A total lunar eclipse occurred at the Moon’s descending node of orbit on Friday, July 27, 2018, 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.
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. Totality lasted one hour and 42.955 minutes, a period "just short of the theoretical limit of a lunar eclipse (one hour and 46.605 minutes)". The Moon remained at least partially in Earth's shadow for three hours 54.55 minutes. 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), and to travel at its slowest speed in its orbit around Earth.
This lunar eclipse coincided with Mars being nearly as close as possible to Earth, a concurrence that happens once every 25,000 years.
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.
The Moon's brightness is exaggerated within the umbral shadow. The southern portion of the Moon was closest to the center of the shadow, making it the darkest, and most red in appearance.
Visibility 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.
Visibility map
Gallery
Eclipse details Shown below is a table displaying details about this particular lunar eclipse. It describes various parameters pertaining to this eclipse.
+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
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 13Ascending node (new moon) July 27Descending node (full moon) August 11Ascending node (new moon) Partial solar eclipseSolar Saros 117 Total lunar eclipseLunar Saros 129 Partial solar eclipseSolar Saros 155
Related eclipses
Eclipses in 2018 A total lunar eclipse on January 31. A partial solar eclipse on February 15. A partial solar eclipse on July 13. A total lunar eclipse on July 27. A partial solar eclipse on August 11.
Metonic Preceded by: Lunar eclipse of October 8, 2014 Followed by: Lunar eclipse of May 16, 2022
Tzolkinex Preceded by: Lunar eclipse of June 15, 2011 Followed by: Lunar eclipse of September 7, 2025
Half-Saros Preceded by: Solar eclipse of July 22, 2009 Followed by: Solar eclipse of August 2, 2027
Tritos Preceded by: Lunar eclipse of August 28, 2007 Followed by: Lunar eclipse of June 26, 2029
Lunar Saros 129 Preceded by: Lunar eclipse of July 16, 2000 Followed by: Lunar eclipse of August 7, 2036
Inex Preceded by: Lunar eclipse of August 17, 1989 Followed by: Lunar eclipse of July 7, 2047
Triad Preceded by: Lunar eclipse of September 26, 1931 Followed by: Lunar eclipse of May 28, 2105
Lunar eclipses of 2016–2020
Saros 129
Tritos series
Inex 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).Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros This lunar eclipse is related to two total solar eclipses of Solar Saros 136. July 22, 2009August 2, 2027
See also List of lunar eclipses and List of 21st-century lunar eclipses
Notes
External links
Where to see the eclipse and public events (Go Stargazing)
Hermit eclipse: 2018-07-27 Photo Reveals a Lunar Eclipse Like Never Before