| Annular eclipse | |
 Map | |
| Gamma | −0.2387 |
|---|---|
| Magnitude | 0.9383 |
| Maximum eclipse | |
| Duration | 426 s (7 min 6 s) |
| Coordinates | 36°06′S53°42′W / 36.1°S 53.7°W /-36.1; -53.7 |
| Max. width of band | 236 km (147 mi) |
| Times (UTC) | |
| Greatest eclipse | 15:22:02 |
| References | |
| Saros | 131 (45 of 70) |
| Catalog # (SE5000) | 9325 |
An annularsolar eclipse occurred at the Moon'sascending node of orbit on Tuesday, December 3, 1918,[1] with amagnitude of 0.9383. Asolar eclipse occurs when theMoon passes betweenEarth and theSun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. An annular solar eclipse occurs when the Moon'sapparent diameter is smaller than the Sun's, blocking most of the Sun's light and causing the Sun to look like anannulus (ring). An annular eclipse appears as a partial eclipse over a region of the Earth thousands of kilometres wide. Occurring 4.3 days afterapogee (on November 29, 1918, at 7:10 UTC), the Moon's apparent diameter was smaller.[2]
Annularity was visible fromChile including the capital citySantiago,Argentina including capitalBuenos Aires, southernUruguay including capitalMontevideo, northeastern tip ofSouth West Africa (today'sNamibia) and southwesternPortuguese Angola (today'sAngola).Aconcagua, the highest mountain outside Asia, also lies in the path of annularity. A partial eclipse was visible for parts ofSouth America,Antarctica,Southern Africa, andCentral Africa.
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]
| Event | Time (UTC) |
|---|---|
| First Penumbral External Contact | 1918 December 03 at 12:21:26.8 UTC |
| First Umbral External Contact | 1918 December 03 at 13:26:14.8 UTC |
| First Central Line | 1918 December 03 at 13:28:57.9 UTC |
| First Umbral Internal Contact | 1918 December 03 at 13:31:41.2 UTC |
| First Penumbral Internal Contact | 1918 December 03 at 14:40:20.1 UTC |
| Ecliptic Conjunction | 1918 December 03 at 15:19:13.2 UTC |
| Greatest Eclipse | 1918 December 03 at 15:22:01.5 UTC |
| Greatest Duration | 1918 December 03 at 15:22:11.4 UTC |
| Equatorial Conjunction | 1918 December 03 at 15:23:11.5 UTC |
| Last Penumbral Internal Contact | 1918 December 03 at 16:03:41.9 UTC |
| Last Umbral Internal Contact | 1918 December 03 at 17:12:22.6 UTC |
| Last Central Line | 1918 December 03 at 17:15:03.6 UTC |
| Last Umbral External Contact | 1918 December 03 at 17:17:44.3 UTC |
| Last Penumbral External Contact | 1918 December 03 at 18:22:30.4 UTC |
| Parameter | Value |
|---|---|
| Eclipse Magnitude | 0.93826 |
| Eclipse Obscuration | 0.88034 |
| Gamma | −0.23873 |
| Sun Right Ascension | 16h36m17.1s |
| Sun Declination | -22°03'17.1" |
| Sun Semi-Diameter | 16'13.6" |
| Sun Equatorial Horizontal Parallax | 08.9" |
| Moon Right Ascension | 16h36m14.8s |
| Moon Declination | -22°16'22.8" |
| Moon Semi-Diameter | 15'00.0" |
| Moon Equatorial Horizontal Parallax | 0°55'03.1" |
| ΔT | 20.9 s |
This eclipse is part of aneclipse 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 afortnight.
| December 3 Ascending node (new moon) | December 17 Descending node (full moon) |
|---|---|
|  |
| Annular solar eclipse Solar Saros 131 | Penumbral lunar eclipse Lunar Saros 143 |
This eclipse is a member of asemester series. An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternatingnodes of the Moon's orbit.[4]
The solar eclipses onFebruary 3, 1916 (total),July 30, 1916 (annular),January 23, 1917 (partial), andJuly 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 inPríncipe | 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 | ||||
This eclipse is a part ofSaros series 131, repeating every 18 years, 11 days, and containing 70 events. The series started with a partial solar eclipse on August 1, 1125. It contains total eclipses from March 27, 1522 through May 30, 1612; hybrid eclipses from June 10, 1630 through July 24, 1702; and annular eclipses from August 4, 1720 through June 18, 2243. The series ends at member 70 as a partial eclipse on September 2, 2369. Its eclipses are tabulated in three columns; every third eclipse in the same column is oneexeligmos apart, so they all cast shadows over approximately the same parts of the Earth.
