02 March 2007

total lunar eclipse saturday 03 march 2007

previous eclipse photo: courtesy www.marranomusic.com
nasa imagery
The first of two total lunar eclipses in 2007 is unique in that it is partly visible from every continent around the world. The eclipse occurs at the descending node, 3.2 days before apogee and 1.9 days after the Moon occults Saturn (northern and eastern Europe). During the eclipse, the Moon is in southern Leo, about 13º east of the 1.3-magnitude star Regulus (alpha Leo). The Moon's orbital trajectory takes it through the northern half of Earth's umbral shadow. Although the eclipse is not central, the total phase still lasts 73 minutes. The timings of the major phases of the eclipse are listed below.

Penumbral Eclipse Begins: 20:18:11 UT
Partial Eclipse Begins: 21:30:22 UT
Total Eclipse Begins: 22:44:13 UT
Greatest Eclipse: 23:20:56 UT
Total Eclipse Ends: 23:57:37 UT
Partial Eclipse Ends: 01:11:28 UT
Penumbral Eclipse Ends: 02:23:44 UT

The Moon's path through Earth's shadows as well as a map illustrating worldwide visibility of the event are shown in Figure 1.

At the instant of greatest eclipse (23:21 UT) the Moon will lie in the zenith for observers in Nigeria and Cameroon. At this time, the umbral magnitude peaks at 1.2331 as the Moon's southern limb passes 2.4 arc-minutes north of the shadow's central axis. In contrast, the Moon's northern limb will lie 6.9 arc-minutes from the northern edge of the umbra and 32.2 arc-minutes from the shadow centre. Thus the northern sections of the Moon will appear much brighter than the southern part, which 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 (see Danjon Scale of Lunar Eclipse Brightness). 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 will be well placed for viewing so a number of bright stars can be used for magnitude comparisons. Spica (mv = +0.98) is 40º southeast of the eclipsed Moon, while Arcturus (mv = -0.05) is 49º to the northeast. Alphard or Alpha Hya (mv = +1.99) is 28º to the southwest and Procyon (mv = -0.05) is 50º to the west. Saturn shines at magnitude +0.8 about 24º northwest of the Moon near the western border of Leo.

The entire event will be visible from Europe, Africa and western Asia. In eastern Asia, moonset occurs during various stages of the eclipse. For example, the Moon sets while in total eclipse from central China and southeast Asia. Western Australia catches part of the initial partial phases but the Moon sets before totality. Observers in eastern North and South America will find the Moon already partially or totality eclipsed at moonrise. From western North America, only the final penumbral phases are visible.

Table 1 lists predicted umbral immersion and emersion times for 20 well-defined lunar craters. The timing of craters is useful in determining the atmospheric enlargement of Earth's shadow (see Crater Timings During Lunar Eclipses).
see also
kalb weather blog
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