| Annular eclipse | |
 Map | |
| Gamma | 0.219 |
|---|---|
| Magnitude | 0.9394 |
| Maximum eclipse | |
| Duration | 450 s (7 min 30 s) |
| Coordinates | 19°12′N128°30′W / 19.2°N 128.5°W /19.2; -128.5 |
| Max. width of band | 230 km (140 mi) |
| Times (UTC) | |
| Greatest eclipse | 20:21:21 |
| References | |
| Saros | 128 (54 of 73) |
| Catalog # (SE5000) | 9375 |
An annularsolar eclipse occurred at the Moon'sdescending node of orbit on Sunday, April 7, 1940,[1] with amagnitude of 0.9394. 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 about 2.4 days afterapogee (on April 5, 1940, at 10:00 UTC), the Moon's apparent diameter was smaller.[2]
Annularity was visible fromGilbert and Ellice Islands (the part now belonging toKiribati),Mexico andTexas,Louisiana,Mississippi,Alabama,Georgia,Florida, andSouth Carolina in theUnited States. A partial eclipse was visible for parts of easternOceania,Hawaii,North America,Central America, theCaribbean, and northernSouth America.
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 | 1940 April 7 at 17:17:50.2 UTC |
| First Umbral External Contact | 1940 April 7 at 18:23:22.6 UTC |
| First Central Line | 1940 April 7 at 18:26:03.9 UTC |
| First Umbral Internal Contact | 1940 April 7 at 18:28:45.3 UTC |
| First Penumbral Internal Contact | 1940 April 7 at 19:37:26.3 UTC |
| Ecliptic Conjunction | 1940 April 7 at 20:18:43.9 UTC |
| Greatest Eclipse | 1940 April 7 at 20:21:20.8 UTC |
| Greatest Duration | 1940 April 7 at 20:26:12.0 UTC |
| Equatorial Conjunction | 1940 April 7 at 20:29:05.3 UTC |
| Last Penumbral Internal Contact | 1940 April 7 at 21:05:02.9 UTC |
| Last Umbral Internal Contact | 1940 April 7 at 22:13:51.7 UTC |
| Last Central Line | 1940 April 7 at 22:16:31.8 UTC |
| Last Umbral External Contact | 1940 April 7 at 22:19:11.6 UTC |
| Last Penumbral External Contact | 1940 April 7 at 23:24:44.5 UTC |
| Parameter | Value |
|---|---|
| Eclipse Magnitude | 0.93942 |
| Eclipse Obscuration | 0.88252 |
| Gamma | 0.21897 |
| Sun Right Ascension | 01h05m52.5s |
| Sun Declination | +07°00'32.1" |
| Sun Semi-Diameter | 15'58.2" |
| Sun Equatorial Horizontal Parallax | 08.8" |
| Moon Right Ascension | 01h05m38.8s |
| Moon Declination | +07°11'53.1" |
| Moon Semi-Diameter | 14'47.0" |
| Moon Equatorial Horizontal Parallax | 0°54'15.4" |
| ΔT | 24.5 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. The first and last eclipse in this sequence is separated by onesynodic month.
| March 23 Ascending node (full moon) | April 7 Descending node (new moon) | April 22 Ascending node (full moon) |
|---|---|---|
 | |  |
| Penumbral lunar eclipse Lunar Saros 102 | Annular solar eclipse Solar Saros 128 | Penumbral lunar eclipse Lunar Saros 140 |
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 onAugust 12, 1942 occurs in the next lunar year eclipse set.
