Wikipedia

September 2015 lunar eclipse

A total lunar eclipse occurred at the Moon’s descending node of orbit on Monday, September 28, 2015,[1] with an umbral magnitude of 1.2774. 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 only about 5 hours after perigee (on September 27, 2015, at 21:45 UTC), the Moon's apparent diameter was larger.[2]

September 2015 lunar eclipse
Total eclipse
Totality as viewed from Murrieta, California, 2:52 UTC
DateSeptember 28, 2015
Gamma−0.3296
Magnitude1.2774
Saros cycle137 (28 of 81)
Totality71 minutes, 55 seconds
Partiality199 minutes, 52 seconds
Penumbral310 minutes, 41 seconds
Contacts (UTC)
P10:11:47
U11:07:11
U22:11:10
Greatest2:47:08
U33:23:05
U44:27:03
P45:22:27

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 April 4, 2015.

The Moon appeared larger than normal, because the Moon was just 1 hour past its closest approach to Earth in 2015 at mid-eclipse, sometimes called a supermoon. The Moon's apparent diameter was larger than 34' viewed straight overhead, just off the coast of northeast Brazil.[3][4]

The total lunar eclipse was darker than expected, possibly due to ash left behind from eruptions of the Calbuco volcano in April 2015.[5]

Background

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Main article: Lunar eclipse
This animated video explains the September 2015 supermoon 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.[6]

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 northern portion of the Moon was closest to the center of the shadow, making it darkest, and most red in appearance.

 


Supermoon

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Further information: Supermoon

This eclipsed Moon appeared 12.9% larger in diameter than the April 2015 lunar eclipse, measured as 29.66' and 33.47' in diameter from Earth's center, as compared in these simulated images.

A supermoon is the coincidence of a full moon or a new moon with the closest approach the Moon makes to the Earth on its elliptical orbit, resulting in the largest apparent size of the lunar disk as seen from Earth. This was the last supermoon lunar eclipse until January 31, 2018.

 

Visibility

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The eclipse was completely visible over eastern North America, South America, west Africa, and western Europe, seen rising over western North America and the eastern Pacific Ocean and setting over east Africa, eastern Europe, and west and central Asia.[7]

   
Hourly motion shown right to left 		 
Simulated appearance of Earth and atmospheric ring of sunlight 		 
The Moon's hourly motion across the Earth's shadow in the constellation of Pisces.
 
Visibility map

Timing

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Local times of contacts
Time Zone
adjustments from
UTC 		-7h -6h -5h -4h -3h -2h -1h 0h +1h +2h +3h
PDT
MST 		MDT CDT
PET 		EDT
BOT 		ADT
AMST
ART 		GMT
WET 		WEST
CET
BST 		CEST
EET
MSK−1 		EEST
FET
MSK
Event Evening 27 September Morning 28 September
P1 Penumbral begins* N/A† N/A† 7:12 pm 8:12 pm 9:12 pm 10:12 pm 11:12 pm 12:12 am 1:12 am 2:12 am 3:12 am
U1 Partial begins N/A† 7:07 pm 8:07 pm 9:07 pm 10:07 pm 11:07 pm 12:07 am 1:07 am 2:07 am 3:07 am 4:07 am
U2 Total begins 7:11 pm 8:11 pm 9:11 pm 10:11 pm 11:11 pm 12:11 am 1:11 am 2:11 am 3:11 am 4:11 am 5:11 am
Mid-eclipse 7:47 pm 8:47 pm 9:47 pm 10:47 pm 11:47 pm 12:47 am 1:47 am 2:47 am 3:47 am 4:47 am 5:47 am
U3 Total ends 8:23 pm 9:23 pm 10:23 pm 11:23 pm 12:23 am 1:23 am 2:23 am 3:23 am 4:23 am 5:23 am 6:23 am
U4 Partial ends 9:27 pm 10:27 pm 11:27 pm 12:27 am 1:27 am 2:27 am 3:27 am 4:27 am 5:27 am 6:27 am Set
P4 Penumbral ends 10:22 pm 11:22 pm 12:22 am 1:22 am 2:22 am 3:22 am 4:22 am 5:22 am 6:22 am Set Set

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

* The penumbral phase of the eclipse changes the appearance of the Moon only slightly and is generally not noticeable.[8]

 
Contact points relative to 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:[9]
  • 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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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.[10]

September 28, 2015 Lunar Eclipse Parameters
Parameter Value
Penumbral Magnitude 2.23071
Umbral Magnitude 1.27744
Gamma −0.32960
Sun Right Ascension 12h17m08.9s
Sun Declination -01°51'20.9"
Sun Semi-Diameter 15'57.6"
Sun Equatorial Horizontal Parallax 08.8"
Moon Right Ascension 00h17m33.6s
Moon Declination +01°32'03.6"
Moon Semi-Diameter 16'44.5"
Moon Equatorial Horizontal Parallax 1°01'26.6"
ΔT 67.8 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 September 2015
September 13
Ascending node (new moon)
 September 28
Descending node (full moon)
   
Partial solar eclipse
Solar Saros 125		 Total lunar eclipse
Lunar Saros 137
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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 137

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Inex

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Triad

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Lunar eclipses of 2013–2016

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The lunar year series repeats after 12 lunations, or 354 days (shifting back about 10 days in sequential years). Because of the date shift, 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 137

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It is part of Saros series 137.

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).[11] This lunar eclipse is related to two annular solar eclipses of solar saros 144.

September 22, 2006 October 2, 2024
   

See also

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References

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  1. ^ "September 27–28, 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. ^ Sky and Telescope
  4. ^ Here’s the Scoop on Sunday’s Supermoon Eclipse, Bob King
  5. ^ "Why Was September's Lunar Eclipse So Dark? - Universe Today". Universe Today. 5 October 2015. Retrieved 8 August 2017.
  6. ^ Fred Espenak & Jean Meeus. "Visual Appearance of Lunar Eclipses". NASA. Retrieved 13 April 2014.
  7. ^ "Total Lunar Eclipse of 2015 Sep 28" (PDF). NASA. Retrieved 16 November 2024.
  8. ^ Espenak, Fred. "Lunar Eclipses for Beginners". MrEclipse. Retrieved 7 April 2014.
  9. ^ Clarke, Kevin. "On the nature of eclipses". Inconstant Moon. Cyclopedia Selenica. Retrieved 19 December 2010.
  10. ^ "Total Lunar Eclipse of 2015 Sep 28". EclipseWise.com. Retrieved 16 November 2024.
  11. ^ Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros
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