| 词条 | April 2015 lunar eclipse | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 释义 |
A total lunar eclipse took place on 4 April 2015. It is the former of two total lunar eclipses in 2015, and the third in a tetrad (four total lunar eclipses in series). Other eclipses in the tetrad are those of 15 April 2014, 8 October 2014, and 28 September 2015. This is the 30th member of Lunar Saros 132, and the first total eclipse. The previous event was the March 1997 lunar eclipse, being slightly partial. DurationTotality lasted only 4 minutes and 44 seconds,[1] making it the shortest lunar totality in almost five centuries since 17 October 1529 (which lasted 1 minute and 42 seconds). Another shortest occurs on December 28 1917, lasting (11 minutes and 58 seconds). The next very short lunar totality will occur on 26 May 2021 (which will last 14 minutes and 24 seconds). This was the sixth total lunar eclipse out of nine with totality under 5 minutes in a five millennium period between 2,000 BC and 3,000 AD. However, due to the oblateness of the Earth, this lunar eclipse may have actually been (barely) a partial eclipse.[2] This eclipsed moon was 12.9% smaller in apparent diameter than the supermoon September 2015 lunar eclipse, measured as 29.66' and 33.47' in diameter from the center of the earth. It occurred 3 days before apogee at 29.42'. VisibilityThe eclipse was visible across the Pacific, including all of Australia and New Zealand. It was visible near sunrise for North America, and after sunset for eastern Asia including India.
MapGalleryUnited StatesAsiaOceaniaBackground{{main|Lunar eclipse}}A lunar eclipse occurs when the Moon passes within Earth's umbra (shadow). As the eclipse begins, Earth's shadow first darkens the Moon slightly. Then, the shadow begins to "cover" part of the Moon, turning it a dark red-brown color (typically - the color can vary based on atmospheric conditions). The Moon appears to be reddish because of Rayleigh scattering (the same effect that causes sunsets to appear reddish) and the refraction of that light by Earth's atmosphere into its umbra.[3] The following simulation shows the approximate appearance of the Moon passing through Earth's shadow. The Moon's brightness is exaggerated within the umbral shadow. The southern portion of the Moon will be closest to the center of the shadow, making it darkest, and most red in appearance. Timing
† The Moon was not visible during this part of the eclipse in this time zone. {{Total lunar eclipse contacts}}{{Clear}}Related eclipsesHalf-Saros cycleA lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros).[4] This lunar eclipse is related to two total solar eclipses of solar saros 139.
Lunar year seriesThe eclipse is the one of four lunar eclipses in a short-lived series at the ascending node of the moon's orbit. The lunar year series repeats after 12 lunations, or 354 days (shifting back about 10 days in sequential years). Because of the date shift, the Earth's shadow will be about 11 degrees west in sequential events. {{Lunar eclipse set 2013-2016}}Saros series{{Lunar Saros 132 summary}}See also
Notes1. ^http://eclipse.gsfc.nasa.gov/LEplot/LEplot2001/LE2015Apr04T.pdf 2. ^http://www.skyandtelescope.com/astronomy-news/observing-news/the-lunar-eclipse-wasnt-total-after-all-04062015/ 3. ^{{cite web|title=Visual Appearance of Lunar Eclipses|work=NASA|author=Fred Espenak and Jean Meeus|url=http://eclipse.gsfc.nasa.gov/LEcat5/appearance.html|accessdate=April 13, 2014}} 4. ^Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros External links{{Commons category|Lunar eclipse of 2015 April 4}}
3 : 21st-century lunar eclipses|2015 in science|April 2015 events |
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