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July 2018 lunar eclipse

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July 2018 lunar eclipse
Total eclipse
Totality as viewed from Oria, Italy, 21:09 UTC
DateJuly 27, 2018
Gamma0.1168
Magnitude1.6100
Saros cycle129 (38 of 71)
Totality102 minutes, 57 seconds
Partiality234 minutes, 33 seconds
Penumbral373 minutes, 48 seconds
Contacts (UTC)
P117:14:49
U118:24:27
U219:30:15
Greatest20:21:44
U321:13:12
U422:19:00
P423:28:37

A total lunar eclipse occurred at the Moon’s descending node of orbit on Friday, July 27, 2018,[1] with an umbral magnitude of 1.6100. It was a central lunar eclipse, in which part of the Moon passed through the center of the Earth's shadow. 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 19 hours after apogee (on July 27, 2018, at 1:45 UTC), the Moon's apparent diameter was smaller.[2]

This was the first central lunar eclipse since June 15, 2011. It was also the longest total lunar eclipse of 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 three hours 54.55 minutes.[8] 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.

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),[9][10] and to travel at its slowest speed in its orbit around Earth.[3]

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

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 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.[11]

The Moon's brightness is exaggerated within the umbral shadow.[11] 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

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The eclipse was completely visible over east Africa, southern Africa, south and central Asia, seen rising over South America, west Africa, and Europe, and setting over east Asia and Australia.[12][13]


Visibility map
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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.[14]

July 27, 2018 Lunar Eclipse Parameters
Parameter Value
Penumbral Magnitude 2.68050
Umbral Magnitude 1.60996
Gamma 0.11681
Sun Right Ascension 08h28m22.0s
Sun Declination +19°04'25.2"
Sun Semi-Diameter 15'45.0"
Sun Equatorial Horizontal Parallax 08.7"
Moon Right Ascension 20h28m18.2s
Moon Declination -18°58'10.6"
Moon Semi-Diameter 14'42.7"
Moon Equatorial Horizontal Parallax 0°53'59.7"
ΔT 68.9 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. The first and last eclipse in this sequence is separated by one synodic month.

Eclipse season of July–August 2018
July 13
Ascending node (new moon)
 July 27
Descending node (full moon)
 August 11
Ascending node (new moon)
Partial solar eclipse
Solar Saros 117		 Total lunar eclipse
Lunar Saros 129		 Partial solar eclipse
Solar Saros 155
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Wide angle view of the total lunar eclipse and Mars in Melbourne, Australia

Eclipses in 2018

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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 129

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Inex

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Triad

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Lunar eclipses of 2016–2020

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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.[15]

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 129

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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.[16]

Greatest First

The greatest eclipse of the series occurred on 2000 Jul 16, lasting 106 minutes, 24 seconds.[17] 		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.

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).[18] This lunar eclipse is related to two total solar eclipses of Solar Saros 136.

July 22, 2009 August 22, 2027

See also

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Notes

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  1. ^ "July 27–28, 2018 Total Lunar Eclipse (Blood Moon)". timeanddate. Retrieved 17 November 2024.
  2. ^ "Moon Distances for London, United Kingdom, England". timeanddate. Retrieved 17 November 2024.
  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. ^ "What Is a Micromoon?". Timeanddate.com. Stavanger, Norway: Time and Date AS. n.d. Retrieved 27 July 2018.
  10. ^ 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.
  11. ^ 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.
  12. ^ "Total Lunar Eclipse of 2018 Jul 27" (PDF). NASA. Retrieved 17 November 2024.
  13. ^ "Eclipse Map — 27 July 2018 Total Lunar Eclipse".
  14. ^ "Total Lunar Eclipse of 2018 Jul 27". EclipseWise.com. Retrieved 17 November 2024.
  15. ^ 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.
  16. ^ "NASA - Catalog of Lunar Eclipses of Saros 129". eclipse.gsfc.nasa.gov.
  17. ^ Listing of Eclipses of series 129
  18. ^ Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros
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