Solar eclipse of June 20, 1974

Solar eclipse of June 20, 1974
Map
Type of eclipse
NatureTotal
Gamma−0.8239
Magnitude1.0592
Maximum eclipse
Duration309 s (5 min 9 s)
Coordinates32°06′S 103°42′E / 32.1°S 103.7°E / -32.1; 103.7
Max. width of band344 km (214 mi)
Times (UTC)
Greatest eclipse4:48:04
References
Saros146 (25 of 76)
Catalog # (SE5000)9452

A total solar eclipse occurred at the Moon's descending node of orbit on Thursday, June 20, 1974,[1] with a magnitude of 1.0592. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the view of the Sun for a viewer on Earth. A total solar eclipse occurs when the Moon's apparent diameter is larger than the Sun's, blocking all direct sunlight, turning day into darkness. Totality occurs in a narrow path across Earth's surface, with the partial solar eclipse visible over a surrounding region thousands of kilometres wide. Occurring about 1.4 days before perigee (on June 21, 1974, at 14:50 UTC), the Moon's apparent diameter was larger.[2]

The path of totality passed over the Indian Ocean, Amsterdam Island, and Western Australia. A partial eclipse was visible for parts of Madagascar, Indonesia, Australia, and the southwestern coast of South Island, New Zealand.[3]

Eclipse details

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Shown below are two tables displaying details about this particular solar eclipse. The first table outlines times at which the moon's penumbra or umbra attains the specific parameter, and the second table describes various other parameters pertaining to this eclipse.[4]

June 20, 1974 Solar Eclipse Times
Event Time (UTC)
First Penumbral External Contact 1974 June 20 at 02:33:32.2 UTC
First Umbral External Contact 1974 June 20 at 03:47:06.1 UTC
First Central Line 1974 June 20 at 03:49:24.2 UTC
First Umbral Internal Contact 1974 June 20 at 03:51:46.3 UTC
Greatest Duration 1974 June 20 at 04:47:57.2 UTC
Greatest Eclipse 1974 June 20 at 04:48:04.4 UTC
Equatorial Conjunction 1974 June 20 at 04:55:25.3 UTC
Ecliptic Conjunction 1974 June 20 at 04:56:24.3 UTC
Last Umbral Internal Contact 1974 June 20 at 05:44:15.8 UTC
Last Central Line 1974 June 20 at 05:46:39.4 UTC
Last Umbral External Contact 1974 June 20 at 05:48:59.2 UTC
Last Penumbral External Contact 1974 June 20 at 07:02:30.3 UTC
June 20, 1974 Solar Eclipse Parameters
Parameter Value
Eclipse Magnitude 1.05919
Eclipse Obscuration 1.12189
Gamma −0.82388
Sun Right Ascension 05h53m26.3s
Sun Declination +23°26'00.3"
Sun Semi-Diameter 15'44.3"
Sun Equatorial Horizontal Parallax 08.7"
Moon Right Ascension 05h53m07.9s
Moon Declination +22°36'22.0"
Moon Semi-Diameter 16'30.9"
Moon Equatorial Horizontal Parallax 1°00'36.8"
ΔT 44.9 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.

Eclipse season of June 1974
June 4
Ascending node (full moon)
 June 20
Descending node (new moon)
Partial lunar eclipse
Lunar Saros 120		 Total solar eclipse
Solar Saros 146
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Eclipses in 1974

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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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Solar Saros 146

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Inex

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Triad

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Solar eclipses of 1971–1974

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This eclipse is a member of a semester series. An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternating nodes of the Moon's orbit.[5]

The partial solar eclipses on February 25, 1971 and August 20, 1971 occur in the previous lunar year eclipse set.

Solar eclipse series sets from 1971 to 1974
Descending node   Ascending node
Saros Map Gamma Saros Map Gamma
116 July 22, 1971

Partial 		1.513 121 January 16, 1972

Annular 		−0.9365
126 July 10, 1972

Total 		0.6872 131 January 4, 1973

Annular 		−0.2644
136 June 30, 1973

Total 		−0.0785 141 December 24, 1973

Annular 		0.4171
146 June 20, 1974

Total 		−0.8239 151 December 13, 1974

Partial 		1.0797

Saros 146

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This eclipse is a part of Saros series 146, repeating every 18 years, 11 days, and containing 76 events. The series started with a partial solar eclipse on September 19, 1541. It contains total eclipses from May 29, 1938 through October 7, 2154; hybrid eclipses from October 17, 2172 through November 20, 2226; and annular eclipses from November 30, 2244 through August 10, 2659. The series ends at member 76 as a partial eclipse on December 29, 2893. Its 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.

