Red Rainbow Over Syracuse, Italy

January 23, 2019

Red Rainbow_Arcobaleno Sopra Siracusa (3)

Photographer: Dario Giannobile
Summary Authors: Dario Giannobile; Jim Foster

Red rainbows occur during twilight when the Sun is just below the horizon. In this case, sunrise is still several minutes away. If the Sun hugs the horizon or lies just beneath it, the violet, blue, green and yellow colors are attenuated by the long path length of sunlight though our atmosphere. Note that path length is at a minimum when the Sun is directly overhead. Red rainbows produce the highest arcs in the sky -- approximately 43 degrees above the horizon or nearly half the way to the zenith. If you look closely, a faint secondary bow, the result of a double reflection of the rays of sunlight inside the raindrops, can be seen. Photo taken on December 1, 2018.

Photo Details: Camera: Canon EOS 6D; Software: Adobe Photoshop CC 2018 (Windows); Exposure Time: 0.040s (1/25); Aperture: ƒ/5.6; ISO equivalent: 200; Focal Length: 15.0mm; Lens: EF8-15mm f/4L FISHEYE USM.