Solar eclipse of July 11, 1991

Solar eclipse of July 11, 1991
Solar eclipse of July 11, 1991
	Totality from Playas del Coco, Costa Rica
	Map
Type of eclipse
Nature	Total
Gamma	-0.0041
Magnitude	1.08
Maximum eclipse
Duration	413 sec (6 m 53 s)
Coordinates	22°00′N 105°12′W / 22°N 105.2°W
Max. width of band	258 km (160 mi)
Times (UTC)
(P1) Partial begin	16:28:46
(U1) Total begin	17:21:41
Greatest eclipse	19:07:01
(U4) Total end	20:50:28
(P4) Partial end	21:43:24
References
Saros	136 (36 of 71)
Catalog # (SE5000)	9489

A total solar eclipse occurred on July 11, 1991. 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 began over the Pacific Ocean and Hawaii moving across Mexico, down through Central America and across South America ending over Brazil. It lasted for 6 minutes and 53.08 seconds at the point of maximum eclipse. There will not be a longer total eclipse until June 13, 2132. This was the largest total solar eclipse of Solar Saros series 136, because eclipse magnitude was 1.07997.

This eclipse was the most central total eclipse in 800 years, with a gamma of -.0041. There will not be a more central eclipse for another 800 years. Its magnitude was also greater than any eclipse since the 6th century.

Observations[]

Animation of eclipse path
View near the end of totality, Playas del Coco, Guanacaste, Costa Rica
Partial phase before totality as seen through the cloud cover, Playas del Coco, Guanacaste, Costa Rica

Related eclipses[]

Eclipses of 1991[]

An annular solar eclipse on January 15.
A penumbral lunar eclipse on January 30.
A penumbral lunar eclipse on June 27.
A total solar eclipse on July 11.
A penumbral lunar eclipse on July 26.
A partial lunar eclipse on December 21.

Solar eclipses 1990–1992[]

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] This semester series contains only 7 eclipses.

Solar eclipse series sets from 1990–1992
Ascending node			Descending node
Saros	Map	Gamma	Saros	Map	Gamma
111	1989 February 6	-1.56550	116	1989 August 1	1.58396
121	1990 January 26 Annular	-0.94571	126	1990 July 22 Total	0.75972
131	1991 January 15 Annular	-0.27275	136 From Playas del Coco	1991 July 11 Total	-0.00412
141	1992 January 4 Annular	0.40908	146	1992 June 30 Total	-0.75120
151	1992 December 24 Partial	1.07106	156	1993 June 20	-1.56439

This eclipse is the center of seven central solar eclipses.

Saros 136[]

Solar Saros 136, repeating every 18 years, 11 days, contains 71 events. The series started with partial solar eclipse on June 14, 1360, and reached a first annular eclipse on September 8, 1504. It was a hybrid event from November 22, 1612, through January 17, 1703, and total eclipses from January 27, 1721, through May 13, 2496. The series ends at member 71 as a partial eclipse on July 30, 2622, with the entire series lasting 1262 years. The longest eclipse occurred on June 20, 1955, with a maximum duration of totality at 7 minutes, 7.74 seconds. All eclipses in this series occurs at the Moon's descending node.^[2]

Series members 29–43 occur between 1865 and 2117
29	30	31
Apr 25, 1865	May 6, 1883	May 18, 1901
32	33	34
May 29, 1919	Jun 8, 1937	Jun 20, 1955
35	36	37
Jun 30, 1973	Jul 11, 1991	Jul 22, 2009
38	39	40
Aug 2, 2027	Aug 12, 2045	Aug 24, 2063
41	42	43
Sep 3, 2081	Sep 14, 2099	Sep 26, 2117

Inex series[]

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. In the 18th century:

Solar Saros 127: Total Solar Eclipse of 1731 Jan 08
Solar Saros 128: Annular Solar Eclipse of 1759 Dec 19
Solar Saros 129: Annular Solar Eclipse of 1788 Nov 27

Inex series members between 1801 and 2200:
Near lunar perigee	After lunar apogee Before lunar perigee	Before lunar apogee After lunar perigee
November 9, 1817 (Saros 130)	October 20, 1846 (Saros 131)	September 29, 1875 (Saros 132)
September 9, 1904 (Saros 133)	August 21, 1933 (Saros 134)	July 31, 1962 (Saros 135)
July 11, 1991 (Saros 136)	June 21, 2020 (Saros 137)	May 31, 2049 (Saros 138)
May 11, 2078 (Saros 139)	April 23, 2107 (Saros 140)	April 1, 2136 (Saros 141)
March 12, 2165 (Saros 142)	February 21, 2194 (Saros 143)

In the 23rd century:

Solar Saros 144: Annular Solar Eclipse of 2223 Feb 01
Solar Saros 145: Total Solar Eclipse of 2252 Jan 12
Solar Saros 146: Annular Solar Eclipse of 2280 Dec 22

