Solar eclipse of October 12, 1977

There were 8 solar eclipses (at 6 month intervals) between May 11, 1975 and October 2, 1978.

Solar eclipse series sets from 1975–1978
Descending node				Ascending node
Saros	Map	Gamma		Saros	Map	Gamma
118	1975 May 11 Partial	1.06472		123	1975 November 3 Partial	-1.02475
128	1976 April 29 Annular	0.33783		133	1976 October 23 Total	-0.32699
138	1977 April 18 Annular	-0.39903		143	1977 October 12 Total	0.38363
148	1978 April 7 Partial	-1.10812		153	1978 October 2 Partial	1.16164

It is a part of Saros cycle 143, repeating every 18 years, 11 days, containing 72 events. The series started with partial solar eclipse on March 7, 1617 and total event from June 24, 1797 through October 24, 1995. It has hybrid eclipses from November 3, 2013 through December 6, 2067, and annular eclipses from December 16, 2085 through September 16, 2536. The series ends at member 72 as a partial eclipse on April 23, 2873. The longest duration of totality was 3 minutes, 50 seconds on August 19, 1887. All eclipses in this series occurs at the Moon’s ascending node.

Series members 17–28 occur between 1741 and 2100
8	9	10
May 23, 1743	June 3, 1761	June 14, 1779
11	12	13
June 24, 1797	July 6, 1851	July 17, 1833
14	15	16
July 28, 1851	August 7, 1869	August 19, 1887
17	18	19
August 30, 1905	September 10, 1923	September 21, 1941
20	21	22
October 2, 1959	October 12, 1977	October 24, 1995
23	24	25
November 3, 2013	November 14, 2031	November 25, 2049
26	27	28
December 6, 2067	December 16, 2085

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.

Inex series members between 1901 and 2100:
November 22, 1919 (Saros 141)	November 1, 1948 (Saros 142)	October 12, 1977 (Saros 143)
September 22, 2006 (Saros 144)	September 2, 2035 (Saros 145)	August 12, 2064 (Saros 146)
July 23, 2093 (Saros 147)

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