Solar eclipse of July 11, 1991

Solar eclipse of July 11, 1991
Totality from Guanacaste, Costa Rica
Map
Type of eclipse
Nature	Total
Gamma	-0.0041
Magnitude	1.08
Maximum eclipse
Duration	6m 53s
Coordinates	22N 105.2W
Max. width of band	258 km
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 partially 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, blocking all direct sunlight, turning day into darkness. Totality occurs in a narrow path across the surface of the Earth, while a partial solar eclipse will be visible over a region thousands of kilometres wide.

Totality beginning 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 8 centuries, with a gamma of -.0041. There will not be a more central eclipse for another 8 centuries. Its magnitude was also greater than any eclipse since the 6th century.

Observations

• 

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

• 

  Partial phase before totality as seen through the cloud cover, Guanacaste, Costa Rica.

• 

  Animation of eclipse path

Related eclipses

Solar eclipses 1990-1992

This set of solar eclipses repeat approximately every 177 days and 4 hours at alternating nodes of the moon's orbit.

Solar eclipse series sets from 1990–1992

Ascending node			Descending node
Saros	Map		Saros	Map
			121	January 26, 1990 Annular
126	July 22, 1990 Total		131	January 15, 1991 Annular
136	July 11, 1991 Total		141	January 4, 1992 Annular
146	June 30, 1992 Total		151	December 24, 1992 Partial

Saros 136

Solar Saros 136, repeating every 18 years, 11 days, contains 71 events. The series started with partial solar eclipse on Jun 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 lasting 1262 years. The longest eclipse occurred on June 20, 1955, with a maximum duration of totality was 7 minutes, 8 seconds.

Series members 29-42 occur between 1865 and 2100:

28	29	30
	April 25, 1865	May 6, 1883
31	32	33
May 18, 1901	May 29, 1919	Jun 8, 1937
34	35	36
Jun 20, 1955	Jun 30, 1973	Jul 11, 1991
37	38	39
Jul 22, 2009	Aug 2, 2027	Aug 12, 2045
40	41	42
Aug. 24, 2063	Sep. 3, 2081	Sep. 14, 2099

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 synchonization with the anomalistic month (period of perigee). However, groupings of 3 inex cycles (≈ 87 years minus 2 months) comes close (≈ 1,151.02 anamolistic months), so eclipses are similar in these groupings.

Inex series members between 1901 and 2100:

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)

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 synchonization 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 are:

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)

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).

This series has 21 eclipse events between July 11, 1953 and July 11, 2029.

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