The Young Sky Watchers and the Rainbow
A bright rainbow shines over the BA. Three children, visible at the left corner of the image, are observing the rainbow. The foreground objects are the BA Planetarium and statue of Prometheus.
Photo by Aymen Ibrahem, Senior Astronomy Specialist

On the evening of 7 February 2008, there was a light shower in Alexandria, Egypt. Observing from the BA Plaza, BA Senior Astronomy Specialist, Aymen Ibrahem, imaged a spectacular rainbow during the rain.

“The rain was light, and the Sun was shining in a partly cloudy sky,” said Ibrahem. “A fascinating rainbow arched high, opposite to the Sun, in the northeastern sky. With a great thrill I began photographing the celestial spectacle. Bright rainbows are rare. Three kids were near me. They rejoiced when they noticed the rainbow, and observed it for a while.”

A rainbow is formed due to refraction and reflection of sunlight within the rain droplets. Double reflection of sunlight within the droplets produces a larger secondary rainbow, outside the primary rainbow. The secondary rainbow is much fainter than the primary. It is also a rare phenomenon.

In the primary rainbow, red is the outermost color, while violet is the innermost. Interestingly, the order of colors is reversed in the secondary rainbow. Both the primary and secondary rainbows are centered on the antisolar point, the point opposite to the Sun in the sky.
The rainbow lasted about six minutes, from 16:43 EET (14:43 GMT),to 16:49 EET. Ibrahem took interesting images of the rainbow, with the Library and Planetarium as foreground objects. Some of his images are presented in the picture gallery below.

Picture Gallery

Fig (1)
Double Rainbow
The picture shows two rainbows over the BA Planetarium. The brighter rainbow is known as the primary rainbow, while the fainter rainbow, visible as a faint arc outside the primary, is termed the secondary rainbow.

Fig (2)
This is a contrast-enhanced copy of Fig (1), revealing the primary and secondary rainbows.
Image processing by Aymen Ibrahem, BA Senior Astronomy Specialist

Fig (3)
Rainbow and Seagull
The picture shows a seagull near the upper end of the rainbow.
Photo by Aymen Ibrahem, BA Senior Astronomy Specialist

Fig (4)
The brightness of the rainbow has much decreased.
Photo by Aymen Ibrahem, BA Senior Astronomy Specialist

References

Atmospheric Optics (a famous website by Les Cowley)
Hyper Physics (a website presented by the Department of Physics and Astronomy, Georgia State University)

Aymen Mohamed Ibrahem
Senior Astronomy Specialist