A total

solar eclipse A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby obscuring the view of the Sun from a small part of Earth, totally or partially. Such an alignment occurs approximately every six months, during the eclipse season i ...

occurred at the Moon's

ascending node An orbital node is either of the two points where an orbit intersects a plane of reference to which it is inclined. A non-inclined orbit, which is contained in the reference plane, has no nodes. Planes of reference Common planes of referenc ...

of orbit on Wednesday, October 12, 1977, with a

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

of 1.0269. A

occurs when the

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

passes between

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

and the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

, 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 The angular diameter, angular size, apparent diameter, or apparent size is an angular separation (in units of angle) describing how large a sphere or circle appears from a given point of view. In the vision sciences, it is called the '' visual ...

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. Occurring about 2.6 days before

perigee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...

(on October 15, 1977, at 10:00 UTC), the Moon's apparent diameter was larger. Totality was visible in the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

and

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

. A partial eclipse was visible for parts of

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

, the

Caribbean The Caribbean ( , ; ; ; ) is a region in the middle of the Americas centered around the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean, mostly overlapping with the West Indies. Bordered by North America to the north, Central America ...

, and northern

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

Observations

The

National Geographic Society The National Geographic Society, headquartered in Washington, D.C., United States, is one of the largest nonprofit scientific and educational organizations in the world. Founded in 1888, its interests include geography, archaeology, natural sc ...

funded an expedition by sea led by

Jay Pasachoff Jay Myron Pasachoff (July 1, 1943 – November 20, 2022) was an American astronomer. Pasachoff was Field Memorial Professor of Astronomy at Williams College and the author of textbooks and tradebooks in astronomy, physics, mathematics, and other ...

from

Williams College Williams College is a Private college, private liberal arts colleges in the United States, liberal arts college in Williamstown, Massachusetts, United States. It was established as a men's college in 1793 with funds from the estate of Ephraim ...

Massachusetts Massachusetts ( ; ), officially the Commonwealth of Massachusetts, is a U.S. state, state in the New England region of the Northeastern United States. It borders the Atlantic Ocean and the Gulf of Maine to its east, Connecticut and Rhode ...

to the northeast Pacific Ocean to observe the total eclipse. The team took images of the sky and

corona Corona (from the Latin for 'crown') most commonly refers to: * Stellar corona, the outer atmosphere of the Sun or another star * Corona (beer), a Mexican beer * Corona, informal term for the coronavirus or disease responsible for the COVID-19 ...

during the totality phase as well as corona

spectrum A spectrum (: spectra or spectrums) is a set of related ideas, objects, or properties whose features overlap such that they blend to form a continuum. The word ''spectrum'' was first used scientifically in optics to describe the rainbow of co ...

and

infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...

images.

Eclipse details

Shown below are two tables displaying details about this particular solar eclipse. The first table outlines times at which the moon's penumbra or umbra attains the specific parameter, and the second table describes various other parameters pertaining to this eclipse.

Eclipse season

This eclipse is part of an

eclipse season An eclipse season is a period, roughly every six months, when eclipses occur. Eclipse seasons are the result of the axial parallelism of the Orbit of the Moon, Moon's orbital plane (orbital inclination, tilted five degrees to the ecliptic, Earth ...

, a period, roughly every six months, when eclipses occur. Only two (or occasionally three) eclipse seasons occur each year, and each season lasts about 35 days and repeats just short of six months (173 days) later; thus two full eclipse seasons always occur each year. Either two or three eclipses happen each eclipse season. In the sequence below, each eclipse is separated by a

fortnight A fortnight is a unit of time equal to 14 days (two weeks). The word derives from the Old English term , meaning "" (or "fourteen days", since the Anglo-Saxons counted by nights). Astronomy and tides In astronomy, a ''lunar fortnight'' is hal ...

Related eclipses

Eclipses in 1977

* A partial lunar eclipse on April 4. * An annular solar eclipse on April 18. * A penumbral lunar eclipse on September 27. * A total solar eclipse on October 12.

Metonic

* Preceded by: Solar eclipse of December 24, 1973 * Followed by: Solar eclipse of July 31, 1981

Tzolkinex

* Preceded by: Solar eclipse of August 31, 1970 * Followed by:

Solar eclipse of November 22, 1984 A total solar eclipse occurred at the Moon's descending node of orbit between Thursday, November 22 and Friday, November 23, 1984, with a magnitude of 1.0237. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally o ...

Half-Saros

* Preceded by: Lunar eclipse of October 6, 1968 * Followed by: Lunar eclipse of October 17, 1986

Tritos

* Preceded by:

Solar eclipse of November 12, 1966 A total solar eclipse occurred at the Moon's descending node of orbit on Saturday, November 12, 1966, with a magnitude of 1.0234. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image ...

* Followed by:

Solar eclipse of September 11, 1988 An annular solar eclipse occurred at the Moon's descending node of orbit on Sunday, September 11, 1988, with a magnitude of 0.9377. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the imag ...

Solar Saros 143

* Preceded by:

Solar eclipse of October 2, 1959 A total solar eclipse occurred at the Moon's ascending node of orbit on Friday, October 2, 1959, with a magnitude of 1.0325. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of th ...

* Followed by:

Solar eclipse of October 24, 1995 Solar may refer to: Astronomy * Of or relating to the Sun ** Solar telescope, a special purpose telescope used to observe the Sun ** A device that utilizes solar energy (e.g. "solar panels") ** Solar calendar, a calendar whose dates indicate t ...

Inex

* Preceded by:

Solar eclipse of November 1, 1948 A total solar eclipse occurred at the Moon's descending node of orbit on Monday, November 1, 1948, with a magnitude of 1.0231. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of ...

* Followed by: Solar eclipse of September 22, 2006

Triad

* Preceded by: Solar eclipse of December 12, 1890 * Followed by: Solar eclipse of August 12, 2064

Solar eclipses of 1975–1978

Saros 143

Metonic series

Tritos series

Inex series

Notes

References

{{commons category, Solar eclipse of 1977 October 12 1977 10 12 1977 in science 1977 10 12 October 1977