Solar eclipse of July 11, 1991

A total solar eclipse occurred on Thursday, 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 seconds at the point of maximum eclipse. There will not be a longer total eclipse until June 13, 2132.

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.

Solar eclipse of July 11, 1991
Eclipse CR 1991 a zoom
Totality from Playas del Coco, Costa Rica
SE1991Jul11T
Map
Type of eclipse
NatureTotal
Gamma-0.0041
Magnitude1.08
Maximum eclipse
Duration413 sec (6 m 53 s)
Coordinates22°00′N 105°12′W / 22°N 105.2°W
Max. width of band258 km (160 mi)
Times (UTC)
(P1) Partial begin16:28:46
(U1) Total begin17:21:41
Greatest eclipse19:07:01
(U4) Total end20:50:28
(P4) Partial end21:43:24
References
Saros136 (36 of 71)
Catalog # (SE5000)9489

Observations

SE1991Jul11T

Animation of eclipse path

Eclipse CR 1991 b zoom

View near the end of totality, Playas del Coco, Guanacaste, Costa Rica

Eclipse CR 1991 c zoom

Partial phase before totality as seen through the cloud cover, Playas del Coco, Guanacaste, Costa Rica

Related eclipses

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]

Solar eclipse series sets from 1990–1992
Ascending node   Descending node
Saros Map Saros Map
121 January 26, 1990
SE1990Jan26A
Annular
126 July 22, 1990
SE1990Jul22T
Total
131 January 15, 1991
SE1991Jan15A
Annular
136
Eclipse CR 1991 a zoom
From Playas del Coco
July 11, 1991
SE1991Jul11T
Total
141 January 4, 1992
SE1992Jan04A
Annular
146 June 30, 1992
SE1992Jun30T
Total
151 December 24, 1992
SE1992Dec24P
Partial

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, 8 seconds.[2]

Series members 29–43 occur between 1865 and 2117
29 30 31
SE1865Apr25T
Apr 25, 1865
SE1883May06T
May 6, 1883
SE1901May18T
May 18, 1901
32 33 34
SE1919May29T
May 29, 1919
SE1937Jun08T
Jun 8, 1937
SE1955Jun20T
Jun 20, 1955
35 36 37
SE1973Jun30T
Jun 30, 1973
SE1991Jul11T
Jul 11, 1991
SE2009Jul22T
Jul 22, 2009
38 39 40
SE2027Aug02T
Aug 2, 2027
SE2045Aug12T
Aug 12, 2045
SE2063Aug24T
Aug 24, 2063
41 42 43
SE2081Sep03T
Sep 3, 2081
SE2099Sep14T
Sep 14, 2099
SE2117Sep26T
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 19th century:

• Solar Saros 130: Total Solar Eclipse of 1817 Nov 09

• Solar Saros 131: Annular Solar Eclipse of 1846 Oct 20

• Solar Saros 132: Annular Solar Eclipse of 1875 Sep 29

Inex series members between 1901 and 2100:
SE1904Sep09T
September 9, 1904
(Saros 133)
SE1933Aug21A
August 21, 1933
(Saros 134)
SE1962Jul31A
July 31, 1962
(Saros 135)
SE1991Jul11T
July 11, 1991
(Saros 136)
SE2020Jun21A
June 21, 2020
(Saros 137)
SE2049May31A
May 31, 2049
(Saros 138)
SE2078May11T
May 11, 2078
(Saros 139)

In the 22nd century:

