Solar eclipse of June 30, 1973

Solar eclipse of June 30, 1973
Map
Type of eclipse
Nature	Total
Gamma	−0.0785
Magnitude	1.0792
Maximum eclipse
Duration	424 s (7 min 4 s)
Coordinates	18°48′N5°36′E / 18.8°N 5.6°E / 18.8; 5.6
Max. width of band	256 km (159 mi)
Times (UTC)
Greatest eclipse	11:38:41
References
Saros	136 (35 of 71)
Catalog # (SE5000)	9450

A total solar eclipse occurred at the Moon's descending node of the orbit on Saturday, June 30, 1973. ^[1] 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.

With a maximum eclipse of 92 total minutes and 3.55 seconds, this was the last total solar eclipse that exceeds 60 minutes in this series. There will not be a longer total solar eclipse until June 25, 2150.

The greatest eclipse occurred in the Agadez area in the northwest of Niger not far from Algeria inside the Sahara Desert somewhat 40 km east of the small mountain of Ebenenanoua at 18.8 N and 5.6 E and occurred at 11:38 UTC.

The umbral portion of the path started near the border of Guyana and the Brazilian state Roraima, passed northern Dutch Guiana (today's Suriname), headed into the Atlantic, included one of the Portuguese Cape Verde (today's Cape Verde) Islands, which was Santo Antão, Nouadhibou and Nouakchott and other parts of Central Mauritania, northern Mali, the southernmost of Algeria, the middle and southeastern Niger, the middle of Chad, the Sudan including Darfur and parts that are now in the South Sudan including Kodok, a part of the northernmost Uganda, a part of northern Kenya, the southernmost of Somalia, and the Alphonse Group of British Seychelles (today's Seychelles).

Observations

This eclipse was observed by a group of scientists, which included Donald Liebenberg, from the Los Alamos National Laboratory. They used two airplanes to extend the apparent time of totality by flying along the eclipse path in the same direction as the Moon's shadow as it passed over Africa. One of the planes was a prototype (c/n 001) of what was later to become the Concorde, which has a top speed of almost 1,300 miles per hour (2,100 km/h) (Mach 2). This enabled scientists from Los Alamos, the Paris Observatory, the Kitt Peak National Observatory, Queen Mary University of London, the University of Aberdeen and CNRS to extend totality to more than 74 minutes; nearly 10 times longer than is possible when viewing a total solar eclipse from a stationary location. ^[2] The Concorde was specially modified with rooftop portholes for the mission, and is currently on display with the Solar Eclipse mission livery at Musée de l’air et de l’espace. ^[3] The data gathered resulted in three papers published in Nature ^[4] and a book. ^[5]

The eclipse was also observed by a charter flight from Mount San Antonio College in Southern California. The DC-8 with 150 passengers intercepted the eclipse at 35,000 feet (11,000 m) just off the east coast of Africa and tracked the eclipse for three minutes. The passengers rotated seats every 20 seconds so that each passenger had three 20 second opportunities at the window to observe and take pictures. A separate observation opportunity was provided on a specialized commercial cruise by the S.S. Canberra, which traveled from New York City to the Canary Islands and Dakar, Senegal, observing 5 minutes and 44 seconds of totality out in the Atlantic between those two stops in Africa. ^{[6] [7]} That cruise's passengers included notables in the scientific community such as Neil Armstrong, Scott Carpenter, Isaac Asimov, Walter Sullivan, and the then 15-years old Neil deGrasse Tyson. ^{[8] [9]}

Related eclipses

Eclipses in 1973

• An annular solar eclipse on Thursday, 4 January 1973.
• A penumbral lunar eclipse on Thursday, 18 January 1973.
• A penumbral lunar eclipse on Friday, 15 June 1973.
• A total solar eclipse on Saturday, 30 June 1973.
• A penumbral lunar eclipse on Sunday, 15 July 1973.
• A partial lunar eclipse on Monday, 10 December 1973.
• An annular solar eclipse on Monday, 24 December 1973.

Solar eclipses of 1971–1974

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. ^[10]

Note: Partial solar eclipses on February 25, 1971 and August 20, 1971 occur in the next lunar year set.

Solar eclipse series sets from 1971 to 1974
Descending node				Ascending node
Saros	Map	Gamma		Saros	Map	Gamma
116	1971 July 22 Partial	1.51298		121	1972 January 16 Annular	−0.93651
126	1972 July 10 Total	0.68719		131	1973 January 4 Annular	−0.26441
136	1973 June 30 Total	−0.07853		141	1973 December 24 Annular	0.41710
146	1974 June 20 Total	−0.82388		151	1974 December 13 Partial	1.07974

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. ^[11]

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

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.

22 eclipse events between September 12, 1931 and July 1, 2011.
September 11-12	June 30-July 1	April 17-19	February 4-5	November 22-23
114	116	118	120	122
September 12, 1931	June 30, 1935	April 19, 1939	February 4, 1943	November 23, 1946
124	126	128	130	132
September 12, 1950	June 30, 1954	April 19, 1958	February 5, 1962	November 23, 1965
134	136	138	140	142
September 11, 1969	June 30, 1973	April 18, 1977	February 4, 1981	November 22, 1984
144	146	148	150	152
September 11, 1988	June 30, 1992	April 17, 1996	February 5, 2000	November 23, 2003
154	156
September 11, 2007	July 1, 2011

Notes

1. Hatherill, Chris (March 9, 2016). "When Astronomers Chased a Total Eclipse in a Concorde".
2. Mulkin, Barb (1981). "In Flight: The Story of Los Alamos Eclipse Missions" (PDF). Los Alamos National Laboratory. p. 42. Retrieved 2010-07-14.
3. Chris Hatherill (9 March 2016). "When Astronomers Chased a Total Eclipse in a Concorde". Motherboard. Vice.
4. Hatherill, Chris (9 March 2016). "When Astronomers Chased a Total Eclipse in a Concorde". Vice . Retrieved 10 March 2016.
5. Léna, Pierre (2015). Racing the Moon's Shadow with Concorde 001. Springer. ISBN   978-3-319-21729-1 . Retrieved 10 March 2016.
6. Stewart Leber, Bay (July 12, 1973). "Voyage to Darkness". Honolulu Star-Ledger. Honolulu. Retrieved February 12, 2020.
7. Sullivan, Walter (July 1, 1973). "Rare Eclipse Sweeps Across Width of Africa". The New York Times. New York. Retrieved February 12, 2020.
8. Asimov, Isaac (April 1, 1980). In Joy Still Felt . Doubleday. ISBN   9780385155441.
9. DeGrasse Tyson, Neil (May 1, 2004). The Sky is Not the Limit. Prometheus Books. ISBN   9781616141202.
10. 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.
11. SEsaros136 at NASA.gov

References

• Foto Solar eclipse of June 30, 1973
• Foto Solar eclipse of June 30, 1995 from Russia expedition Archived August 9, 2009, at the Wayback Machine