The longest duration of totality was produced by member 26 at 5 minutes, 21 seconds on June 30, 1992, and the longest duration of annularity will be produced by member 63 at 3 minutes, 30 seconds on August 10, 2659. All eclipses in this series occur at the Moon’s descending node of orbit.[6]

Series members 16–37 occur between 1801 and 2200:
16 17 18

March 13, 1812
March 24, 1830
April 3, 1848
19 20 21

April 15, 1866
April 25, 1884
May 7, 1902
22 23 24

May 18, 1920
May 29, 1938
June 8, 1956
25 26 27

June 20, 1974
June 30, 1992
July 11, 2010
28 29 30

July 22, 2028
August 2, 2046
August 12, 2064
31 32 33

August 24, 2082
September 4, 2100
September 15, 2118
34 35 36

September 26, 2136
October 7, 2154
October 17, 2172
37

October 29, 2190

Metonic series

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The metonic series repeats eclipses every 19 years (6939.69 days), lasting about 5 cycles. Eclipses occur in nearly the same calendar date. In addition, the octon subseries repeats 1/5 of that or every 3.8 years (1387.94 days). All eclipses in this table occur at the Moon's descending node.

22 eclipse events between April 8, 1902 and August 31, 1989
April 7–8 January 24–25 November 12 August 31–September 1 June 19–20
108 110 112 114 116

April 8, 1902
August 31, 1913
June 19, 1917
118 120 122 124 126

April 8, 1921
January 24, 1925
November 12, 1928
August 31, 1932
June 19, 1936
128 130 132 134 136

April 7, 1940
January 25, 1944
November 12, 1947
September 1, 1951
June 20, 1955
138 140 142 144 146

April 8, 1959
January 25, 1963
November 12, 1966
August 31, 1970
June 20, 1974
148 150 152 154

April 7, 1978
January 25, 1982
November 12, 1985
August 31, 1989

Tritos series

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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.

The partial solar eclipses on December 7, 2170 (part of Saros 164) and November 7, 2181 (part of Saros 165) are also a part of this series but are not included in the table below.

Series members between 1801 and 2105

September 28, 1810
(Saros 131)
August 27, 1821
(Saros 132)
July 27, 1832
(Saros 133)
June 27, 1843
(Saros 134)
May 26, 1854
(Saros 135)

April 25, 1865
(Saros 136)
March 25, 1876
(Saros 137)
February 22, 1887
(Saros 138)
January 22, 1898
(Saros 139)
December 23, 1908
(Saros 140)

November 22, 1919
(Saros 141)
October 21, 1930
(Saros 142)
September 21, 1941
(Saros 143)
August 20, 1952
(Saros 144)
July 20, 1963
(Saros 145)

June 20, 1974
(Saros 146)
May 19, 1985
(Saros 147)
April 17, 1996
(Saros 148)
March 19, 2007
(Saros 149)
February 15, 2018
(Saros 150)

January 14, 2029
(Saros 151)
December 15, 2039
(Saros 152)
November 14, 2050
(Saros 153)
October 13, 2061
(Saros 154)
September 12, 2072
(Saros 155)

August 13, 2083
(Saros 156)
July 12, 2094
(Saros 157)
June 12, 2105
(Saros 158)

Inex series

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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

September 28, 1829
(Saros 141)
September 7, 1858
(Saros 142)
August 19, 1887
(Saros 143)

July 30, 1916
(Saros 144)
July 9, 1945
(Saros 145)
June 20, 1974
(Saros 146)

May 31, 2003
(Saros 147)
May 9, 2032
(Saros 148)
April 20, 2061
(Saros 149)

March 31, 2090
(Saros 150)
March 11, 2119
(Saros 151)
February 19, 2148
(Saros 152)

January 29, 2177
(Saros 153)

References

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  1. ^ "June 20, 1974 Total Solar Eclipse". timeanddate. Retrieved 8 August 2024.
  2. ^ "Moon Distances for London, United Kingdom, England". timeanddate. Retrieved 8 August 2024.
  3. ^ Duncombe, Julena S. (June 15, 1973). "Total Solar Eclipse of 20 June 1974". United States Naval Observatory Circular. 144: 2. Bibcode:1973USNOC.144.....D.
  4. ^ "Total Solar Eclipse of 1974 Jun 20". EclipseWise.com. Retrieved 8 August 2024.
  5. ^ 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.
  6. ^ "NASA - Catalog of Solar Eclipses of Saros 146". eclipse.gsfc.nasa.gov.
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