January 2018 lunar eclipse

January 2018 lunar eclipse
Total eclipse
Totality as viewed from Lomita, California
DateJanuary 31, 2018
Gamma−0.3014
Magnitude1.3155
Saros cycle124 (49 of 74)
Totality76 minutes, 4 seconds
Partiality202 minutes, 44 seconds
Penumbral317 minutes, 12 seconds
Contacts (UTC)
P110:51:15
U111:48:27
U212:51:47
Greatest13:29:50
U314:07:51
U415:11:11
P416:08:27

A total lunar eclipse occurred at the Moon’s ascending node of orbit on Wednesday, January 31, 2018,[1] with an umbral magnitude of 1.3155. 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 1.4 days after perigee (on January 30, 2018, at 4:55 UTC), the Moon's apparent diameter was larger.[2]

Because the Moon was near its perigee on January 30, it may be described as a "supermoon", when the Moon's distance from the Earth is less than 360,000 km (223,694 miles). The previous supermoon lunar eclipse was on September 28, 2015.[3] The Moon was 360,202 km (223,819 mi) from the Earth. This eclipse also coincided with a blue moon, which occurs when there are two full moons in the same calendar month, or if there are four full moons in the same season (third of four is blue moon). As this supermoon was also a blue moon (the second full moon in a calendar month), it was referred to as a "super blue blood moon"; "blood" refers to the typical red color of the Moon during a total lunar eclipse. This event was called a 'Trifecta'.[4] This coincidence last occurred on December 30, 1982 for the eastern hemisphere,[5] and otherwise before that on March 31, 1866.[6][7] The next occurrence will be on January 31, 2037, one metonic cycle (19 years) later.

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.[8]

The following simulation shows the approximate appearance of the Moon passing through Earth's shadow. The northern portion of the Moon is closest to the center of the shadow, making it darkest and reddest in appearance.

"Super blue blood moon"

This was a "supermoon", as the Moon was near to its closest distance to earth in its elliptical orbit, making it 7% larger in apparent diameter or 14% larger in area, than an average full moon. The previous supermoon lunar eclipse was during the September 2015 lunar eclipse.[3]

The full moon of January 31, 2018 was the second full moon that calendar month (in most time zones), making it, under one definition of the term, a "blue moon".

Additionally referencing the orange or red "blood" colors that occur during a lunar eclipse, media sources described the event as a "super blue blood Moon".[9]

Characteristics

Visibility

The Pacific Ocean was turned toward the Moon at the time of the eclipse. Central and eastern Asia (including most of Siberia), Philippines, Indonesia, New Zealand and most of Australia got a good view of this moon show in the evening sky. For Western Asia, the Indian subcontinent, the Middle East and Eastern Europe, the eclipse was underway as the moon rose.[10]

Along the U.S. West Coast, the total phase began at 4:51 a.m. PST. The further east, the closer the start of the partial phases coincided with moonset. Along the U.S. Atlantic Seaboard, for instance, the Moon had only just begun to enter the darkest part of Earth's shadow, the umbra, at 6:48 a.m. EST when it disappeared from view below the west-northwest horizon. The duration of the total phase was 77 minutes, with the Moon tracking through the southern part of the Earth's shadow. During totality, the Moon's lower limb appeared brighter than the dark upper limb.[10]


Visibility map

Timing

Event timing by time zone
Eclipse HST AKST PST MST CST EST UTC MSK IST ICT CST JST AEDT NZDT
Zone from UTC −10 h −9 h −8 h −7 h −6 h −5 h 0 h +3 h +5½ h +7 h +8 h +9 h +11 h +13 h
Penumbral eclipse begins 00:51 01:51 02:51 03:51 04:51 05:51 10:51 13:51 — 17:51 18:51 19:51 21:51 23:51
Partial eclipse begins 01:48 02:48 03:48 04:48 05:48 06:48 11:48 14:48 17:18 18:48 19:48 20:48 22:48 00:48
Total eclipse begins 02:52 03:52 04:52 05:52 06:52 — 12:52 15:52 18:22 19:52 20:52 21:52 23:52 01:52
Mid-eclipse 03:30 04:30 05:30 06:30 — — 13:30 16:30 19:00 20:30 21:30 22:30 00:30 02:30
Total eclipse ends 04:08 05:08 06:08 07:08 — — 14:08 17:08 19:38 21:08 22:08 23:08 01:08 03:08
Partial eclipse ends 05:11 06:11 07:11 — — — 15:11 18:11 20:41 22:11 23:11 00:11 02:11 04:11
Penumbral eclipse ends 06:08 07:08 — — — — 16:08 19:08 21:38 23:08 00:08 01:08 03:08 05:08
  • Example in Aichi Prefecture, Japan: Penumbral lunar eclipse 20:23 (JST) Partial lunar eclipse 21:13 (JST) Partial lunar eclipse 21:43 (JST) Total lunar eclipse (blood moon) 21:55 (JST)
    Example in Aichi Prefecture, Japan:
    1. Penumbral lunar eclipse 20:23 (JST)
    2. Partial lunar eclipse 21:13 (JST)
    3. Partial lunar eclipse 21:43 (JST)
    4. Total lunar eclipse (blood moon) 21:55 (JST)

