Solar eclipse of May 20, 1947

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 1946–1949

Ascending node			Descending node
117	1946 May 30 Partial		122	1946 November 23 Partial
127	1947 May 20 Total		132	1947 November 12 Annular
137	1948 May 9 Annular		142	1948 November 1 Total
147	1949 April 28 Partial		152	1949 October 21 Partial

It is a part of Saros cycle 127, repeating every 18 years, 11 days, containing 82 events. The series started with partial solar eclipse on October 10, 991 AD. It contains total eclipses from May 14, 1352 through August 15, 2091. There are no annular eclipses in this series. The series ends at member 82 as a partial eclipse on March 21, 2452. The longest duration of totality was 5 minutes, 40 seconds on August 30, 1532. All eclipses in this series occurs at the Moon’s ascending node.[2]

Series members 52–68 occur between 1901 and 2200
52	53	54
April 28, 1911	May 9, 1929	May 20, 1947
55	56	57
May 30, 1965	June 11, 1983	June 21, 2001
58	59	60
July 2, 2019	July 13, 2037	July 24, 2055
61	62	63
August 3, 2073	August 15, 2091	August 26, 2109 (Partial)
64	65	66
September 6, 2127 (Partial	September 16, 2145 (Partial)	September 28, 2163 (Partial)
67	68
October 8, 2181 (Partial)	October 19, 2199 (Partial)

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 1901 and 2100
September 21, 1903 (Saros 123)	August 21, 1914 (Saros 124)	July 20, 1925 (Saros 125)
June 19, 1936 (Saros 126)	May 20, 1947 (Saros 127)	April 19, 1958 (Saros 128)
March 18, 1969 (Saros 129)	February 16, 1980 (Saros 130)	January 15, 1991 (Saros 131)
December 14, 2001 (Saros 132)	November 13, 2012 (Saros 133)	October 14, 2023 (Saros 134)
September 12, 2034 (Saros 135)	August 12, 2045 (Saros 136)	July 12, 2056 (Saros 137)
June 11, 2067 (Saros 138)	May 11, 2078 (Saros 139)	April 10, 2089 (Saros 140)
March 10, 2100 (Saros 141)

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 24, 1916 and July 31, 2000
December 24–25	October 12–13	July 31-Aug 1	May 18–20	March 7–8
91	93	95	97	99
December 23, 1878	October 12, 1882	July 31, 1886	May 18, 1890	March 7, 1894
101	103	105	107	109
December 23, 1897	October 12, 1901	August 1, 1905	May 19, 1909	March 8, 1913
111	113	115	117	119
December 24, 1916	October 12, 1920	July 31, 1924	May 19, 1928	March 7, 1932
121	123	125	127	129
December 25, 1935	October 12, 1939	August 1, 1943	May 20, 1947	March 7, 1951
131	133	135	137	139
December 25, 1954	October 12, 1958	July 31, 1962	May 20, 1966	March 7, 1970
141	143	145	147	149
December 24, 1973	October 12, 1977	July 31, 1981	May 19, 1985	March 7, 1989
151	153	155	157	159
December 24, 1992	October 12, 1996	July 31, 2000	May 19, 2004	March 7, 2008
161	163	165	167	169
December 24, 2011	October 13, 2015	August 1, 2019	May 19, 2023	March 8, 2027