May 1920 lunar eclipse

A total lunar eclipse occurred at the Moon’s ascending node of orbit on Monday, May 3, 1920,^[1] with an umbral magnitude of 1.2194. 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 only about 3.8 days before apogee (on May 6, 1920, at 21:00 UTC), the Moon's apparent diameter was smaller.^[2]

May 1920 lunar eclipse

Total eclipse
The Moon's hourly motion shown right to left
Date	May 3, 1920
Gamma	−0.3312
Magnitude	1.2194
Saros cycle	120 (53 of 84)
Totality	71 minutes, 31 seconds
Partiality	219 minutes, 39 seconds
Penumbral	360 minutes, 4 seconds
Contacts (UTC) P1 22:50:47 U1 0:00:56 U2 1:15:01 Greatest 1:50:47 U3 2:26:32 U4 3:40:36 P4 4:50:51
← November 1919 October 1920 →

This lunar eclipse was the first of an almost tetrad, with the others being on October 27, 1920 (total); April 22, 1921 (total); and October 16, 1921 (partial).

Visibility

The eclipse was completely visible over South America, west and southern Africa, western Europe, and Antarctica, seen rising over much of North America and the eastern Pacific Ocean and setting over eastern Europe, east Africa, and the western half of Asia.^[3]

Eclipse details

Shown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.^[4]

May 3, 1920 Lunar Eclipse Parameters

Parameter	Value
Penumbral Magnitude	2.28178
Umbral Magnitude	1.21939
Gamma	−0.33118
Sun Right Ascension	02h39m30.8s
Sun Declination	+15°32'26.3"
Sun Semi-Diameter	15'51.7"
Sun Equatorial Horizontal Parallax	08.7"
Moon Right Ascension	14h39m15.0s
Moon Declination	-15°50'11.0"
Moon Semi-Diameter	14'55.8"
Moon Equatorial Horizontal Parallax	0°54'47.6"
ΔT	21.5 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 May 1920

May 3 Ascending node (full moon)	May 18 Descending node (new moon)
Total lunar eclipse Lunar Saros 120	Partial solar eclipse Solar Saros 146

Related eclipses

Eclipses in 1920

• A total lunar eclipse on May 3.
• A partial solar eclipse on May 18.
• A total lunar eclipse on October 27.
• A partial solar eclipse on November 10.

Metonic

• Preceded by: Lunar eclipse of July 15, 1916
• Followed by: Lunar eclipse of February 20, 1924

Tzolkinex

• Preceded by: Lunar eclipse of March 22, 1913
• Followed by: Lunar eclipse of June 15, 1927

Half-Saros

• Preceded by: Solar eclipse of April 28, 1911
• Followed by: Solar eclipse of May 9, 1929

Tritos

• Preceded by: Lunar eclipse of June 4, 1909
• Followed by: Lunar eclipse of April 2, 1931

Lunar Saros 120

• Preceded by: Lunar eclipse of April 22, 1902
• Followed by: Lunar eclipse of May 14, 1938

Inex

• Preceded by: Lunar eclipse of May 23, 1891
• Followed by: Lunar eclipse of April 13, 1949

Triad

• Preceded by: Lunar eclipse of July 2, 1833
• Followed by: Lunar eclipse of March 3, 2007

Lunar eclipses of 1919–1922

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.^[5]

The penumbral lunar eclipse on March 13, 1922 occurs in the next lunar year eclipse set.

Lunar eclipse series sets from 1919 to 1922
Ascending node					Descending node
Saros	Date Viewing	Type Chart	Gamma		Saros	Date Viewing	Type Chart	Gamma
110	1919 May 15	Penumbral	−1.0820		115	1919 Nov 07	Partial	0.9246
120	1920 May 03	Total	−0.3312		125	1920 Oct 27	Total	0.2502
130	1921 Apr 22	Total	0.4269		135	1921 Oct 16	Partial	−0.4902
140	1922 Apr 11	Penumbral	1.1228		145	1922 Oct 06	Penumbral	−1.2348

Saros 120

This eclipse is a part of Saros series 120, repeating every 18 years, 11 days, and containing 83 events. The series started with a penumbral lunar eclipse on October 16, 1000. It contains partial eclipses from May 31, 1379 through August 4, 1487; total eclipses from August 14, 1505 through May 14, 1938; and a second set of partial eclipses from May 24, 1956 through July 28, 2064. The series ends at member 83 as a penumbral eclipse on April 7, 2479.

