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Solar eclipse of April 28, 1930

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Solar eclipse of April 28, 1930
Map
Type of eclipse
NatureHybrid
Gamma0.473
Magnitude1.0003
Maximum eclipse
Duration1 s (0 min 1 s)
Coordinates39°24′N 121°12′W / 39.4°N 121.2°W / 39.4; -121.2
Max. width of band1 km (0.62 mi)
Times (UTC)
Greatest eclipse19:03:34
References
Saros137 (31 of 70)
Catalog # (SE5000)9351

A total solar eclipse occurred at the Moon's ascending node of orbit on Monday, April 28, 1930,[1] with a magnitude of 1.0003. It was a hybrid event, with only a fraction of its path as total, and longer sections at the start and end as an annular eclipse. 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. A total solar eclipse occurs when the Moon's apparent 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. The Moon's apparent diameter was near the average diameter because it occurred 7.2 days after apogee (on April 21, 1930, at 13:50 UTC) and 6 days before perigee (on May 4, 1930, at 19:50 UTC).[2]

Annularity was first visible in the eastern Pacific Ocean, then totality from California, Nevada, Oregon, Idaho and Montana, with annularity continuing northeast across the remainder of Montana and into central and eastern Canada and northern Labrador of the Dominion of Newfoundland (today's Newfoundland and Labrador in Canada). A partial eclipse was visible for parts of Hawaii, North America, and the northern Soviet Union.

Observations

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During a hybrid solar eclipse, the apex of the moon's umbral cone was very close to the Earth's surface, and the magnitude was very large. The edges of the moon and the sun were very close to each other as seen from the Earth in both the total and annular portion of the path. A series of Baily's beads on the lunar limb provided an excellent opportunity to measure the size and shape of the Earth, as well as the mountains and valleys on the lunar limb. Scientists recorded the precise time of each phase of the eclipse in Camptonville, California. Because the duration of totality was just more than 1 second, the photographic film needed to be inserted quickly after the start of totality. In addition, scientists recorded audio images with a long-wave receiver on an aircraft at the Mare Island Naval Shipyard. Each image had a time accurate to 1/5 second.

Prior to it, the hybrid solar eclipse of April 17, 1912, also belonging to Solar Saros 137, also occurred with a magnitude close to 1. Observations were made near Paris, France. Similar observations were also made during the annular solar eclipses of May 9, 1948 in Rebun Island, Japan and May 20, 1966 in Greece and Turkey, also belonging to the same solar Saros cycle.[3]

Eclipse details

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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.[4]

April 28, 1930 Solar Eclipse Times
Event Time (UTC)
First Penumbral External Contact 1930 April 28 at 16:20:27.5 UTC
First Umbral External Contact 1930 April 28 at 17:25:43.5 UTC
First Central Line 1930 April 28 at 17:26:14.8 UTC
Greatest Duration 1930 April 28 at 17:26:14.8 UTC
First Umbral Internal Contact 1930 April 28 at 17:26:46.1 UTC
Greatest Eclipse 1930 April 28 at 19:03:34.0 UTC
Ecliptic Conjunction 1930 April 28 at 19:08:43.9 UTC
Equatorial Conjunction 1930 April 28 at 19:27:27.4 UTC
Last Umbral Internal Contact 1930 April 28 at 20:40:09.2 UTC
Last Central Line 1930 April 28 at 20:40:37.6 UTC
Last Umbral External Contact 1930 April 28 at 20:41:06.0 UTC
Last Penumbral External Contact 1930 April 28 at 21:46:24.5 UTC
April 28, 1930 Solar Eclipse Parameters
Parameter Value
Eclipse Magnitude 1.00026
Eclipse Obscuration 1.00053
Gamma 0.47305
Sun Right Ascension 02h21m32.7s
Sun Declination +14°06'03.1"
Sun Semi-Diameter 15'52.8"
Sun Equatorial Horizontal Parallax 08.7"
Moon Right Ascension 02h20m46.1s
Moon Declination +14°30'42.8"
Moon Semi-Diameter 15'39.8"
Moon Equatorial Horizontal Parallax 0°57'29.0"
ΔT 24.0 s

Eclipse season

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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 April 1930
April 13
Descending node (full moon)
April 28
Ascending node (new moon)
Partial lunar eclipse
Lunar Saros 111
Hybrid solar eclipse
Solar Saros 137
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Eclipses in 1930

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Metonic

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Tzolkinex

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Half-Saros

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Tritos

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Solar Saros 137

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Inex

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Triad

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Solar eclipses of 1928–1931

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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.[5]

The partial solar eclipse on June 17, 1928 occurs in the previous lunar year eclipse set, and the partial solar eclipse on September 12, 1931 occurs in the next lunar year eclipse set.

