22 May 2007
Photo by Aymen Ibrahem, Senior Astronomy Specialist
On Tuesday, 22 May 2007, the Moon occulted Saturn, the ringed, wonderful planet.
This rare celestial event was visible in Europe and regions in the Middle East. Cairo and Alexandria were among the most favourable observing sites.
The Moon was moving at a speed of about 3,500 km/hr, a speed nearly equal to that of the supersonic Concorde airliner.
To an Earth-based observer, however, the apparent lunar motion was quite slow, due to the relatively large distance of the Moon of about 400,000 km.
The sky was clear enough for the phenomenon to be easily observed, but a thin layer of mist created the fascinating optical effect of "lunar corona".
Corona is Latin for crown. When moonlight passes through thin clouds or mist, glowing rings of hues of red and blue are formed around the Moon.
At about 11:10 p.m., Saturn disappeared behind the lunar disk.
This was one of the most splendid cosmic views I have ever observed.
Saturn reappeared shortly before moonset.
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