Solar eclipse of October 12, 1977

Solar eclipse of October 12, 1977
Solar eclipse of October 12, 1977
	Map
Type of eclipse
Nature	Total
Gamma	0.3836
Magnitude	1.0269
Maximum eclipse
Duration	157 s (2 min 37 s)
Coordinates	14°06′N 123°36′W / 14.1°N 123.6°W
Max. width of band	99 km (62 mi)
Times (UTC)
Greatest eclipse	20:27:27
References
Saros	143 (21 of 72)
Catalog # (SE5000)	9459

A total solar eclipse occurred at the Moon's ascending node of orbit on Wednesday, October 12, 1977, with a magnitude of 1.0269. 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 in the Pacific Ocean, Colombia and Venezuela.

Observations[edit]

The National Geographic Society funded an expedition by sea led by Jay Pasachoff from Williams College, Massachusetts to the northeast Pacific Ocean to observe the total eclipse. The team took images of the sky and corona during the totality phase as well as corona spectrum and infrared images.^[1]

Related eclipses[edit]

Solar eclipses of 1975–1978[edit]

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]

Solar eclipse series sets from 1975 to 1978
Descending node			Ascending node
Saros	Map	Gamma	Saros	Map	Gamma
118	May 11, 1975 Partial	1.0647	123	November 3, 1975 Partial	−1.0248
128	April 29, 1976 Annular	0.3378	133	October 23, 1976 Total	−0.327
138	April 18, 1977 Annular	−0.399	143	October 12, 1977 Total	0.3836
148	April 7, 1978 Partial	−1.1081	153	October 2, 1978 Partial	1.1616

Saros 143[edit]

This eclipse is a part of Saros series 143, repeating every 18 years, 11 days, and containing 72 events. The series started with a partial solar eclipse on March 7, 1617. It contains total eclipses from June 24, 1797 through October 24, 1995; 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, 2897. 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 16 at 3 minutes, 50 seconds on August 19, 1887, and the longest duration of annularity will be produced by member 51 at 4 minutes, 54 seconds on September 6, 2518. All eclipses in this series occur at the Moon’s ascending node of orbit.^[3]

Series members 12–33 occur between 1801 and 2200:
12	13	14
July 6, 1815	July 17, 1833	July 28, 1851
15	16	17
August 7, 1869	August 19, 1887	August 30, 1905
18	19	20
September 10, 1923	September 21, 1941	October 2, 1959
21	22	23
October 12, 1977	October 24, 1995	November 3, 2013
24	25	26
November 14, 2031	November 25, 2049	December 6, 2067
27	28	29
December 16, 2085	December 29, 2103	January 8, 2122
30	31	32
January 20, 2140	January 30, 2158	February 10, 2176
33
February 21, 2194

Inex series[edit]

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)

Metonic series[edit]

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