Tritos series[]

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 1801 and 2100
December 21, 1805 (Saros 119)	November 19, 1816 (Saros 120)	October 20, 1827 (Saros 121)
September 18, 1838 (Saros 122)	August 18, 1849 (Saros 123)	July 18, 1860 (Saros 124)
June 18, 1871 (Saros 125)	May 17, 1882 (Saros 126)	April 16, 1893 (Saros 127)
March 17, 1904 (Saros 128)	February 14, 1915 (Saros 129)	January 14, 1926 (Saros 130)
December 13, 1936 (Saros 131)	November 12, 1947 (Saros 132)	October 12, 1958 (Saros 133)
September 11, 1969 (Saros 134)	August 10, 1980 (Saros 135)	July 11, 1991 (Saros 136)
June 10, 2002 (Saros 137)	May 10, 2013 (Saros 138)	April 8, 2024 (Saros 139)
March 9, 2035 (Saros 140)	February 5, 2046 (Saros 141)	January 5, 2057 (Saros 142)
December 6, 2067 (Saros 143)	November 4, 2078 (Saros 144)	October 4, 2089 (Saros 145)
September 4, 2100 (Saros 146)

In the 22nd century:

Solar saros 147: annular solar eclipse of August 4, 2111
Solar saros 148: total solar eclipse of July 4, 2122
Solar saros 149: total solar eclipse of June 3, 2133
Solar saros 150: annular solar eclipse of May 3, 2144
Solar saros 151: annular solar eclipse of April 2, 2155
Solar saros 152: total solar eclipse of March 2, 2166
Solar saros 153: annular solar eclipse of January 29, 2177
Solar saros 154: annular solar eclipse of December 29, 2187
Solar saros 155: total solar eclipse of November 28, 2198

In the 23rd century:

Solar saros 156: annular solar eclipse of October 29, 2209
Solar saros 157: annular solar eclipse of September 27, 2220
Solar saros 158: total solar eclipse of August 28, 2231
Solar saros 159: partial solar eclipse of July 28, 2242
Solar saros 160: partial solar eclipse of June 26, 2253
Solar saros 161: partial solar eclipse of May 26, 2264
Solar saros 162: partial solar eclipse of April 26, 2275
Solar saros 163: partial solar eclipse of March 25, 2286
Solar saros 164: partial solar eclipse of February 22, 2297

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). All eclipses in this table occur at the Moon's descending node.

21 eclipse events, progressing from north to south between July 11, 1953 and July 11, 2029
July 10–12	April 29–30	February 15–16	December 4–5	September 21–23
116	118	120	122	124
July 11, 1953	April 30, 1957	February 15, 1961	December 4, 1964	September 22, 1968
126	128	130	132	134
July 10, 1972	April 29, 1976	February 16, 1980	December 4, 1983	September 23, 1987
136	138	140	142	144
July 11, 1991	April 29, 1995	February 16, 1999	December 4, 2002	September 22, 2006
146	148	150	152	154
July 11, 2010	April 29, 2014	February 15, 2018	December 4, 2021	September 21, 2025
156	158	160	162	164
July 11, 2029

Notes[]

^ van Gent, R.H. "Solar- and Lunar-Eclipse Predictions from Antiquity to the Present". A Catalogue of Eclipse Cycles. Utrecht University. Retrieved 6 October 2018.
^ SEsaros136 at NASA.gov

References[]

NASA graphics
- Google interactive map of the eclipse from NASA
- NASA Besselian Elements - Total Solar Eclipse of July 11, 1991
Observer's handbook 1991, Editor Roy L. Bishop, The Royal Astronomical Society of Canada (p. 101)

Photos:

Russian scientist observed eclipse
Russia expedition
Baja California, La Paz. Prof. Druckmüller's eclipse photography site
Baja California, Todos Santos. Prof. Druckmüller's eclipse photography site
Reyna from La Paz, Baja California, Mexico
www.noao.edu: Satellite view of eclipse
[1] APOD 7/16/1999, Solar Surfin', total eclipse corona, from Mauna Kea, Hawaii
[2] APOD 10/24/1995, A Total Solar Eclipse, total eclipse corona
The 1991 Eclipse in Mexico

Videos:

Total Solar Eclipse -- July 11, 1991 (9:39 uncut, eclipse full frame, location insert)
Total Solar Eclipse (8:23 edited, includes pre-planning and post-press, music only)
Total Solar Eclipse, Cabo Mexico (9:12 edited, includes some TV news coverage)

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[1] van Gent, R.H. "Solar- and Lunar-Eclipse Predictions from Antiquity to the Present". A Catalogue of Eclipse Cycles. Utrecht University. Retrieved 6 October 2018.

[2] SEsaros136 at NASA.gov

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