Lunar Eclipse Timelapse
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10 سال پیش
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http://eclipse.gsfc.nasa.gov/OH/OHfig...
The first eclipse of the year is well placed for observers throughout the Western Hemisphere. The eclipse occurs at the lunar orbit's ascending node in Virgo. The apparent diameter of the Moon is close to its average since the eclipse occurs nearly midway between apogee (April 08 at 14:53 UT) and perigee (April 23 at 00:28 UT). This is the first of four consecutive total lunar eclipses in 2014 and 2015 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 78 minutes. The Moon's path through Earth's shadows as well as a map illustrating worldwide visibility of the event are shown in Figure 1. The times of the major eclipse phases are listed below.
Penumbral Eclipse Begins: 04:53:37 UT
Partial Eclipse Begins: 05:58:19 UT
Total Eclipse Begins: 07:06:47 UT
Greatest Eclipse: 07:45:40 UT
Total Eclipse Ends: 08:24:35 UT
Partial Eclipse Ends: 09:33:04 UT
Penumbral Eclipse Ends: 10:37:37 UT
At the instant of greatest eclipse[1] (07:45:40 UT) the Moon lies at the zenith for a point in the South Pacific about 3000 km southwest of the Galapagos Islands. The umbral eclipse magnitude[2] peaks at 1.2907 as the Moon's northern limb passes 1.7 arc-minutes south of the shadow's central axis. In contrast, the Moon's southern limb lies 9.0 arc-minutes from the southern edge of the umbra and 40.0 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 umbra. Since the Moon samples a large range of umbral depths during totality, its appearance will change significantly 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 verses south).During totality, the spring constellations are well placed for viewing so a number of bright stars can be used for magnitude comparisons. Spica (m = +1.05) is the most conspicuous star lying just 2° west of the eclipsed Moon. This juxtaposition reminds the author of the total lunar eclipse of 1968 Apr 13 when Spica appeared only 1.3° southwest of the Moon at mid-totality. The brilliant blue color of Spica made for a striking contrast with the crimson Moon. Just a week past opposition, Mars (m = -1.4) appears two magnitudes brighter than Spica and lies 9.5° northwest of the Moon. Arcturus (m = +0.15) is 32° to the north, Saturn (m = +0.2) is 26° to the east, and Antares (m = +1.07) is 44° to the southeast. The entire event is visible from both North and South America. Observers in the western Pacific miss the first half of the eclipse because it occurs before moonrise. Likewise most of Europe and Africa experience moonset just as the eclipse begins. None of the eclipse is visible from north/east Europe, eastern Africa, the Middle East or Central Asia.Table 1 lists predicted umbral immersion and emersion times for 25 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).The April 15 eclipse is the 56th eclipse of Saros[3] 122. This series began on 1022 August 14 and is composed of 74 lunar eclipses in the following sequence: 22 penumbral, 8 partial, 28 total, 7 partial, and 9 penumbral eclipses (Espenak and Meeus, 2009). The last eclipse of the series is on 2338 October 29. Complete details for Saros 122 can be found at:
eclipse.gsfc.nasa.gov/LEsaros/LEsaros122.html
The first eclipse of the year is well placed for observers throughout the Western Hemisphere. The eclipse occurs at the lunar orbit's ascending node in Virgo. The apparent diameter of the Moon is close to its average since the eclipse occurs nearly midway between apogee (April 08 at 14:53 UT) and perigee (April 23 at 00:28 UT). This is the first of four consecutive total lunar eclipses in 2014 and 2015 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 78 minutes. The Moon's path through Earth's shadows as well as a map illustrating worldwide visibility of the event are shown in Figure 1. The times of the major eclipse phases are listed below.
Penumbral Eclipse Begins: 04:53:37 UT
Partial Eclipse Begins: 05:58:19 UT
Total Eclipse Begins: 07:06:47 UT
Greatest Eclipse: 07:45:40 UT
Total Eclipse Ends: 08:24:35 UT
Partial Eclipse Ends: 09:33:04 UT
Penumbral Eclipse Ends: 10:37:37 UT
At the instant of greatest eclipse[1] (07:45:40 UT) the Moon lies at the zenith for a point in the South Pacific about 3000 km southwest of the Galapagos Islands. The umbral eclipse magnitude[2] peaks at 1.2907 as the Moon's northern limb passes 1.7 arc-minutes south of the shadow's central axis. In contrast, the Moon's southern limb lies 9.0 arc-minutes from the southern edge of the umbra and 40.0 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 umbra. Since the Moon samples a large range of umbral depths during totality, its appearance will change significantly 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 verses south).During totality, the spring constellations are well placed for viewing so a number of bright stars can be used for magnitude comparisons. Spica (m = +1.05) is the most conspicuous star lying just 2° west of the eclipsed Moon. This juxtaposition reminds the author of the total lunar eclipse of 1968 Apr 13 when Spica appeared only 1.3° southwest of the Moon at mid-totality. The brilliant blue color of Spica made for a striking contrast with the crimson Moon. Just a week past opposition, Mars (m = -1.4) appears two magnitudes brighter than Spica and lies 9.5° northwest of the Moon. Arcturus (m = +0.15) is 32° to the north, Saturn (m = +0.2) is 26° to the east, and Antares (m = +1.07) is 44° to the southeast. The entire event is visible from both North and South America. Observers in the western Pacific miss the first half of the eclipse because it occurs before moonrise. Likewise most of Europe and Africa experience moonset just as the eclipse begins. None of the eclipse is visible from north/east Europe, eastern Africa, the Middle East or Central Asia.Table 1 lists predicted umbral immersion and emersion times for 25 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).The April 15 eclipse is the 56th eclipse of Saros[3] 122. This series began on 1022 August 14 and is composed of 74 lunar eclipses in the following sequence: 22 penumbral, 8 partial, 28 total, 7 partial, and 9 penumbral eclipses (Espenak and Meeus, 2009). The last eclipse of the series is on 2338 October 29. Complete details for Saros 122 can be found at:
eclipse.gsfc.nasa.gov/LEsaros/LEsaros122.html
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