The longest duration of totality was produced by member 43 at 104 minutes, 55 seconds on January 24, 1758. All eclipses in this series occur at the Moon’s ascending node of orbit.^[6]

Greatest	First
The greatest eclipse of the series occurred on 1758 Jan 24, lasting 104 minutes, 55 seconds.[7]	Penumbral	Partial	Total	Central
	1000 Oct 16	1379 May 31	1505 Aug 14	1559 Sep 16
	Last
	Central	Total	Partial	Penumbral
	1902 Apr 22	1938 May 14	2064 Jul 28	2479 Apr 07

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.

Series members 46–67 occur between 1801 and 2200:
46		47		48
1812 Feb 27		1830 Mar 09		1848 Mar 19
49		50		51
1866 Mar 31		1884 Apr 10		1902 Apr 22
52		53		54
1920 May 03		1938 May 14		1956 May 24
55		56		57
1974 Jun 04		1992 Jun 15		2010 Jun 26
58		59		60
2028 Jul 06		2046 Jul 18		2064 Jul 28
61		62		63
2082 Aug 08		2100 Aug 19		2118 Aug 31
64		65		66
2136 Sep 10		2154 Sep 21		2172 Oct 02
67
2190 Oct 13

Tritos series

This eclipse is a part of a tritos cycle, repeating at alternating nodes every 135 synodic months (≈ 3986.63 days, or 11 years minus 1 month). Their appearance and longitude are irregular due to a lack of synchronization with the anomalistic month (period of perigee), but groupings of 3 tritos cycles (≈ 33 years minus 3 months) come close (≈ 434.044 anomalistic months), so eclipses are similar in these groupings.

Series members between 1801 and 2200
1811 Mar 10 (Saros 110)		1822 Feb 06 (Saros 111)		1833 Jan 06 (Saros 112)		1843 Dec 07 (Saros 113)		1854 Nov 04 (Saros 114)
1865 Oct 04 (Saros 115)		1876 Sep 03 (Saros 116)		1887 Aug 03 (Saros 117)		1898 Jul 03 (Saros 118)		1909 Jun 04 (Saros 119)
1920 May 03 (Saros 120)		1931 Apr 02 (Saros 121)		1942 Mar 03 (Saros 122)		1953 Jan 29 (Saros 123)		1963 Dec 30 (Saros 124)
1974 Nov 29 (Saros 125)		1985 Oct 28 (Saros 126)		1996 Sep 27 (Saros 127)		2007 Aug 28 (Saros 128)		2018 Jul 27 (Saros 129)
2029 Jun 26 (Saros 130)		2040 May 26 (Saros 131)		2051 Apr 26 (Saros 132)		2062 Mar 25 (Saros 133)		2073 Feb 22 (Saros 134)
2084 Jan 22 (Saros 135)		2094 Dec 21 (Saros 136)		2105 Nov 21 (Saros 137)		2116 Oct 21 (Saros 138)		2127 Sep 20 (Saros 139)
2138 Aug 20 (Saros 140)		2149 Jul 20 (Saros 141)		2160 Jun 18 (Saros 142)		2171 May 19 (Saros 143)		2182 Apr 18 (Saros 144)
2193 Mar 17 (Saros 145)

Inex series

This eclipse is a part of the long period inex cycle, repeating at alternating nodes, every 358 synodic months (≈ 10,571.95 days, or 29 years minus 20 days). Their appearance and longitude are irregular due to a lack of synchronization with the anomalistic month (period of perigee). However, groupings of 3 inex cycles (≈ 87 years minus 2 months) comes close (≈ 1,151.02 anomalistic months), so eclipses are similar in these groupings.

Series members between 1801 and 2200
1804 Jul 22 (Saros 116)		1833 Jul 02 (Saros 117)		1862 Jun 12 (Saros 118)
1891 May 23 (Saros 119)		1920 May 03 (Saros 120)		1949 Apr 13 (Saros 121)
1978 Mar 24 (Saros 122)		2007 Mar 03 (Saros 123)		2036 Feb 11 (Saros 124)
2065 Jan 22 (Saros 125)		2094 Jan 01 (Saros 126)		2122 Dec 13 (Saros 127)
2151 Nov 24 (Saros 128)		2180 Nov 02 (Saros 129)

Half-Saros cycle

A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros).^[8] This lunar eclipse is related to two total solar eclipses of Solar Saros 127.

April 28, 1911	May 9, 1929

See also

• List of lunar eclipses
• List of 20th-century lunar eclipses