Solar eclipse of April 7, 1940

Solar eclipse of April 7, 1940
Solar eclipse of April 7, 1940
	Map
Type of eclipse
Nature	Annular
Gamma	0.219
Magnitude	0.9394
Maximum eclipse
Duration	450 s (7 min 30 s)
Coordinates	19°12′N 128°30′W / 19.2°N 128.5°W
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 annular solar eclipse occurred at the Moon's descending node of orbit on Sunday, April 7, 1940,^[1] with a magnitude of 0.9394. 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 about 2.4 days after apogee (on April 5, 1940, at 10:00 UTC), the Moon's apparent diameter was smaller.^[2]

Annularity was visible from Gilbert and Ellice Islands (the part now belonging to Kiribati), Mexico and Texas, Louisiana, Mississippi, Alabama, Georgia, Florida, and South Carolina in the United States. A partial eclipse was visible for parts of eastern Oceania, Hawaii, North America, Central America, the Caribbean, and northern South America.

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.^[3]

April 7, 1940 Solar Eclipse Times
Event	Time (UTC)
First Penumbral External Contact	1940 April 07 at 17:17:50.2 UTC
First Umbral External Contact	1940 April 07 at 18:23:22.6 UTC
First Central Line	1940 April 07 at 18:26:03.9 UTC
First Umbral Internal Contact	1940 April 07 at 18:28:45.3 UTC
First Penumbral Internal Contact	1940 April 07 at 19:37:26.3 UTC
Ecliptic Conjunction	1940 April 07 at 20:18:43.9 UTC
Greatest Eclipse	1940 April 07 at 20:21:20.8 UTC
Greatest Duration	1940 April 07 at 20:26:12.0 UTC
Equatorial Conjunction	1940 April 07 at 20:29:05.3 UTC
Last Penumbral Internal Contact	1940 April 07 at 21:05:02.9 UTC
Last Umbral Internal Contact	1940 April 07 at 22:13:51.7 UTC
Last Central Line	1940 April 07 at 22:16:31.8 UTC
Last Umbral External Contact	1940 April 07 at 22:19:11.6 UTC
Last Penumbral External Contact	1940 April 07 at 23:24:44.5 UTC

April 7, 1940 Solar Eclipse Parameters
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

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. The first and last eclipse in this sequence is separated by one synodic month.

Eclipse season of March–April 1940
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

Related eclipses

Solar eclipses of 1939–1942

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 partial solar eclipse on August 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

Saros 128

This eclipse is a part of Saros 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 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 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’s descending 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

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 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

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
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)

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
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)