Solar eclipse of April 7, 1940

An annular solar eclipse occurred at the Moon's descending node of orbit on Sunday, April 7, 1940, 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.

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.

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.

Related eclipses

Eclipses in 1940

• A penumbral lunar eclipse on March 23.
• An annular solar eclipse on April 7.
• A penumbral lunar eclipse on April 22.
• A total solar eclipse on October 1.
• A penumbral lunar eclipse on October 16.

Metonic

• Preceded by: Solar eclipse of June 19, 1936
• Followed by: Solar eclipse of January 25, 1944

Tzolkinex

• Preceded by: Solar eclipse of February 24, 1933
• Followed by: Solar eclipse of May 20, 1947

Half-Saros

• Preceded by: Lunar eclipse of April 2, 1931
• Followed by: Lunar eclipse of April 13, 1949

Tritos

• Preceded by: Solar eclipse of May 9, 1929
• Followed by: Solar eclipse of March 7, 1951

Solar Saros 128

• Preceded by: Solar eclipse of March 28, 1922
• Followed by: Solar eclipse of April 19, 1958

Inex

• Preceded by: Solar eclipse of April 28, 1911
• Followed by: Solar eclipse of March 18, 1969

Triad

• Preceded by: Solar eclipse of June 6, 1853
• Followed by: Solar eclipse of February 6, 2027

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.

The partial solar eclipse on August 12, 1942 occurs in the next lunar year eclipse set.

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.

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.

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.

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.

Notes

• Eclipse Predictions by Fred Espenak, NASA/GSFC