Lunar Eclipse over the Bibliotheca Alexandrina
The photo shows the partial lunar eclipse of 16 August 2008.
Photo by Aymen Ibrahem, Senior Astronomy Specialist

On the evening of Thursday, 31 December 2009, a partial lunar eclipse will be visible in the skies of Egypt. Lunar eclipses are among the most beautiful natural phenomena. They occur when the Moon passes through Earth’s shadow. Thursday’s lunar eclipse will begin at 19:17 EET, and will last over four hours. This eclipse is of small magnitude, as only a small portion of the Moon will be darkened, at maximum eclipse.

Earth’s shadow extends for over a million km in space. It consists of two portions: a dark inner part, termed the umbra, and an external pale part, termed the penumbra. The Moon will enter the penumbra at 19:17 EET. This phase of the eclipse is termed the penumbral eclipse. During a penumbral eclipse, the illumination of the Moon is only slightly affected. However, when the Moon passes through the northern rim of the umbra, at 20:52 EET, the partial eclipse will begin. It will end at 21:52 EET. Intriguingly, only a small portion of the southern lunar limb will appear to be missing, during the partial eclipse. The eclipse ends when the Moon exits the penumbra, at about 11:28 EET.

During total lunar eclipses, the Moon plunges into the umbra, and becomes totally covered by the umbra. Total lunar eclipses are spectacular events, particularly when viewed through a small telescope, or binoculars, as the totally eclipsed Moon often glows in fascinating hues of red, yellow, and orange, due to sunlight, filtered through Earth’s atmosphere.

Unlike solar eclipses, lunar eclipses can be viewed safely with the unaided unprotected eye, or through the telescope. Observing the Sun with the eye severely damages the eye. Never look directly at the Sun with your eyes, or through the telescope, or any other optical aid. The Sun can be observed only through special optical equipment. Observe the Sun only under the supervision of astronomy specialists.

Further Reading

http://eclipse.gsfc.nasa.gov/LEplot/LEplot2001/LE2009Dec31P.pdf

Aymen Mohamed Ibrahem

Senior Astronomy Specialist