Total Lunar Eclipse: February 21, 2008

Geographic Region: central Pacific Ocean, Americas, Europe, Africa

The first lunar eclipse of 2008 is perfectly placed for observers throughout most of the Americas as well as western Europe. The eclipse occurs at the Moon's descending node, midway between perigee and apogee. During the eclipse, Saturn lies about 3° northeast of the Moon and shines brightly (mv = +0.2) because it is near opposition.

The Moon's orbital trajectory takes it through the southern half of Earth’s umbral shadow. Although the eclipse is not central, the total phase still lasts nearly 25 minutes. The timings of the major phases of the eclipse are listed below.

At the instant of greatest eclipse (03:26 UT) the Moon lies near the zenith for observers in French Guiana. At this time, the umbral magnitude peaks at 1.1062 as the Moon’s northern limb passes 7.2 arc-minutes south of the shadow’s central axis. In contrast, the Moon’s southern limb lies 3.3 arc-minutes from the southern edge of the umbra and 38.4 arc-minutes from the shadow centre. Thus, the northern half of the Moon will appear much darker than the southern half because it lies deeper in the shadow. Since the Moon samples a large range of umbral depths during totality, its appearance will change dramatically with time. It is not possible to predict the exact brightness distribution in the umbra, so observers are encouraged to estimate the Danjon value at different times during totality. Note that it may also be necessary to assign different Danjon values to different portions of the Moon (i.e., north vs. south).

During totality, the spring constellations are well placed for viewing so a number of bright stars can be used for magnitude comparisons. Regulus (mv = +1.40) is 3° northwest of the eclipsed Moon, while Procyon (mv = -0.05) is 40° to the west, Spica (mv = +0.98) is 51° to the southeast, and Arcturus (mv = -0.05) is 58° to the northeast. Alphard or Alpha Hya (mv = +1.99) is 23° to the southwest and Saturn (mv = +0.2) is just 3° to the northeast of the Moon.

The entire event is visible from South America and most of North America. Observers along North America's west coast miss the early stages of the partial eclipse because it begins before moon rise. Alaskans in Anchorage and Fairbanks experience moonrise during totality but bright evening twilight will make it difficult for sourdoughs to view the event. Western Europe and northwest Africa also see the entire eclipse. Further to the east (east Africa and central Asia), the Moon sets before the eclipse ends. None of the eclipse is visible from eastern Asia or Australia.

Eclipse map and predictions courtesy of Fred Espenak - NASA/Goddard Space Flight Center.
For more information on solar and lunar eclipses, see Fred Espenak's Eclipse Home Page:

http://sunearth.gsfc.nasa.gov/eclipse/eclipse.html