Solar eclipse series sets from 1928 to 1931
Ascending node   Descending node
Saros Map Gamma Saros Map Gamma
117 May 19, 1928

Total (non-central)
1.0048 122 November 12, 1928

Partial
1.0861
127 May 9, 1929

Total
−0.2887 132 November 1, 1929

Annular
0.3514
137 April 28, 1930

Hybrid
0.473 142 October 21, 1930

Total
−0.3804
147 April 18, 1931

Partial
1.2643 152 October 11, 1931

Partial
−1.0607

Saros 137

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This eclipse is a part of Saros series 137, repeating every 18 years, 11 days, and containing 70 events. The series started with a partial solar eclipse on May 25, 1389. It contains total eclipses from August 20, 1533 through December 6, 1695; the first set of hybrid eclipses from December 17, 1713 through February 11, 1804; the first set of annular eclipses from February 21, 1822 through March 25, 1876; the second set of hybrid eclipses from April 6, 1894 through April 28, 1930; and the second set of annular eclipses from May 9, 1948 through April 13, 2507. The series ends at member 70 as a partial eclipse on June 28, 2633. 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 11 at 2 minutes, 55 seconds on September 10, 1569, and the longest duration of annularity will be produced by member 59 at 7 minutes, 5 seconds on February 28, 2435. All eclipses in this series occur at the Moon’s ascending node of orbit.[6]

Series members 24–46 occur between 1801 and 2200:
24 25 26

February 11, 1804

February 21, 1822

March 4, 1840
27 28 29

March 15, 1858

March 25, 1876

April 6, 1894
30 31 32

April 17, 1912

April 28, 1930

May 9, 1948
33 34 35

May 20, 1966

May 30, 1984

June 10, 2002
36 37 38

June 21, 2020

July 2, 2038

July 12, 2056
39 40 41

July 24, 2074

August 3, 2092

August 15, 2110
42 43 44

August 25, 2128

September 6, 2146

September 16, 2164
45 46

September 27, 2182

October 9, 2200

Metonic series

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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 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

Tritos series

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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 4, 1810
(Saros 126)

March 4, 1821
(Saros 127)

February 1, 1832
(Saros 128)

December 31, 1842
(Saros 129)

November 30, 1853
(Saros 130)

October 30, 1864
(Saros 131)

September 29, 1875
(Saros 132)

August 29, 1886
(Saros 133)

July 29, 1897
(Saros 134)

June 28, 1908
(Saros 135)

May 29, 1919
(Saros 136)

April 28, 1930
(Saros 137)

March 27, 1941
(Saros 138)

February 25, 1952
(Saros 139)

January 25, 1963
(Saros 140)

December 24, 1973
(Saros 141)

November 22, 1984
(Saros 142)

October 24, 1995
(Saros 143)

September 22, 2006
(Saros 144)

August 21, 2017
(Saros 145)

July 22, 2028
(Saros 146)

June 21, 2039
(Saros 147)

May 20, 2050
(Saros 148)

April 20, 2061
(Saros 149)

March 19, 2072
(Saros 150)

February 16, 2083
(Saros 151)

January 16, 2094
(Saros 152)

December 17, 2104
(Saros 153)

November 16, 2115
(Saros 154)

October 16, 2126
(Saros 155)

September 15, 2137
(Saros 156)

August 14, 2148
(Saros 157)

July 15, 2159
(Saros 158)

June 14, 2170
(Saros 159)

May 13, 2181
(Saros 160)

April 12, 2192
(Saros 161)

Inex series

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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

July 17, 1814
(Saros 133)

June 27, 1843
(Saros 134)

June 6, 1872
(Saros 135)

May 18, 1901
(Saros 136)

April 28, 1930
(Saros 137)

April 8, 1959
(Saros 138)

March 18, 1988
(Saros 139)

February 26, 2017
(Saros 140)

February 5, 2046
(Saros 141)

January 16, 2075
(Saros 142)

December 29, 2103
(Saros 143)

December 7, 2132
(Saros 144)

November 17, 2161
(Saros 145)

October 29, 2190
(Saros 146)

Notes

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  1. ^ "April 28, 1930 Total Solar Eclipse". timeanddate. Retrieved 3 August 2024.
  2. ^ "Moon Distances for London, United Kingdom, England". timeanddate. Retrieved 3 August 2024.
  3. ^ Xavier M. Jubier. "Eclipse hybride de Soleil du 28 avril 1930 depuis l'ouest des États-Unis ou l'est du Canada (Hybrid Solar Eclipse of 1930 April 28 in western USA or eastern Canada)". Archived from the original on 11 January 2019.
  4. ^ "Hybrid Solar Eclipse of 1930 Apr 28". EclipseWise.com. Retrieved 3 August 2024.
  5. ^ van Gent, R.H. "Solar- and Lunar-Eclipse Predictions from Antiquity to the Present". A Catalogue of Eclipse Cycles. Utrecht University. Retrieved 6 October 2018.
  6. ^ "NASA - Catalog of Solar Eclipses of Saros 137". eclipse.gsfc.nasa.gov.

References

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