July 1972 lunar eclipse

A partial lunar eclipse occurred at the Moon’s ascending node of orbit on Wednesday, July 26, 1972,^[1] with an umbral magnitude of 0.5427. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A partial lunar eclipse occurs when one part of the Moon is in the Earth's umbra, while the other part is in the Earth's penumbra. 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. Occurring about 6.4 days after apogee (on July 19, 1972, at 21:20 UTC), the Moon's apparent diameter was smaller.^[2]

July 1972 lunar eclipse

Partial eclipse
The Moon's hourly motion shown right to left
Date	July 26, 1972
Gamma	0.7117
Magnitude	0.5427
Saros cycle	138 (27 of 83)
Partiality	160 minutes, 8 seconds
Penumbral	312 minutes, 27 seconds
Contacts (UTC) P1 4:39:26 U1 5:55:39 Greatest 7:15:39 U4 8:35:47 P4 9:51:52
← January 1972 January 1973 →

Visibility

The eclipse was completely visible over much of North and South America and Antarctica, seen rising over Australia, northwestern North America]], and the central Pacific Ocean and setting over northeastern North America, west Africa, and the Atlantic Ocean.^[3]

Eclipse details

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

July 26, 1972 Lunar Eclipse Parameters

Parameter	Value
Penumbral Magnitude	1.56180
Umbral Magnitude	0.54271
Gamma	0.71167
Sun Right Ascension	08h22m46.8s
Sun Declination	+19°24'04.5"
Sun Semi-Diameter	15'44.9"
Sun Equatorial Horizontal Parallax	08.7"
Moon Right Ascension	20h21m51.2s
Moon Declination	-18°45'55.3"
Moon Semi-Diameter	15'27.2"
Moon Equatorial Horizontal Parallax	0°56'42.9"
ΔT	42.8 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 July 1972

July 10 Descending node (new moon)	July 26 Ascending node (full moon)
Total solar eclipse Solar Saros 126	Partial lunar eclipse Lunar Saros 138

Related eclipses

Eclipses in 1972

• An annular solar eclipse on January 16.
• A total lunar eclipse on January 30.
• A total solar eclipse on July 10.
• A partial lunar eclipse on July 26.

Metonic

• Preceded by: Lunar eclipse of October 6, 1968
• Followed by: Lunar eclipse of May 13, 1976

Tzolkinex

• Preceded by: Lunar eclipse of June 14, 1965
• Followed by: Lunar eclipse of September 6, 1979

Half-Saros

• Preceded by: Solar eclipse of July 20, 1963
• Followed by: Solar eclipse of July 31, 1981

Tritos

• Preceded by: Lunar eclipse of August 26, 1961
• Followed by: Lunar eclipse of June 25, 1983

Lunar Saros 138

• Preceded by: Lunar eclipse of July 16, 1954
• Followed by: Lunar eclipse of August 6, 1990

Inex

• Preceded by: Lunar eclipse of August 15, 1943
• Followed by: Lunar eclipse of July 5, 2001

Triad

• Preceded by: Lunar eclipse of September 24, 1885
• Followed by: Lunar eclipse of May 27, 2059

Lunar eclipses of 1969–1973

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 eclipses on April 2, 1969 and September 25, 1969 occur in the previous lunar year eclipse set, and the lunar eclipses on June 15, 1973 (penumbral) and December 10, 1973 (partial) occur in the next lunar year eclipse set.

