August 1970 lunar eclipse

A partial lunar eclipse occurred at the Moon’s ascending node of orbit on Monday, August 17, 1970, with an umbral magnitude of 0.4080. A lunar eclipse occurs when the Moon moves into the Earth's shadow, 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, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. Occurring only about 4 hours before perigee (on August 17, 1970, at 7:35 UTC), the Moon's apparent diameter was larger.

Visibility

The eclipse was completely visible over eastern North America, South America, west Africa, and Antarctica, seen rising over western North America and the central Pacific Ocean and setting over Europe, much of Africa, and the Middle East.

Eclipse details

Shown below is a table displaying details about this particular lunar eclipse. It describes various parameters pertaining to this eclipse.

Eclipse season

This eclipse is part of an eclipse season, 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.

Related eclipses

Eclipses in 1970

• A partial lunar eclipse on February 21.
• A total solar eclipse on March 7.
• A partial lunar eclipse on August 17.
• An annular solar eclipse on August 31.

Metonic

• Preceded by: Lunar eclipse of October 29, 1966
• Followed by: Lunar eclipse of June 4, 1974

Tzolkinex

• Preceded by: Lunar eclipse of July 6, 1963
• Followed by: Lunar eclipse of September 27, 1977

Half-Saros

• Preceded by: Solar eclipse of August 11, 1961
• Followed by: Solar eclipse of August 22, 1979

Tritos

• Preceded by: Lunar eclipse of September 17, 1959
• Followed by: Lunar eclipse of July 17, 1981

Lunar Saros 118

• Preceded by: Lunar eclipse of August 5, 1952
• Followed by: Lunar eclipse of August 27, 1988

Inex

• Preceded by: Lunar eclipse of September 5, 1941
• Followed by: Lunar eclipse of July 28, 1999

Triad

• Preceded by: Lunar eclipse of October 16, 1883
• Followed by: Lunar eclipse of June 17, 2057

Lunar eclipses of 1969–1973

This eclipse is a member of a semester series. An eclipse in a semester series of lunar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternating nodes of the Moon's orbit.

The penumbral lunar eclipses on April 2, 1969 and September 25, 1969 occur in the previous lunar year eclipse set, and the lunar eclipses on June 15, 1973 (penumbral) and December 10, 1973 (partial) occur in the next lunar year eclipse set.

Metonic series

The Metonic cycle repeats nearly exactly every 19 years and represents a Saros cycle plus one lunar year. Because it occurs on the same calendar date, the Earth's shadow will in nearly the same location relative to the background stars.

Saros 118

This eclipse is a part of Saros series 118, repeating every 18 years, 11 days, and containing 73 events. The series started with a penumbral lunar eclipse on March 2, 1105. It contains partial eclipses from June 8, 1267 through August 12, 1375; total eclipses from August 22, 1393 through June 22, 1880; and a second set of partial eclipses from July 3, 1898 through September 18, 2024. The series ends at member 73 as a penumbral eclipse on May 7, 2403.

The longest duration of totality was produced by member 37 at 99 minutes, 22 seconds on April 7, 1754. All eclipses in this series occur at the Moon’s ascending node of orbit.

Eclipses are tabulated in three columns; every third eclipse in the same column is one exeligmos apart, so they all cast shadows over approximately the same parts of the Earth.

Tritos series

This eclipse is a part of a tritos cycle, repeating at alternating nodes every 135 synodic months (≈ 3986.63 days, or 11 years minus 1 month). Their appearance and longitude are irregular due to a lack of synchronization with the anomalistic month (period of perigee), but groupings of 3 tritos cycles (≈ 33 years minus 3 months) come close (≈ 434.044 anomalistic months), so eclipses are similar in these groupings.

Inex series

This eclipse is a part of the long period inex cycle, repeating at alternating nodes, every 358 synodic months (≈ 10,571.95 days, or 29 years minus 20 days). Their appearance and longitude are irregular due to a lack of synchronization with the anomalistic month (period of perigee). However, groupings of 3 inex cycles (≈ 87 years minus 2 months) comes close (≈ 1,151.02 anomalistic months), so eclipses are similar in these groupings.

Half-Saros cycle

A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros). This lunar eclipse is related to two annular solar eclipses of Solar Saros 125.

See also

• List of lunar eclipses
• List of 20th-century lunar eclipses

Notes

External links

• Eclipse Predictions by Fred Espenak, NASA/GSFC