of a lightning stroke, the path of thunder always follows that of the lightning. If lightning strikes very far away or vertically close to the observer, the times required for the sound to reach our ears from the extreme ends of the lightning path are similar, and the thunder sounds as if it comes from one area of the sky. However, if the bolt crosses the sky from side to side, or perhaps has a path that looks to us like an inverted letter L , the thunder reaches our ears from points along the path at distinctly different times.