April 2015 lunar eclipse

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.

April 2015 lunar eclipse
Total eclipse
Date4 April 2015
Gamma0.4460
Magnitude1.0008
Saros cycle132 (30 of 71)
Totality4 minutes, 44 seconds
Partiality209 minutes, 2 seconds
Penumbral357 minutes, 38 seconds

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.

Duration

Totality 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). Due to the oblateness of the Earth, it may have actually just been a partial eclipse.[2] 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'.

Visibility

The 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.


View of earth from moon at greatest eclipse

Map

United States

Asia

Oceania

Background
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.[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
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 4Morning 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:[4]

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.

Eclipses of 2015

Half-Saros cycle

A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros).[5] This lunar eclipse is related to two total solar eclipses of solar saros 139.

March 29, 2006 April 8, 2024

Lunar year series

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.

Saros series

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.[6]		 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

See also

Notes
  1. 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. Fred Espenak and Jean Meeus. "Visual Appearance of Lunar Eclipses". NASA. Retrieved 13 April 2014.
  4. Clarke, Kevin. "On the nature of eclipses". Inconstant Moon. Cyclopedia Selenica. Retrieved 19 December 2010.
  5. Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros
  6. Listing of Eclipses of series 132
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