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July 2018 lunar eclipse

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Total lunar eclipse
27 July 2018

Oria, Italy, 21:09 UTC, end of totality
Ecliptic north up

The moon passed through the center of the Earth's shadow
Saros cycle 129 (38 of 71)
Gamma +0.1168
Duration (hr:mn:sc)
Totality 1:42:57
Partial 3:54:32
Penumbral 6:13:48
Contacts (UTC)
P1 17:14:49
U1 18:24:27
U2 19:30:15
Greatest 20:21:44
U3 21:13:12
U4 22:19:00
P4 23:28:39

A total lunar eclipse occurred at the Moon’s descending node on 27 July 2018. The Moon passed through the center of Earth's shadow in what was the first central lunar eclipse since 15 June 2011. It was also the second total lunar eclipse in 2018, after the one on 31 January. It was the longest total lunar eclipse of the 21st century, but not the longest in the 3rd millennium. The longest total lunar eclipse of the 3rd millennium will occur on May 12, 2264, lasting 106 minutes and 13.2 seconds.

The eclipse occurred when the Moon was near its maximum distance from Earth, which caused the Moon to appear smaller than normal (a phenomenon sometimes called a micromoon),[1][2] and to travel at its slowest speed in its orbit around Earth.[3] This was the longest total lunar eclipse that will occur in the 21st century, but not the longest in the 3rd millennium.[3] Totality lasted one hour and 42.955 minutes,[4][5][6][7] a period "just short of the theoretical limit of a lunar eclipse (one hour and 46.605 minutes)".[8] The Moon remained at least partially in Earth's shadow for four hours.[8]

This lunar eclipse coincided with Mars being nearly as close as possible to Earth, a concurrence that happens once every 25,000 years.[6]

A total lunar eclipse occurred on July 27, 2018. This was the longest total lunar eclipse exclusively in the 21st century, but the longest total lunar eclipse of the 3rd millennium will occur on May 12, 2264, lasting 106 minutes and 13.2 seconds, which will be the longest total lunar eclipse since 2000, and the longest one until 3107.

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 Earth's shadow begins to cover part of the Moon, typically turning it a dark red-brown color (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 daytime sky to appear blue) and the refraction of that light by Earth's atmosphere into its umbra.[9]

The Moon's brightness is exaggerated within the umbral shadow.[9] The southern portion of the Moon was closest to the center of the shadow, making it the darkest, and most red in appearance.[citation needed]

Animation showing the approximate appearance of the Moon passing through Earth's shadow

Visibility

Wide angle view of the total lunar eclipse and Mars in Melbourne, Australia
Sequence of the lunar eclipse seen from Davao City, Philippines

The lunar eclipse was completely visible over Eastern Africa, Southern Africa, Southern Asia and Central Asia, seen rising over South America, Western Africa, and Europe, and setting over East Asia, and Australia.[10]


View of earth from moon at greatest eclipse

Map

Observations

Eclipses of 2018

Lunar year series

This eclipse is a member of a semester series. An eclipse in a semester series of lunar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternating nodes of the Moon's orbit.[11]

The penumbral lunar eclipses on March 23, 2016 and September 16, 2016 occur in the previous lunar year eclipse set, and the penumbral lunar eclipses on June 5, 2020 and November 30, 2020 occur in the next lunar year eclipse set.

Lunar eclipse series sets from 2016 to 2020
Descending node   Ascending node
Saros Date
Viewing
Type
Chart
Gamma Saros Date
Viewing
Type
Chart
Gamma
109 2016 Aug 18
Penumbral
1.5641 114
2017 Feb 11
Penumbral
−1.0255
119
2017 Aug 07
Partial
0.8669 124
2018 Jan 31
Total
−0.3014
129
2018 Jul 27
Total
0.1168 134
2019 Jan 21
Total
0.3684
139
2019 Jul 16
Partial
−0.6430 144
2020 Jan 10
Penumbral
1.0727
149 2020 Jul 05
Penumbral
−1.3639

Saros series

This eclipse is a part of Saros series 129, repeating every 18 years, 11 days, and containing 71 events. The series started with a penumbral lunar eclipse on June 10, 1351. It contains partial eclipses from September 26, 1531 through May 11, 1892; total eclipses from May 24, 1910 through September 8, 2090; and a second set of partial eclipses from September 20, 2108 through April 26, 2469. The series ends at member 71 as a penumbral eclipse on July 24, 2613.