Solar Saros 140: Annular Solar Eclipse of 2107 Apr 23

Solar Saros 141: Annular Solar Eclipse of 2136 Apr 01

Solar Saros 142: Total Solar Eclipse of 2165 Mar 12

Solar Saros 143: Annular Solar Eclipse of 2194 Feb 21

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 1901 and 2100
SE1904Mar17A
March 17, 1904
(Saros 128)
SE1915Feb14A
February 14, 1915
(Saros 129)
SE1926Jan14T
January 14, 1926
(Saros 130)
SE1936Dec13A
December 13, 1936
(Saros 131)
SE1947Nov12A
November 12, 1947
(Saros 132)
SE1958Oct12T
October 12, 1958
(Saros 133)
SE1969Sep11A
September 11, 1969
(Saros 134)
SE1980Aug10A
August 10, 1980
(Saros 135)
SE1991Jul11T
July 11, 1991
(Saros 136)
SE2002Jun10A
June 10, 2002
(Saros 137)
SE2013May10A
May 10, 2013
(Saros 138)
SE2024Apr08T
April 8, 2024
(Saros 139)
SE2035Mar09A
March 9, 2035
(Saros 140)
SE2046Feb05A
February 5, 2046
(Saros 141)
SE2057Jan05T
January 5, 2057
(Saros 142)
SE2067Dec06H
December 6, 2067
(Saros 143)
SE2078Nov04A
November 4, 2078
(Saros 144)
SE2089Oct04T
October 4, 2089
(Saros 145)
SE2100Sep04T
September 4, 2100
(Saros 146)

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).

21 eclipse events, progressing from north to south between July 11, 1953 and July 11, 2029
July 10-11 April 29-30 February 15-16 December 4 September 21-23
116 118 120 122 124
SE1953Jul11P
July 11, 1953
SE1957Apr30A
April 30, 1957
SE1961Feb15T
February 15, 1961
SE1964Dec04P
December 4, 1964
SE1968Sep22T
September 22, 1968
126 128 130 132 134
SE1972Jul10T
July 10, 1972
SE1976Apr29A
April 29, 1976
SE1980Feb16T
February 16, 1980
SE1983Dec04A
December 4, 1983
SE1987Sep23A
September 23, 1987
136 138 140 142 144
SE1991Jul11T
July 11, 1991
SE1995Apr29A
April 29, 1995
SE1999Feb16A
February 16, 1999
SE2002Dec04T
December 4, 2002
SE2006Sep22A
September 22, 2006
146 148 150 152 154
SE2010Jul11T
July 11, 2010
SE2014Apr29A
April 29, 2014
SE2018Feb15P
February 15, 2018
SE2021Dec04T
December 4, 2021
SE2025Sep21P
September 21, 2025
156
SE2029Jul11P

July 11, 2029

Notes

  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

References

Photos:

Videos:

Allais effect

The Allais effect is the alleged anomalous behavior of pendulums or gravimeters which is sometimes purportedly observed during a solar eclipse. The effect was first reported as an anomalous precession of the plane of oscillation of a Foucault pendulum during the solar eclipse of June 30, 1954 by Maurice Allais, a French polymath who went on to win the Nobel Prize in Economics. Allais reported another observation of the effect during the solar eclipse of October 2, 1959 using the paraconical pendulum he invented. This study earned him the 1959 Galabert Prize of the French Astronautical Society and made him a laureate of the U.S. Gravity Research Foundation for his 1959 memoir on gravity. The veracity of the Allais effect remains controversial among the scientific community, as its testing has frequently met with inconsistent or ambiguous results over more than five decades of observation.

Inex

The inex is an eclipse cycle of 10,571.95 days (about 29 years minus 20 days). The cycle was first described in modern times by Crommelin in 1901, but was named by George van den Bergh who studied it half a century later. It has been suggested that the cycle was known to Hipparchos. One inex after an eclipse of a particular saros series there will be an eclipse in the next saros series, unless the latter saros series has come to an end.

It corresponds to:

358 lunations (synodic months)

388.50011 draconitic months

30.50011 eclipse years

383.67351 anomalistic months.The 30.5 eclipse years means that if there is a solar eclipse (or lunar eclipse), then after one inex a New Moon (resp. Full Moon) will take place at the opposite node of the orbit of the Moon, and under these circumstances another eclipse can occur.