| Solar eclipse series sets from 1939 to 1942 | ||||||
|---|---|---|---|---|---|---|
| Descending node | Ascending node | |||||
| Saros | Map | Gamma | Saros | Map | Gamma | |
| 118 | April 19, 1939 Annular | 0.9388 | 123 | October 12, 1939 Total | −0.9737 | |
| 128 | April 7, 1940 Annular | 0.219 | 133 | October 1, 1940 Total | −0.2573 | |
| 138 | March 27, 1941 Annular | −0.5025 | 143 | September 21, 1941 Total | 0.4649 | |
| 148 | March 16, 1942 Partial | −1.1908 | 153 | September 10, 1942 Partial | 1.2571 | |
This eclipse is a part ofSaros series 128, repeating every 18 years, 11 days, and containing 73 events. The series started with a partial solar eclipse on August 29, 984 AD. It contains total eclipses from May 16, 1417 through June 18, 1471; hybrid eclipses from June 28, 1489 through July 31, 1543; and annular eclipses from August 11, 1561 through July 25, 2120. The series ends at member 73 as a partial eclipse on November 1, 2282. 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 27 at 1 minutes, 45 seconds on June 7, 1453, and the longest duration of annularity was produced by member 48 at 8 minutes, 35 seconds on February 1, 1832. All eclipses in this series occur at the Moon’sdescending node of orbit.[5]
| Series members 47–68 occur between 1801 and 2200: | ||
|---|---|---|
| 47 | 48 | 49 |
 January 21, 1814 |  February 1, 1832 |  February 12, 1850 |
| 50 | 51 | 52 |
 February 23, 1868 |  March 5, 1886 |  March 17, 1904 |
| 53 | 54 | 55 |
 March 28, 1922 | April 7, 1940 |  April 19, 1958 |
| 56 | 57 | 58 |
 April 29, 1976 |  May 10, 1994 |  May 20, 2012 |
| 59 | 60 | 61 |
 June 1, 2030 |  June 11, 2048 |  June 22, 2066 |
| 62 | 63 | 64 |
 July 3, 2084 |  July 15, 2102 |  July 25, 2120 |
| 65 | 66 | 67 |
 August 5, 2138 |  August 16, 2156 |  August 27, 2174 |
| 68 | ||
 September 6, 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 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 | |
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 | ||||
|---|---|---|---|---|
 April 14, 1809 (Saros 116) |  March 14, 1820 (Saros 117) |  February 12, 1831 (Saros 118) |  January 11, 1842 (Saros 119) |  December 11, 1852 (Saros 120) |
 November 11, 1863 (Saros 121) |  October 10, 1874 (Saros 122) |  September 8, 1885 (Saros 123) |  August 9, 1896 (Saros 124) |  July 10, 1907 (Saros 125) |
 June 8, 1918 (Saros 126) |  May 9, 1929 (Saros 127) | April 7, 1940 (Saros 128) |  March 7, 1951 (Saros 129) |  February 5, 1962 (Saros 130) |
 January 4, 1973 (Saros 131) |  December 4, 1983 (Saros 132) |  November 3, 1994 (Saros 133) |  October 3, 2005 (Saros 134) |  September 1, 2016 (Saros 135) |
 August 2, 2027 (Saros 136) |  July 2, 2038 (Saros 137) |  May 31, 2049 (Saros 138) |  April 30, 2060 (Saros 139) |  March 31, 2071 (Saros 140) |
 February 27, 2082 (Saros 141) |  January 27, 2093 (Saros 142) |  December 29, 2103 (Saros 143) |  November 27, 2114 (Saros 144) |  October 26, 2125 (Saros 145) |
 September 26, 2136 (Saros 146) |  August 26, 2147 (Saros 147) |  July 25, 2158 (Saros 148) |  June 25, 2169 (Saros 149) |  May 24, 2180 (Saros 150) |
 April 23, 2191 (Saros 151) | ||||
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 | ||
|---|---|---|
 June 26, 1824 (Saros 124) |  June 6, 1853 (Saros 125) |  May 17, 1882 (Saros 126) |
 April 28, 1911 (Saros 127) | April 7, 1940 (Saros 128) |  March 18, 1969 (Saros 129) |
 February 26, 1998 (Saros 130) |  February 6, 2027 (Saros 131) |  January 16, 2056 (Saros 132) |
 December 27, 2084 (Saros 133) |  December 8, 2113 (Saros 134) |  November 17, 2142 (Saros 135) |
 October 29, 2171 (Saros 136) |  October 9, 2200 (Saros 137) | |
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