October 1968 lunar eclipse
A total lunar eclipse occurred at the Moon’s ascending node of orbit on Sunday, October 6, 1968,[1] with an umbral magnitude of 1.1691. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. 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. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring about 5.3 days before apogee (on October 11, 1968, at 18:05 UTC), the Moon's apparent diameter was smaller.[2] This lunar eclipse was the last of a tetrad, with four total lunar eclipses in series, the others being on April 24, 1967; October 18, 1967; and April 13, 1968. VisibilityThe eclipse was completely visible over northeast Asia, eastern Australia, northwestern North America and much of the Pacific Ocean, seen rising over most of Asia and western Australia and setting over North and South America.[3] Eclipse detailsShown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.[4]
Eclipse seasonThis 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 eclipsesEclipses in 1968
Metonic
Tzolkinex
Half-Saros
Tritos
Lunar Saros 136
Inex
Triad
Lunar eclipses of 1966–1969This 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.[5] The penumbral lunar eclipse on August 27, 1969 occurs in the next lunar year eclipse set.
Saros 136This eclipse is a part of Saros series 136, repeating every 18 years, 11 days, and containing 72 events. The series started with a penumbral lunar eclipse on April 13, 1680. It contains partial eclipses from July 11, 1824 through September 14, 1932; total eclipses from September 26, 1950 through July 7, 2419; and a second set of partial eclipses from July 18, 2437 through October 3, 2563. The series ends at member 72 as a penumbral eclipse on June 1, 2960. The longest duration of totality will be produced by member 35 at 101 minutes, 23 seconds on April 21, 2293. All eclipses in this series occur at the Moon’s ascending node of orbit.[6]
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 seriesThis 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.
Half-Saros cycleA lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros).[8] This lunar eclipse is related to two total solar eclipses of Solar Saros 143.
See alsoNotes
External links
|