Solar eclipse of December 14, 1917

An annular solar eclipse occurred at the Moon's ascending node of orbit on Friday, December 14, 1917,[1] with a magnitude of 0.9791. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. An annular solar eclipse occurs when the Moon's apparent diameter is smaller than the Sun's, blocking most of the Sun's light and causing the Sun to look like an annulus (ring). An annular eclipse appears as a partial eclipse over a region of the Earth thousands of kilometres wide. Occurring 4.6 days before apogee (on December 18, 1917, at 22:10 UTC), the Moon's apparent diameter was smaller.[2]

Solar eclipse of December 14, 1917
Map
Type of eclipse
NatureAnnular
Gamma−0.9157
Magnitude0.9791
Maximum eclipse
Duration77 s (1 min 17 s)
Coordinates88°00′S 124°48′E / 88°S 124.8°E / -88; 124.8
Max. width of band189 km (117 mi)
Times (UTC)
Greatest eclipse9:27:20
References
Saros121 (55 of 71)
Catalog # (SE5000)9323

This was the last of four solar eclipses in 1917, with the others occurring on January 23, June 19 and July 19.

The path of annularity crossed Antarctica. A partial eclipse was visible for parts of Antarctica, southern South America, and Australia. This annular eclipse is notable in that the path of annularity passed over the South Pole.

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.[3]

December 14, 1917 Solar Eclipse Times
Event Time (UTC)
First Penumbral External Contact 1917 December 14 at 07:09:48.7 UTC
First Umbral External Contact 1917 December 14 at 08:41:49.9 UTC
First Central Line 1917 December 14 at 08:43:56.6 UTC
Greatest Duration 1917 December 14 at 08:43:56.6 UTC
First Umbral Internal Contact 1917 December 14 at 08:46:08.6 UTC
Ecliptic Conjunction 1917 December 14 at 09:17:22.8 UTC
Equatorial Conjunction 1917 December 14 at 09:23:35.1 UTC
Greatest Eclipse 1917 December 14 at 09:27:19.7 UTC
Last Umbral Internal Contact 1917 December 14 at 10:08:36.2 UTC
Last Central Line 1917 December 14 at 10:10:45.3 UTC
Last Umbral External Contact 1917 December 14 at 10:12:49.1 UTC
Last Penumbral External Contact 1917 December 14 at 11:44:46.7 UTC
December 14, 1917 Solar Eclipse Parameters
Parameter Value
Eclipse Magnitude 0.97913
Eclipse Obscuration 0.95870
Gamma –0.91566
Sun Right Ascension 17h24m28.1s
Sun Declination -23°11'55.0"
Sun Semi-Diameter 16'15.0"
Sun Equatorial Horizontal Parallax 08.9"
Moon Right Ascension 17h24m36.7s
Moon Declination -24°04'53.4"
Moon Semi-Diameter 15'48.9"
Moon Equatorial Horizontal Parallax 0°58'02.6"
ΔT 20.2 s

Eclipse season

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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 December 1917
December 14
Ascending node (new moon)
December 28
Descending node (full moon)
   
Annular solar eclipse
Solar Saros 121
Total lunar eclipse
Lunar Saros 133
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Eclipses in 1917

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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 121

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Inex

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Triad

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Solar eclipses of 1916–1920

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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.[4]

The solar eclipses on February 3, 1916 (total), July 30, 1916 (annular), January 23, 1917 (partial), and July 19, 1917 (partial) occur in the previous lunar year eclipse set.

Solar eclipse series sets from 1916 to 1920
Ascending node   Descending node
Saros Map Gamma Saros Map Gamma
111 December 24, 1916
 
Partial
−1.5321 116 June 19, 1917
 
Partial
1.2857
121 December 14, 1917
 
Annular
−0.9157 126 June 8, 1918
 
Total
0.4658
131 December 3, 1918
 
Annular
−0.2387 136
 
Totality in Príncipe
May 29, 1919
 
Total
−0.2955
141 November 22, 1919
 
Annular
0.4549 146 May 18, 1920
 
Partial
−1.0239
151 November 10, 1920
 
Partial
1.1287

Saros 121

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This eclipse is a part of Saros series 121, repeating every 18 years, 11 days, and containing 71 events. The series started with a partial solar eclipse on April 25, 944 AD. It contains total eclipses from July 10, 1070 through October 9, 1809; hybrid eclipses on October 20, 1827 and October 30, 1845; and annular eclipses from November 11, 1863 through February 28, 2044. The series ends at member 71 as a partial eclipse on June 7, 2206. 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 39 at 6 minutes, 20 seconds on June 21, 1629, and the longest duration of annularity will be produced by member 62 at 2 minutes, 27 seconds on February 28, 2044. All eclipses in this series occur at the Moon’s ascending node of orbit.[5]