Unlike the saros, the inex is not close to an integer number of anomalistic months so successive eclipses are not very similar in their appearance and characteristics. From the remainder of 0.67351, being near ​2⁄3, every third eclipse will have a similar position in the moon's elliptical orbit and apparent diameter, so the quality of the solar eclipse (total versus annular) will repeat in these groupings of 3 cycles (87 years minus 2 months), called triads.

Inex series last much longer than saros series. For example, inex series 30 started in saros series −245 in 9435 BC and will continue well beyond 15,000 AD. But inex series are not unbroken: at the beginning and end of a series, eclipses may fail to occur. However once settled down, inex series are very stable and run for many thousands of years. For example, series 30 has produced eclipses every 29 years since saros series −197 in 8045 BC, including most recently the solar eclipse of February 5, 2000.An inex also is close to an integer number of days (10,571.95) so solar eclipses on average take place at about the same geographical longitude at successive events, although variations of the moon's revolutionary speed at different points of the eclipse mask this relation. In addition sequential events occur at opposite geographical latitudes because the eclipses occur at opposite nodes. This is in contrast to the better known saros, which has a period of about ​6,585 1⁄3 days, so successive solar eclipses tend to take place about 120° in longitude apart on the globe (although at the same node and hence at about the same geographical latitude).

The significance of the inex cycle is not in the prediction, but in the organization of eclipses: any eclipse cycle, and indeed the interval between any two eclipses, can be expressed as a combination of saros and inex intervals.

June 1991 lunar eclipse

A penumbral lunar eclipse took place on Thursday, June 27, 1991, the second of four lunar eclipses in 1991. The moon entered the Earth's penumbra for about 3 hours, and was difficult to see. This lunar eclipse is the predecessor of the Solar eclipse of July 11, 1991.

List of films featuring eclipses

There is a body of films featuring stellar eclipses and eclipses of natural satellites. Compared to other astronomical events featured in films, such as full moons and asteroid strikes, solar eclipses are less commonly seen. When they have featured in films, they often drive the plot and have a portentous presence. NPR's Glen Weldon said that films use eclipses "to signal to audiences that the normal rules have temporarily lifted, and things are about to get weird". The first film to feature a solar eclipse was the 1907 silent film The Eclipse, or the Courtship of the Sun and Moon that featured a solar eclipse as a fantastical consummation between the sun and the moon. Eclipses have been seen as bad omens throughout history, so filmmakers leverage that belief "as visual cues or key plot points", according to The Oregonian's Amy Wang. The most accurate depiction of a solar eclipse in film is seen in the 1961 religious epic film Barabbas due to the filming of an actual solar eclipse during its crucifixion scene (see solar eclipse of February 15, 1961).

Solar 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, 8 seconds.

Solar Saros 136 is for now producing the longest total solar eclipses. It produced the six longest total solar eclipses of the 20th century, three of them over seven minutes long. It also produced the longest total eclipse of the 21st century at 6 min 39 sec, and overall will produce the century's three longest total eclipses. Each eclipse is getting slightly shorter and this series will be surpassed in total eclipse length by Solar Saros 139 (whose eclipses are getting slightly longer) on May 11, 2078. Saros 136 will ultimately produce a total of 44 total eclipses. It produced the most central total eclipse between the years 1209 and 2718 and the greatest magnitude of any eclipse since the year 540 on July 11, 1991.

Solar Saros 136 repeats every 18 years, 11 days, 8 hours. Solar Saros 136 contains 71 events in which of 15 will be partial eclipses and 56 will be umbral eclipses (6 annular, 6 hybrid, 44 total).

Solar eclipse of July 22, 2009

A total solar eclipse occurred on July 22, 2009. It was the longest total solar eclipse during the 21st century. It lasted a maximum of 6 minutes and 39 seconds off the coast of Southeast Asia, causing tourist interest in eastern China, Pakistan, Japan, India, Nepal and Bangladesh.

Solar eclipse of June 13, 2132

A total solar eclipse will occur on June 13, 2132. 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.

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