Solar eclipse of April 7, 1940

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.[1]

Solar eclipse series sets from 1939–1942
Descending node			Ascending node
Saros	Map		Saros	Map
118	April 19, 1939 Annular		123	October 12, 1939 Total
128	April 7, 1940 Annular		133	October 1, 1940 Total
138	March 27, 1941 Annular		143	September 21, 1941 Total
148	March 16, 1942 Partial		153	September 10, 1942 Partial
The partial solar eclipse on August 12, 1942 occurs in the next lunar year eclipse set.

This eclipse is a member of the Solar Saros cycle 128, which includes 73 eclipses occurring in intervals of 18 years and 11 days. The series started with partial solar eclipse on August 29, 984 AD. From May 16, 1417 through June 18, 1471 the series produced total solar eclipses, followed by hybrid solar eclipses from June 28, 1489 through July 31, 1543, and annular solar eclipses from August 11, 1561 through July 25, 2120. The series ends at member 73 as a partial eclipse on November 1, 2282. All eclipses in this series occurs at the Moon’s descending node.

Series members 52–68 occur between 1901 and 2200
52	53	54
March 17, 1904	March 28, 1922	April 7, 1940
55	56	57
April 19, 1958	April 29, 1976	May 10, 1994
58	59	60
May 20, 2012	June 1, 2030	June 11, 2048
61	62	63
June 22, 2066	July 3, 2084	July 15, 2102
64	65	66
July 25, 2120	August 5, 2138 (Partial)	August 16, 2156 (Partial)
67	68
August 27, 2174 (Partial)	September 6, 2192 (Partial)

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, progressing from north to south between April 8, 1902 and August 31, 1989:
April 7–8	January 24–25	November 12	August 31-September 1	June 19–20
108			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