September 2015 lunar eclipse

A total lunar eclipse took place between 27 and 28 September 2015. It was seen on Sunday evening, 27 September, in the Americas; while in Europe, Africa, and the Middle East, it was seen in the early hours of Monday morning, 28 September. It was the latter of two total lunar eclipses in 2015, and the final in a tetrad (four total lunar eclipses in series). Other eclipses in the tetrad are those of 15 April 2014, 8 October 2014, and 4 April 2015.

Total lunar eclipse
September 28, 2015

From Murrieta, California, 2:52 UTC
Ecliptic north up

The Moon passes right to left (west to east) through Earth's shadow
Saros (and member)137 (28 of 81)
Gamma−0.3296
Magnitude1.2764
Duration (hr:mn:sc)
Totality1:11:55
Partial3:19:52
Penumbral5:10:41
Contacts (UTC)
P10:11:47
U11:07:11
U22:11:10
Greatest2:47:08
U33:23:05
U44:27:03
P45:22:27

The Moon crosses Earth's shadow in Pisces, passing west to east (right to left) as shown here in hourly movements. Uranus, at magnitude 5.7, can be seen in binoculars 16 degrees east of the total eclipsed Moon.

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.[1][2]

The total lunar eclipse was darker than expected, possibly due to ash left behind from eruptions of the Calbuco volcano in April 2015.[3]

Background

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.[4]

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.

Visibility

The eclipse was visible over Europe, the Middle East, Africa, and America.


View of Earth from Moon at greatest eclipse

Simulated appearance of Earth and atmospheric ring of sunlight

Timing

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 SeptemberMorning 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.[5]

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:[6]
  • 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.

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 31 January 2018.

Eclipses of 2015

The eclipse was one of four lunar eclipses in a short-lived series at the descending 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, 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 series

It is part of Saros series 137.

Half-Saros cycle

A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros).[7] This lunar eclipse is related to two annular solar eclipses of solar saros 144.

22 September 2006 2 October 2024

See also

References

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