Wikipedia

April 2015 lunar eclipse

A total lunar eclipse occurred at the Moon’s ascending node of orbit on Saturday, April 4, 2015,[1] with an umbral magnitude of 1.0019. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring about 3.1 days after apogee (on April 1, 2015, at 9:00 UTC), the Moon's apparent diameter was smaller.[2]

April 2015 lunar eclipse
Total eclipse
Totality as viewed from Los Angeles, California, 12:00 UTC
DateApril 4, 2015
Gamma0.4460
Magnitude1.0019
Saros cycle132 (30 of 71)
Totality4 minutes, 43 seconds
Partiality209 minutes, 1 second
Penumbral357 minutes, 31 seconds
Contacts (UTC)
P109:01:27
U110:15:45
U211:57:54
Greatest12:00:15
U312:02:37
U413:44:46
P414:58:58

This lunar eclipse is the third of a tetrad, with four total lunar eclipses in series, the others being on April 15, 2014; October 8, 2014; and September 28, 2015.

This is the 30th member of Lunar Saros 132, and the first total eclipse of the series. The previous event was the March 1997 lunar eclipse, being slightly partial.

Duration

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Totality lasted only 4 minutes and 43 seconds,[3] making it the shortest lunar totality in almost five centuries since October 17, 1529 (which lasted 1 minute and 42 seconds). It was claimed by some that due to the oblateness of the Earth, it may have actually just been a partial eclipse.[4] It 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. The 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 past apogee at 29.42'.

 

Background

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Main article: 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.[5]

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.

 

Visibility

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The eclipse was completely visible over northeast Asia, eastern Australia, the Pacific Ocean, and western North America, seen rising over Asia and western Australia and setting over North and South America.[6]

   
 
Visibility map

Timing

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Local times of contacts
Time Zone
adjustments from
UTC 		+8h +11h +13h -10h -8h -7h -6h -5h -4h
AWST AEDT NZDT HST AKDT PDT MDT CDT EDT
Event Evening April 4 Morning April 4
P1 Penumbral begins N/A† 8:01 pm 10:01 pm 11:01 pm 1:01 am 2:01 am 3:01 am 4:01 am 5:01 am
U1 Partial begins 6:16 pm 9:16 pm 11:16 pm 12:16 am 2:16 am 3:16 am 4:16 am 5:16 am 6:16 am
U2 Total begins 7:58 pm 10:58 pm 12:58 am 1:58 am 3:58 am 4:58 am 5:58 am 6:58 am Set
Greatest eclipse 8:00 pm 11:00 pm 1:00 am 2:00 am 4:00 am 5:00 am 6:00 am 7:00 am Set
U3 Total ends 8:03 pm 11:03 pm 1:03 am 2:03 am 4:03 am 5:03 am 6:03 am Set Set
U4 Partial ends 9:45 pm 12:45 am 2:45 am 3:45 am 5:45 am Set Set Set Set
P4 Penumbral ends 10:59 pm 1:59 am 3:59 am 3:59 am 5:59 am Set Set Set Set

† The Moon was not visible during this part of the eclipse in this time zone.

 
Contact points relative to the Earth's umbral and penumbral shadows, here with the Moon near its descending node.
The timing of total lunar eclipses are determined by its contacts:[7]
  • P1 (First contact): Beginning of the penumbral eclipse. Earth's penumbra touches the Moon's outer limb.
  • U1 (Second contact): Beginning of the partial eclipse. Earth's umbra touches the Moon's outer limb.
  • U2 (Third contact): Beginning of the total eclipse. The Moon's surface is entirely within Earth's umbra.
  • Greatest eclipse: The peak stage of the total eclipse. The Moon is at its closest to the center of Earth's umbra.
  • U3 (Fourth contact): End of the total eclipse. The Moon's outer limb exits Earth's umbra.
  • U4 (Fifth contact): End of the partial eclipse. Earth's umbra leaves the Moon's surface.
  • P4 (Sixth contact): End of the penumbral eclipse. Earth's penumbra no longer makes contact with the Moon.
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Progression from Bali, Indonesia
 
Time-lapsed image from Taiwan 		 
Sequence from Fox Observatory in Sunrise, Florida
 
Sequence from Melbourne, Florida 		 
Progression from St. Louis, Missouri

Eclipse details

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Shown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.[8]