Series members 49–70 occur between 1801 and 2200:
49 50 51
 
October 9, 1809
 
October 20, 1827
 
October 30, 1845
52 53 54
 
November 11, 1863
 
November 21, 1881
 
December 3, 1899
55 56 57
 
December 14, 1917
 
December 25, 1935
 
January 5, 1954
58 59 60
 
January 16, 1972
 
January 26, 1990
 
February 7, 2008
61 62 63
 
February 17, 2026
 
February 28, 2044
 
March 11, 2062
64 65 66
 
March 21, 2080
 
April 1, 2098
 
April 13, 2116
67 68 69
 
April 24, 2134
 
May 4, 2152
 
May 16, 2170
70
 
May 26, 2188

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 ascending node.

22 eclipse events between December 13, 1898 and July 20, 1982
December 13–14 October 1–2 July 20–21 May 9 February 24–25
111 113 115 117 119
 
December 13, 1898
 
July 21, 1906
 
May 9, 1910
 
February 25, 1914
121 123 125 127 129
 
December 14, 1917
 
October 1, 1921
 
July 20, 1925
 
May 9, 1929
 
February 24, 1933
131 133 135 137 139
 
December 13, 1936
 
October 1, 1940
 
July 20, 1944
 
May 9, 1948
 
February 25, 1952
141 143 145 147 149
 
December 14, 1955
 
October 2, 1959
 
July 20, 1963
 
May 9, 1967
 
February 25, 1971
151 153 155
 
December 13, 1974
 
October 2, 1978
 
July 20, 1982

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.

Series members between 1801 and 2200
 
October 19, 1808
(Saros 111)
 
September 19, 1819
(Saros 112)
 
August 18, 1830
(Saros 113)
 
July 18, 1841
(Saros 114)
 
June 17, 1852
(Saros 115)
 
May 17, 1863
(Saros 116)
 
April 16, 1874
(Saros 117)
 
March 16, 1885
(Saros 118)
 
February 13, 1896
(Saros 119)
 
January 14, 1907
(Saros 120)
 
December 14, 1917
(Saros 121)
 
November 12, 1928
(Saros 122)
 
October 12, 1939
(Saros 123)
 
September 12, 1950
(Saros 124)
 
August 11, 1961
(Saros 125)
 
July 10, 1972
(Saros 126)
 
June 11, 1983
(Saros 127)
 
May 10, 1994
(Saros 128)
 
April 8, 2005
(Saros 129)
 
March 9, 2016
(Saros 130)
 
February 6, 2027
(Saros 131)
 
January 5, 2038
(Saros 132)
 
December 5, 2048
(Saros 133)
 
November 5, 2059
(Saros 134)
 
October 4, 2070
(Saros 135)
 
September 3, 2081
(Saros 136)
 
August 3, 2092
(Saros 137)
 
July 4, 2103
(Saros 138)
 
June 3, 2114
(Saros 139)
 
May 3, 2125
(Saros 140)
 
April 1, 2136
(Saros 141)
 
March 2, 2147
(Saros 142)
 
January 30, 2158
(Saros 143)
 
December 29, 2168
(Saros 144)
 
November 28, 2179
(Saros 145)
 
October 29, 2190
(Saros 146)

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
 
March 4, 1802
(Saros 117)
 
February 12, 1831
(Saros 118)
 
January 23, 1860
(Saros 119)
 
January 1, 1889
(Saros 120)
 
December 14, 1917
(Saros 121)
 
November 23, 1946
(Saros 122)
 
November 3, 1975
(Saros 123)
 
October 14, 2004
(Saros 124)
 
September 23, 2033
(Saros 125)
 
September 3, 2062
(Saros 126)
 
August 15, 2091
(Saros 127)
 
July 25, 2120
(Saros 128)
 
July 5, 2149
(Saros 129)
 
June 16, 2178
(Saros 130)

Notes

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  1. ^ "December 14, 1917 Annular Solar Eclipse". timeanddate. Retrieved 1 August 2024.
  2. ^ "Moon Distances for London, United Kingdom, England". timeanddate. Retrieved 1 August 2024.
  3. ^ "Annular Solar Eclipse of 1917 Dec 14". EclipseWise.com. Retrieved 1 August 2024.
  4. ^ 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.
  5. ^ "NASA - Catalog of Solar Eclipses of Saros 121". eclipse.gsfc.nasa.gov.

References

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