Solar eclipse of June 30, 1973

A total solar eclipse occurred at the Moon's descending node of orbit on Saturday, June 30, 1973, with a magnitude of 1.0792. 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. 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 1300 mph (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. 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. The data gathered resulted in three papers published in Nature and a book.

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 35000 ft 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. 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.

Eclipses in 1973

 * An annular solar eclipse on January 4, 1973.
 * A penumbral lunar eclipse on January 18, 1973.
 * A penumbral lunar eclipse on June 15, 1973.
 * A total solar eclipse on June 30, 1973.
 * A penumbral lunar eclipse on July 15, 1973.
 * A partial lunar eclipse on December 10, 1973.
 * An annular solar eclipse on December 24, 1973.

Metonic

 * Preceded by: Solar eclipse of September 11, 1969
 * Followed by: Solar eclipse of April 18, 1977

Tzolkinex

 * Preceded by: Solar eclipse of May 20, 1966
 * Followed by: Solar eclipse of August 10, 1980

Half-Saros

 * Preceded by: Lunar eclipse of June 25, 1964
 * Followed by: Lunar eclipse of July 6, 1982

Tritos

 * Preceded by: Solar eclipse of July 31, 1962
 * Followed by: Solar eclipse of May 30, 1984

Solar Saros 136

 * Preceded by: Solar eclipse of June 20, 1955
 * Followed by: Solar eclipse of July 11, 1991

Inex

 * Preceded by: Solar eclipse of July 20, 1944
 * Followed by: Solar eclipse of June 10, 2002

Triad

 * Preceded by: Solar eclipse of August 29, 1886
 * Followed by: Solar eclipse of April 30, 2060