Solar eclipse of October 1, 1940

Solar eclipse of October 1, 1940
Solar eclipse of October 1, 1940
	Map
Type of eclipse
Nature	Total
Gamma	−0.2573
Magnitude	1.0645
Maximum eclipse
Duration	335 s (5 min 35 s)
Coordinates	17°30′S 18°12′W / 17.5°S 18.2°W
Max. width of band	218 km (135 mi)
Times (UTC)
Greatest eclipse	12:44:06
References
Saros	133 (41 of 72)
Catalog # (SE5000)	9376

A total solar eclipse occurred on Tuesday, October 1, 1940. 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. Totality was visible from Colombia, Brazil, Venezuela and South Africa.

Observation

Members of the Joint Solar Eclipses Standing Committee of the Royal Society and Royal Astronomical Society made observations in Brazil with interferometers and spectrometers. Teams of the Royal Observatory, Greenwich and Royal Observatory, Cape of Good Hope (now combined into the South African Astronomical Observatory) went to Calvinia, South Africa to study the gravitational lens proposed by the general relativity. Other scientists went to the edge of the path of totality to study the spectral lines of the solar chromosphere. A joint team of the Heliophysical Observatory of the University of Cambridge and the Radcliffe Observatory in Pretoria, South Africa (now combined into the South African Astronomical Observatory) went to Nelspoort to study the extreme ultraviolet spectrum of the chromosphere and corona, and conducted polarization studies of the corona and sky around the sun^[1].

Related eclipses

Solar eclipses 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.^[2]

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 133

This eclipse is a part of Saros series 133, repeating every 18 years, 11 days, and containing 72 events. The series started with a partial solar eclipse on July 13, 1219. It contains annular eclipses from November 20, 1435 through January 13, 1526; a hybrid eclipse on January 24, 1544; and total eclipses from February 3, 1562 through June 21, 2373. The series ends at member 72 as a partial eclipse on September 5, 2499. 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 annularity was produced by member 25 at 1 minutes, 14 seconds on November 30, 1453, and the longest duration of totality was produced by member 61 at 6 minutes, 50 seconds on August 7, 1850. All eclipses in this series occur at the Moon’s ascending node of orbit.^[3]

Series members 34–55 occur between 1801 and 2200:
34	35	36
July 17, 1814	July 27, 1832	August 7, 1850
37	38	39
August 18, 1868	August 29, 1886	September 9, 1904
40	41	42
September 21, 1922	October 1, 1940	October 12, 1958
43	44	45
October 23, 1976	November 3, 1994	November 13, 2012
46	47	48
November 25, 2030	December 5, 2048	December 17, 2066
49	50	51
December 27, 2084	January 8, 2103	January 19, 2121
52	53	54
January 30, 2139	February 9, 2157	February 21, 2175
55
March 3, 2193

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).

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