April 4, 2015 Lunar Eclipse Parameters
Parameter Value
Penumbral Magnitude 2.08024
Umbral Magnitude 1.00191
Gamma 0.44599
Sun Right Ascension 00h53m01.2s
Sun Declination +05°40'32.8"
Sun Semi-Diameter 15'59.6"
Sun Equatorial Horizontal Parallax 08.8"
Moon Right Ascension 12h53m29.7s
Moon Declination -05°17'20.2"
Moon Semi-Diameter 14'49.9"
Moon Equatorial Horizontal Parallax 0°54'25.9"
ΔT 67.7 s

Eclipse season

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See also: Eclipse cycle

This eclipse is part of an eclipse season, a period, roughly every six months, when eclipses occur. Only two (or occasionally three) eclipse seasons occur each year, and each season lasts about 35 days and repeats just short of six months (173 days) later; thus two full eclipse seasons always occur each year. Either two or three eclipses happen each eclipse season. In the sequence below, each eclipse is separated by a fortnight.

Eclipse season of March–April 2015
March 20
Descending node (new moon)
 April 4
Ascending node (full moon)
   
Total solar eclipse
Solar Saros 120		 Total lunar eclipse
Lunar Saros 132
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Eclipses in 2015

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Metonic

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Tzolkinex

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Half-Saros

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Tritos

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Lunar Saros 132

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Inex

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Triad

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Lunar eclipses of 2013–2016

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The 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 series sets from 2013–2016
Ascending node   Descending node
Saros Viewing
date 		Type Gamma Saros Viewing
date 		Type Gamma
112
  		2013 Apr 25
  		Partial
  		−1.0121 117
  		2013 Oct 18
  		Penumbral
  		1.1508
122
  		2014 Apr 15
  		Total
  		−0.3017 127
  		2014 Oct 08
  		Total
  		0.3827
132
  		2015 Apr 04
  		Total
  		0.4460 137
  		2015 Sep 28
  		Total
  		−0.3296
142 2016 Mar 23
  		Penumbral
  		1.1592 147
  		2016 Sep 16
  		Penumbral
  		−1.0549
Last set 2013 May 25 Last set 2012 Nov 28
Next set 2017 Feb 11 Next set 2016 Aug 18

Saros 132

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Lunar saros series 132, repeating every 18 years and 11 days, has a total of 71 lunar eclipse events including 44 umbral lunar eclipses (32 partial lunar eclipses and 12 total lunar eclipses).

Greatest First
 
The greatest eclipse of the series will occur on 2123 Jun 9, lasting 106 minutes.[9] 		Penumbral Partial Total Central
1492 May 12
  		1636 Aug 16
  		2015 Apr 4
  		2069 May 6
 
Last
Central Total Partial Penumbral
2177 Jul 11
  		2213 Aug 2
  		2429 Dec 11
  		2754 Jun 26
 

There are 11 series events between 1901 and 2100, grouped into threes (called an exeligmos), each column with approximately the same viewing longitude on earth.

1901–2100
1907 Jan 29 1925 Feb 8 1943 Feb 20
           
1961 Mar 2 1979 Mar 13 1997 Mar 24
           
2015 Apr 4 2033 Apr 14 2051 Apr 26
           
2069 May 6 2087 May 17
       

Half-Saros cycle

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A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros).[10] This lunar eclipse is related to two total solar eclipses of solar saros 139.

March 29, 2006 April 8, 2024
   

See also

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Notes

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  1. ^ "April 4, 2015 Total Lunar Eclipse (Blood Moon)". timeanddate. Retrieved 16 November 2024.
  2. ^ "Moon Distances for London, United Kingdom, England". timeanddate. Retrieved 16 November 2024.
  3. ^ Espenak, Fred. "Total Lunar Eclipse of 2015 Apr 04" (PDF). NASA's GSFC.
  4. ^ "The Lunar Eclipse Wasn't Total After All?!". Sky & Telescope. 6 April 2015.
  5. ^ Fred Espenak and Jean Meeus. "Visual Appearance of Lunar Eclipses". NASA. Retrieved 13 April 2014.
  6. ^ "Total Lunar Eclipse of 2015 Apr 04" (PDF). NASA. Retrieved 16 November 2024.
  7. ^ Clarke, Kevin. "On the nature of eclipses". Inconstant Moon. Cyclopedia Selenica. Retrieved 19 December 2010.
  8. ^ "Total Lunar Eclipse of 2015 Apr 04". EclipseWise.com. Retrieved 16 November 2024.
  9. ^ Listing of Eclipses of series 132
  10. ^ Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros
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