North America

Asia and Middle East

Oceania

Eclipse details

Shown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.[11]

January 31, 2018 Lunar Eclipse Parameters
Parameter Value
Penumbral Magnitude 2.29538
Umbral Magnitude 1.31671
Gamma −0.30143
Sun Right Ascension 20h56m18.8s
Sun Declination -17°17'47.0"
Sun Semi-Diameter 16'14.0"
Sun Equatorial Horizontal Parallax 08.9"
Moon Right Ascension 08h56m05.0s
Moon Declination +16°59'44.2"
Moon Semi-Diameter 16'35.2"
Moon Equatorial Horizontal Parallax 1°00'52.6"
ΔT 68.8 s

Eclipse season

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.

Eclipse season of January–February 2018
January 31
Ascending node (full moon)
 February 15
Descending node (new moon)
Total lunar eclipse
Lunar Saros 124		 Partial solar eclipse
Solar Saros 150

Eclipses in 2018

Metonic

Tzolkinex

Half-Saros

Tritos

Lunar Saros 124

Inex

Triad

Lunar eclipses of 2016–2020

The January 2018 lunar eclipse is the first ascending node eclipse of the lunar eclipse series sets from 2016 to 2020. It is also part of Saros cycle 124.

Lunar eclipse series sets from 2016–2020
Descending node   Ascending node
Saros Date Type
Viewing 		Gamma Saros Date
Viewing 		Type
Chart 		Gamma
109 2016 Aug 18
 Penumbral
 1.56406 114
 2017 Feb 11
 Penumbral
 −1.02548
119
 2017 Aug 07
 Partial
 0.86690 124
 2018 Jan 31
 Total
 −0.30143
129
 2018 Jul 27
 Total
 0.11681 134
 2019 Jan 21
 Total
 0.36842
139
 2019 Jul 16
 Partial
 −0.64300 144
 2020 Jan 10
 Penumbral
 1.07270
149 2020 Jul 05
 Penumbral
 −1.36387
Last set 2016 Sep 16 Last set 2016 Mar 23
Next set 2020 Jun 05 Next set 2020 Nov 30

A similar eclipse occurs on 31 January 2037, one metonic cycle of 19 years in the future.

Half-Saros cycle

A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros).[12] This lunar eclipse is related to two annular solar eclipses of Solar Saros 131.

January 26, 2009 February 6, 2027

See also

References

  1. ^ "January 31–February 1, 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 Super Blue Moon eclipse on January 31, Earthsky.org, January 30 2018
  4. ^ "'Super Blue Blood Moon' Coming Jan. 31, 2018". NASA. 18 January 2018. Retrieved 1 February 2018.
  5. ^ Blue moon, based on the previous full moon, was either on November 30 or December 1, 1982, based on time zones.
  6. ^ Rare 'Super Blue Blood Moon' Coming—First in 35 Years, National Geographic, January 29, 2018
  7. ^ Mathewson, Samantha (30 January 2018). "The Super Blue Blood Moon Wednesday Is Something the US Hasn't Seen Since 1866". Space.com. Retrieved 1 February 2018.
  8. ^ Fred Espenak & Jean Meeus. "Visual Appearance of Lunar Eclipses". NASA. Retrieved 13 April 2014.
  9. ^ Gill, Victoria (31 January 2018). "Skywatchers see 'super blue blood Moon'". BBC News. Retrieved 1 February 2018.
  10. ^ a b Rao, Joe. "First Blue Moon Total Lunar Eclipse in 150 Years Coming This Month". Space.com. Retrieved 2 January 2018.
  11. ^ "Total Lunar Eclipse of 2018 Jan 31". EclipseWise.com. Retrieved 17 November 2024.
  12. ^ Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros
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