# Solar eclipse of December 14, 1917

An annular solar eclipse occurred at the Moon's ascending node of orbit on Friday, December 14, 1917, 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.
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

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.
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

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 |

## Related eclipses
### Eclipses in 1917

* A total lunar eclipse on January 8.
* A partial solar eclipse on January 23.
* A partial solar eclipse on June 19.
* A total lunar eclipse on July 4.
* A partial solar eclipse on July 19.
* An annular solar eclipse on December 14.
* A total lunar eclipse on December 28.

### Metonic

* Preceded by: Solar eclipse of February 25, 1914
* Followed by: Solar eclipse of October 1, 1921

### Tzolkinex

* Preceded by: Solar eclipse of November 2, 1910
* Followed by: Solar eclipse of January 24, 1925

### Half-Saros

* Preceded by: Lunar eclipse of December 7, 1908
* Followed by: Lunar eclipse of December 19, 1926

### Tritos

* Preceded by: Solar eclipse of January 14, 1907
* Followed by: Solar eclipse of November 12, 1928

### Solar Saros 121

* Preceded by: Solar eclipse of December 3, 1899
* Followed by: Solar eclipse of December 25, 1935

### Inex

* Preceded by: Solar eclipse of January 1, 1889
* Followed by: Solar eclipse of November 23, 1946

### Triad

* Preceded by: Solar eclipse of February 12, 1831
* Followed by: Solar eclipse of October 14, 2004

### Solar eclipses of 1916–1920

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.
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 | Ascending node | Ascending node | Descending node | Descending 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

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.
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

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

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

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) | |