Lunar eclipse series sets from 1969 to 1973
Ascending node					Descending node
Saros	Date Viewing	Type Chart	Gamma		Saros	Date Viewing	Type Chart	Gamma
108	1969 Aug 27	Penumbral	−1.5407		113	1970 Feb 21	Partial	0.9620
118	1970 Aug 17	Partial	−0.8053		123	1971 Feb 10	Total	0.2741
128	1971 Aug 06	Total	−0.0794		133	1972 Jan 30	Total	−0.4273
138	1972 Jul 26	Partial	0.7117		143	1973 Jan 18	Penumbral	−1.0845
148	1973 Jul 15	Penumbral	1.5178

Saros 138

This eclipse is a part of Saros series 138, repeating every 18 years, 11 days, and containing 82 events. The series started with a penumbral lunar eclipse on October 15, 1521. It contains partial eclipses from June 24, 1918 through August 28, 2026; total eclipses from September 7, 2044 through June 8, 2495; and a second set of partial eclipses from June 19, 2513 through August 13, 2603. The series ends at member 82 as a penumbral eclipse on March 30, 2982.

The longest duration of totality will be produced by member 48 at 105 minutes, 24 seconds on March 24, 2369. All eclipses in this series occur at the Moon’s ascending node of orbit.^[6]

Greatest	First
The greatest eclipse of the series will occur on 2369 Mar 24, lasting 105 minutes, 24 seconds.[7]	Penumbral	Partial	Total	Central
	1521 Oct 15	1918 Jun 24	2044 Sep 07	2116 Oct 21
	Last
	Central	Total	Partial	Penumbral
	2441 May 06	2495 Jun 08	2603 Aug 13	2982 Mar 30

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 17–38 occur between 1801 and 2200:
17		18		19
1810 Apr 19		1828 Apr 29		1846 May 11
20		21		22
1864 May 21		1882 Jun 01		1900 Jun 13
23		24		25
1918 Jun 24		1936 Jul 04		1954 Jul 16
26		27		28
1972 Jul 26		1990 Aug 06		2008 Aug 16
29		30		31
2026 Aug 28		2044 Sep 07		2062 Sep 18
32		33		34
2080 Sep 29		2098 Oct 10		2116 Oct 21
35		36		37
2134 Nov 02		2152 Nov 12		2170 Nov 23
38
2188 Dec 04

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
1808 Nov 03 (Saros 123)		1819 Oct 03 (Saros 124)		1830 Sep 02 (Saros 125)		1841 Aug 02 (Saros 126)		1852 Jul 01 (Saros 127)
1863 Jun 01 (Saros 128)		1874 May 01 (Saros 129)		1885 Mar 30 (Saros 130)		1896 Feb 28 (Saros 131)		1907 Jan 29 (Saros 132)
1917 Dec 28 (Saros 133)		1928 Nov 27 (Saros 134)		1939 Oct 28 (Saros 135)		1950 Sep 26 (Saros 136)		1961 Aug 26 (Saros 137)
1972 Jul 26 (Saros 138)		1983 Jun 25 (Saros 139)		1994 May 25 (Saros 140)		2005 Apr 24 (Saros 141)		2016 Mar 23 (Saros 142)
2027 Feb 20 (Saros 143)		2038 Jan 21 (Saros 144)		2048 Dec 20 (Saros 145)		2059 Nov 19 (Saros 146)		2070 Oct 19 (Saros 147)
2081 Sep 18 (Saros 148)		2092 Aug 17 (Saros 149)		2103 Jul 19 (Saros 150)		2114 Jun 18 (Saros 151)		2125 May 17 (Saros 152)
2136 Apr 16 (Saros 153)						2169 Jan 13 (Saros 156)
2190 Nov 12 (Saros 158)

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
1827 Nov 03 (Saros 133)		1856 Oct 13 (Saros 134)		1885 Sep 24 (Saros 135)
1914 Sep 04 (Saros 136)		1943 Aug 15 (Saros 137)		1972 Jul 26 (Saros 138)
2001 Jul 05 (Saros 139)		2030 Jun 15 (Saros 140)		2059 May 27 (Saros 141)
2088 May 05 (Saros 142)		2117 Apr 16 (Saros 143)		2146 Mar 28 (Saros 144)
2175 Mar 07 (Saros 145)

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 145.

July 20, 1963	July 31, 1981

See also

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