The longest duration of totality was produced by member 37 at 106 minutes, 24 seconds on July 16, 2000. All eclipses in this series occur at the Moon’s descending node of orbit.[12]

Greatest First

The greatest eclipse of the series occurred on 2000 Jul 16, lasting 106 minutes, 24 seconds.[13]
Penumbral Partial Total Central
1351 Jun 10
1531 Sep 26
1910 May 24
1946 Jun 14
Last
Central Total Partial Penumbral
2036 Aug 07
2090 Sep 08
2469 Apr 26
2613 Jul 24

Eclipses are tabulated in three columns; every third eclipse in the same column is one exeligmos apart, so they all cast shadows over approximately the same parts of the Earth.

It last occurred on July 16, 2000 and will next occur on August 7, 2036.

This is the 38th member of Lunar Saros 129. The previous event was the July 2000 lunar eclipse. The next event is the August 2036 lunar eclipse. Lunar Saros 129 contains 11 total lunar eclipses between 1910 and 2090. Solar Saros 136 interleaves with this lunar saros with an event occurring every 9 years 5 days alternating between each saros series.

Half-Saros cycle

A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros).[14] This lunar eclipse is related to two total solar eclipses of Solar Saros 136.

July 22, 2009 August 2, 2027

Inex

Tritos

Tzolkinex

Half-Saros cycle

See also

Notes

  1. ^ "What Is a Micromoon?". Timeanddate.com. Stavanger, Norway: Time and Date AS. n.d. Retrieved 27 July 2018.
  2. ^ Mosher, Dave; Gal, Shayanne (27 July 2018). "The longest total lunar eclipse in a century is about to happen — here's how Earth will color the moon blood-red". Business Insider. Retrieved 27 July 2018.
  3. ^ a b McClure, Bruce (27 July 2018). "Century's Longest Lunar Eclipse July 27". EarthSky. Retrieved 27 July 2018.
  4. ^ Space (29 December 2017). "In 2018 the longest lunar eclipse will take place in 100 years". Earth Chronicles. Retrieved 27 July 2018.
  5. ^ Resnick, Brian (27 July 2018). "Watch: The longest 'blood moon' lunar eclipse of the century". Vox. Retrieved 27 July 2018.
  6. ^ a b Nunamaker, Susan Sun (27 July 2018). "Century's Longest Lunar Eclipse, Blood Moon 2018, Today, Will Last 103 Minutes". Windermere Sun. Retrieved 27 July 2018.
  7. ^ "Два редких астрономических явления можно будет наблюдать 27 июля". TASS (in Russian). 27 July 2018. Retrieved 27 July 2018.
  8. ^ a b Lyons, Kate (27 July 2018). "Blood moon: All you need to know about this week's lunar eclipse". The Guardian. Retrieved 27 July 2018.
  9. ^ a b Espenak, Fred; Meeus, Jean (27 July 2018). "Visual Appearance of Lunar Eclipses". NASA Eclipse Web Site. National Aeronautics and Space Administration. Retrieved 27 July 2018.
  10. ^ "Eclipse Map — 27 July 2018 Total Lunar Eclipse".
  11. ^ van Gent, R.H. "Solar- and Lunar-Eclipse Predictions from Antiquity to the Present". A Catalogue of Eclipse Cycles. Utrecht University. Retrieved 6 October 2018.
  12. ^ "NASA - Catalog of Lunar Eclipses of Saros 129". eclipse.gsfc.nasa.gov.
  13. ^ Listing of Eclipses of series 129
  14. ^ Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros