Contrails in Moonlight
25 May 2007




Contrail in Moonlight

Photo by Aymen Ibrahem, Senior Astronomy Specialist

On 3 April 2007, weather in Alexandria permitted the formation of aircraft contrails. The Moon was shining in the gibbous phase, only one day past Full Moon. Mr. Aymen Ibrahem, Senior Astronomy Specialist, took interesting photos of contrails, glowing in moonlight, from Bibliotheca Alexandrina Plaza.

Aircraft contrails are trails of tiny ice crystals, formed in the upper air due to the exhaust of aircraft engines. They may be also described as artificial cirrus clouds, scince they are similar to this type of high-altitude clouds. As they are composed of water, aircraft contrails are not regarded as air pollution.

Ibrahem routinely observes aircraft contrails, as part of his studies of weather and optical atmospheric phenomena. He produced numerous images, showing the variation of color of contrails during sunset, sunrise and twilight. He also recorded the beautiful phenomenon of contrail irisation, which is observable when a contrail is formed very near to the Sun or the Moon in the sky.

While carrying out the nighttime observation of the contrails, Ibrahem spotted a garden snail that was crawling amid the plants of the Library. He took several images of this fascinating nocturnal animal, which soon retracted, probably due to the repeated flashes of Ibrahem's camera!

Further Reading

Calm after the Storm

Aymen Mohamed Ibrahem

Senior Astronomy Specialist

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