| Solar eclipse of June 30, 1973 | |
|---|---|
 Map | |
| Type of eclipse | |
| Nature | Total |
| Gamma | −0.0785 |
| Magnitude | 1.0792 |
| Maximum eclipse | |
| Duration | 424 sec (7 m 4 s) |
| Coordinates | 18°48′N 5°36′E / 18.8°N 5.6°E |
| 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 7 minutes and 3.55 seconds, this was the last total solar eclipse that exceeds 7 minutes in this series. The last total eclipse over 7 minutes was on July 1, 1098 which lasted 7 minutes and 5 seconds. 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).
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]
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 1971–1974 | ||||||
|---|---|---|---|---|---|---|
| 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 | |
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 |
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 | |||
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