13 December 2007
A Ringed Star
A Sun halo gleams over the BA Conference Center.
Photo by Aymen Ibrahem, Senior Astronomy Specialist
On 29 November 2007, there were magnificent patterns of high clouds in the sky of Alexandria, Egypt. Observing from the BA Plaza, BA Senior Astronomy Specialist Aymen Ibrahem imaged a beautiful Sun halo that shone around the Sun during that day.
Sun halos, also known as icebows, are fascinating optical atmospheric phenomena that are similar to the rainbow. They shine as colorful arcs or circles around the Sun. While rainbows are associated with rains, icebows occur when high clouds, known as cirrus clouds, lie near the Sun. Icebows are formed due to the refraction of sunlight through tiny ice crystals contained in the cirrus clouds, not droplets of rain.
Sun halos are often 22 degrees in radius. As sunlight is dispersed into a spectrum in the crystals, Sun halos are usually red-tinged, but may show other colors of the spectrum, depending on conditions. There are also Moon halos, but they are fainter than Sun halos.
"The halo was nearly a complete circle," said Ibrahem. "This may happen only two or three times in Alexandria annually. The Sun was reminiscent of Saturn, the ringed wonderful planet." Ibrahem took numerous images of the rare celestial spectacle. He imaged the shining ring with the Planetarium and the BA Conference Center as foreground objects.
Picture Gallery
Fig (1)
Sun Halo over the Planetarium
Photo by Aymen Ibrahem, Senior Astronomy Specialist
Fig (2)
Sun Halo and Aircraft Contrail over the Planetarium
Photo by Aymen Ibrahem, Senior Astronomy Specialist
Further Reading
A Fading Star
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White Wagtails Return to Alexandria
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Aymen Mohamed Ibrahem
Senior Astronomy Specialist