A partial

lunar eclipse A lunar eclipse is an astronomical event that occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. Such an alignment occurs during an eclipse season, approximately every six months, during the full moon phase, ...

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 Monday, April 4, 1977, with an umbral

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 0.1929. A lunar eclipse 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 ...

moves into the

Earth's shadow Earth's shadow (or Earth shadow) is the shadow that Earth itself casts through its atmosphere and into outer space, toward the antisolar point. During the twilight period (both early dusk and late dawn), the shadow's visible fringe – someti ...

, causing the Moon to be darkened. A partial lunar eclipse occurs when one part of the Moon is in the Earth's umbra, while the other part is in the Earth's penumbra. Unlike a

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 ...

, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the

night Night, or nighttime, is the period of darkness when the Sun is below the horizon. Sunlight illuminates one side of the Earth, leaving the other in darkness. The opposite of nighttime is daytime. Earth's rotation causes the appearance of ...

side of Earth. Occurring about 1.7 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 April 5, 1977, at 21:50 UTC), the Moon's apparent diameter was larger.

Visibility

The eclipse was completely visible over much 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 ...

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 ...

, and

west Africa West Africa, also known as Western Africa, is the westernmost region of Africa. The United Nations geoscheme for Africa#Western Africa, United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Gha ...

, seen rising over western North America and the central

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 ...

and setting over

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

and the

Middle East The Middle East (term originally coined in English language) is a geopolitical region encompassing the Arabian Peninsula, the Levant, Turkey, Egypt, Iran, and Iraq. The term came into widespread usage by the United Kingdom and western Eur ...

Eclipse details

Shown below is a table displaying details about this particular solar eclipse. It describes various 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: Lunar eclipse of June 15, 1973 * Followed by: Lunar eclipse of January 20, 1981

Tzolkinex

* Preceded by: Lunar eclipse of February 21, 1970 * Followed by: Lunar eclipse of May 15, 1984

Half-Saros

* Preceded by:

Solar eclipse of March 28, 1968 A partial solar eclipse occurred at the Moon's ascending node of orbit between Thursday, March 28 and Friday, March 29, 1968, with a magnitude of 0.899. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or part ...

* Followed by:

Solar eclipse of April 9, 1986 A partial solar eclipse occurred at the Moon's ascending node of orbit on Wednesday, April 9, 1986, with a magnitude of 0.8236. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of ...

Tritos

* Preceded by: Lunar eclipse of May 4, 1966 * Followed by: Lunar eclipse of March 3, 1988

Lunar Saros 112

* Preceded by: Lunar eclipse of March 24, 1959 * Followed by: Lunar eclipse of April 15, 1995

Inex

* Preceded by: Lunar eclipse of April 23, 1948 * Followed by: Lunar eclipse of March 14, 2006

Triad

* Preceded by: Lunar eclipse of June 3, 1890 * Followed by: Lunar eclipse of February 2, 2064

Lunar eclipses of 1977–1980

Saros 112

Tritos series

Inex series

Half-Saros cycle

A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros).Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, ''The half-saros'' This lunar eclipse is related to two partial solar eclipses of

Solar Saros 119 Saros cycle series 119 for solar eclipses occurs at the Moon's ascending node, repeating every 18 years, 11 days, containing 71 eclipses, including 54 umbral eclipses (2 total, 1 hybrid, and 51 annular). The first eclipse was on 15 May 850 and the ...

Notes

External links

* 1977-04 1977 in science April 1977 {{lunar-eclipse-stub