The longest duration of totality was produced by member 28 at 58 seconds on May 30, 1612, and the longest duration of annularity was produced by member 50 at 7 minutes, 54 seconds onJanuary 26, 2009. All eclipses in this series occur at the Moon’sascending node of orbit.[5]
| Series members 39–60 occur between 1801 and 2200: | ||
|---|---|---|
| 39 | 40 | 41 |
 September 28, 1810 |  October 9, 1828 |  October 20, 1846 |
| 42 | 43 | 44 |
 October 30, 1864 |  November 10, 1882 |  November 22, 1900 |
| 45 | 46 | 47 |
December 3, 1918 |  December 13, 1936 |  December 25, 1954 |
| 48 | 49 | 50 |
 January 4, 1973 |  January 15, 1991 |  January 26, 2009 |
| 51 | 52 | 53 |
 February 6, 2027 |  February 16, 2045 |  February 28, 2063 |
| 54 | 55 | 56 |
 March 10, 2081 |  March 21, 2099 |  April 2, 2117 |
| 57 | 58 | 59 |
 April 13, 2135 |  April 23, 2153 |  May 5, 2171 |
| 60 | ||
 May 15, 2189 | ||
Themetonic 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 2, 1880 and July 9, 1964 | ||||
|---|---|---|---|---|
| December 2–3 | September 20–21 | July 9–10 | April 26–28 | February 13–14 |
| 111 | 113 | 115 | 117 | 119 |
 December 2, 1880 |  July 9, 1888 |  April 26, 1892 |  February 13, 1896 | |
| 121 | 123 | 125 | 127 | 129 |
 December 3, 1899 |  September 21, 1903 |  July 10, 1907 |  April 28, 1911 |  February 14, 1915 |
| 131 | 133 | 135 | 137 | 139 |
December 3, 1918 |  September 21, 1922 |  July 9, 1926 |  April 28, 1930 |  February 14, 1934 |
| 141 | 143 | 145 | 147 | 149 |
 December 2, 1937 |  September 21, 1941 |  July 9, 1945 |  April 28, 1949 |  February 14, 1953 |
| 151 | 153 | 155 | ||
 December 2, 1956 |  September 20, 1960 |  July 9, 1964 | ||
This eclipse is a part of atritos cycle, repeating at alternating nodes every 135synodic months (≈ 3986.63 days, or 11 years minus 1 month). Their appearance and longitude are irregular due to a lack of synchronization with theanomalistic 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 9, 1809 (Saros 121) |  September 7, 1820 (Saros 122) |  August 7, 1831 (Saros 123) |  July 8, 1842 (Saros 124) |  June 6, 1853 (Saros 125) |
 May 6, 1864 (Saros 126) |  April 6, 1875 (Saros 127) |  March 5, 1886 (Saros 128) |  February 1, 1897 (Saros 129) |  January 3, 1908 (Saros 130) |
December 3, 1918 (Saros 131) |  November 1, 1929 (Saros 132) |  October 1, 1940 (Saros 133) |  September 1, 1951 (Saros 134) |  July 31, 1962 (Saros 135) |
 June 30, 1973 (Saros 136) |  May 30, 1984 (Saros 137) |  April 29, 1995 (Saros 138) |  March 29, 2006 (Saros 139) |  February 26, 2017 (Saros 140) |
 January 26, 2028 (Saros 141) |  December 26, 2038 (Saros 142) |  November 25, 2049 (Saros 143) |  October 24, 2060 (Saros 144) |  September 23, 2071 (Saros 145) |
 August 24, 2082 (Saros 146) |  July 23, 2093 (Saros 147) |  June 22, 2104 (Saros 148) |  May 24, 2115 (Saros 149) |  April 22, 2126 (Saros 150) |
 March 21, 2137 (Saros 151) |  February 19, 2148 (Saros 152) |  January 19, 2159 (Saros 153) |  December 18, 2169 (Saros 154) |  November 17, 2180 (Saros 155) |
 October 18, 2191 (Saros 156) | ||||
This eclipse is a part of the long periodinex cycle, repeating at alternating nodes, every 358synodic months (≈ 10,571.95 days, or 29 years minus 20 days). Their appearance and longitude are irregular due to a lack of synchronization with theanomalistic 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 | ||
|---|---|---|
 February 21, 1803 (Saros 127) |  February 1, 1832 (Saros 128) |  January 11, 1861 (Saros 129) |
 December 22, 1889 (Saros 130) | December 3, 1918 (Saros 131) |  November 12, 1947 (Saros 132) |
 October 23, 1976 (Saros 133) |  October 3, 2005 (Saros 134) |  September 12, 2034 (Saros 135) |
 August 24, 2063 (Saros 136) |  August 3, 2092 (Saros 137) |  July 14, 2121 (Saros 138) |
 June 25, 2150 (Saros 139) |  June 5, 2179 (Saros 140) | |
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