| Total eclipse | |
 Map | |
| Gamma | −0.9383 |
|---|---|
| Magnitude | 1.0293 |
| Maximum eclipse | |
| Duration | 112 s (1 min 52 s) |
| Coordinates | 66°06′S56°06′W / 66.1°S 56.1°W /-66.1; -56.1 |
| Max. width of band | 291 km (181 mi) |
| Times (UTC) | |
| Greatest eclipse | 12:35:58 |
| References | |
| Saros | 123 (48 of 70) |
| Catalog # (SE5000) | 9331 |
A totalsolar eclipse occurred at the Moon'sascending node of orbit on Saturday, October 1, 1921,[1] with amagnitude of 1.0293. Asolar eclipse occurs when theMoon passes betweenEarth and theSun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. A total solar eclipse occurs when the Moon'sapparent 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 1.9 days afterperigee (on September 29, 1921, at 14:50 UTC), the Moon's apparent diameter was larger.[2]
Totality was visible from parts ofAntarctica. A partial eclipse was visible for parts ofSouth America andAntarctica.
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 | 1921 October 1 at 10:27:26.7 UTC |
| First Umbral External Contact | 1921 October 1 at 11:58:17.2 UTC |
| First Central Line | 1921 October 1 at 12:00:11.9 UTC |
| First Umbral Internal Contact | 1921 October 1 at 12:02:12.3 UTC |
| Ecliptic Conjunction | 1921 October 1 at 12:26:22.9 UTC |
| Greatest Duration | 1921 October 1 at 12:35:07.2 UTC |
| Greatest Eclipse | 1921 October 1 at 12:35:58.1 UTC |
| Equatorial Conjunction | 1921 October 1 at 13:07:31.9 UTC |
| Last Umbral Internal Contact | 1921 October 1 at 13:09:22.8 UTC |
| Last Central Line | 1921 October 1 at 13:11:21.2 UTC |
| Last Umbral External Contact | 1921 October 1 at 13:13:14.0 UTC |
| Last Penumbral External Contact | 1921 October 1 at 14:44:18.5 UTC |
| Parameter | Value |
|---|---|
| Eclipse Magnitude | 1.02931 |
| Eclipse Obscuration | 1.05948 |
| Gamma | −0.93833 |
| Sun Right Ascension | 12h28m35.7s |
| Sun Declination | -03°05'21.9" |
| Sun Semi-Diameter | 15'58.8" |
| Sun Equatorial Horizontal Parallax | 08.8" |
| Moon Right Ascension | 12h27m27.1s |
| Moon Declination | -03°58'54.5" |
| Moon Semi-Diameter | 16'21.8" |
| Moon Equatorial Horizontal Parallax | 1°00'03.1" |
| ΔT | 22.4 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.
| October 1 Ascending node (new moon) | October 16 Descending node (full moon) |
|---|---|
|  |
| Total solar eclipse Solar Saros 123 | Partial lunar eclipse Lunar Saros 135 |
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 partial solar eclipse onJuly 31, 1924 occurs in the next lunar year eclipse set.
| Solar eclipse series sets from 1921 to 1924 | ||||||
|---|---|---|---|---|---|---|
| Descending node | Ascending node | |||||
| Saros | Map | Gamma | Saros | Map | Gamma | |
| 118 | April 8, 1921 Annular | 0.8869 | 123 | October 1, 1921 Total | −0.9383 | |
| 128 | March 28, 1922 Annular | 0.1711 | 133 | September 21, 1922 Total | −0.213 | |
| 138 | March 17, 1923 Annular | −0.5438 | 143 | September 10, 1923 Total | 0.5149 | |
| 148 | March 5, 1924 Partial | −1.2232 | 153 | August 30, 1924 Partial | 1.3123 | |
This eclipse is a part ofSaros series 123, repeating every 18 years, 11 days, and containing 70 events. The series started with a partial solar eclipse on April 29, 1074. It contains annular eclipses from July 2, 1182 through April 19, 1651; hybrid eclipses from April 30, 1669 through May 22, 1705; and total eclipses from June 3, 1723 throughOctober 23, 1957. The series ends at member 70 as a partial eclipse on May 31, 2318. 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 annularity was produced by member 19 at 8 minutes, 7 seconds on November 9, 1398, and the longest duration of totality was produced by member 42 at 3 minutes, 27 seconds on July 27, 1813. All eclipses in this series occur at the Moon’sascending node of orbit.[5]
| Series members 42–63 occur between 1801 and 2200: | ||
|---|---|---|
| 42 | 43 | 44 |
 July 27, 1813 |  August 7, 1831 |  August 18, 1849 |
| 45 | 46 | 47 |
 August 29, 1867 |  September 8, 1885 |  September 21, 1903 |
| 48 | 49 | 50 |
October 1, 1921 |  October 12, 1939 |  October 23, 1957 |
| 51 | 52 | 53 |
 November 3, 1975 |  November 13, 1993 |  November 25, 2011 |
| 54 | 55 | 56 |
 December 5, 2029 |  December 16, 2047 |  December 27, 2065 |
| 57 | 58 | 59 |
 January 7, 2084 |  January 19, 2102 |  January 30, 2120 |
| 60 | 61 | 62 |
 February 9, 2138 |  February 21, 2156 |  March 3, 2174 |
| 63 | ||
 March 13, 2192 | ||
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 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 | ||
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 | ||||
|---|---|---|---|---|
 September 8, 1801 (Saros 112) |  August 7, 1812 (Saros 113) |  July 8, 1823 (Saros 114) |  June 7, 1834 (Saros 115) |  May 6, 1845 (Saros 116) |
 April 5, 1856 (Saros 117) |  March 6, 1867 (Saros 118) |  February 2, 1878 (Saros 119) |  January 1, 1889 (Saros 120) |  December 3, 1899 (Saros 121) |
 November 2, 1910 (Saros 122) | October 1, 1921 (Saros 123) |  August 31, 1932 (Saros 124) |  August 1, 1943 (Saros 125) |  June 30, 1954 (Saros 126) |
 May 30, 1965 (Saros 127) |  April 29, 1976 (Saros 128) |  March 29, 1987 (Saros 129) |  February 26, 1998 (Saros 130) |  January 26, 2009 (Saros 131) |
 December 26, 2019 (Saros 132) |  November 25, 2030 (Saros 133) |  October 25, 2041 (Saros 134) |  September 22, 2052 (Saros 135) |  August 24, 2063 (Saros 136) |
 July 24, 2074 (Saros 137) |  June 22, 2085 (Saros 138) |  May 22, 2096 (Saros 139) |  April 23, 2107 (Saros 140) |  March 22, 2118 (Saros 141) |
 February 18, 2129 (Saros 142) |  January 20, 2140 (Saros 143) |  December 19, 2150 (Saros 144) |  November 17, 2161 (Saros 145) |  October 17, 2172 (Saros 146) |
 September 16, 2183 (Saros 147) |  August 16, 2194 (Saros 148) | |||
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 | ||
|---|---|---|
 December 21, 1805 (Saros 119) |  November 30, 1834 (Saros 120) |  November 11, 1863 (Saros 121) |
 October 20, 1892 (Saros 122) | October 1, 1921 (Saros 123) |  September 12, 1950 (Saros 124) |
 August 22, 1979 (Saros 125) |  August 1, 2008 (Saros 126) |  July 13, 2037 (Saros 127) |
 June 22, 2066 (Saros 128) |  June 2, 2095 (Saros 129) |  May 14, 2124 (Saros 130) |
 April 23, 2153 (Saros 131) |  April 3, 2182 (Saros 132) | |
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