July 1980 lunar eclipse
A penumbral lunar eclipse occurred at the Moon’s descending node of orbit on Sunday, July 27, 1980,[1] with an umbral magnitude of −0.7263. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A penumbral lunar eclipse occurs when part or all of the Moon's near side passes into 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 about 3.2 days before perigee (on July 30, 1980, at 23:40 UTC), the Moon's apparent diameter was larger.[2] VisibilityThe eclipse was completely visible over central and east Africa, eastern Europe, much of Asia, Australia, and Antarctica, seen rising over western Europe and west Africa and setting over northeast Asia and the western Pacific Ocean.[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. The first and last eclipse in this sequence is separated by one synodic month.
Related eclipsesEclipses in 1980
Metonic
Tzolkinex
Half-Saros
Tritos
Lunar Saros 109
Inex
Triad
Lunar eclipses of 1980–1984This 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 eclipses on March 1, 1980 and August 26, 1980 occur in the previous lunar year eclipse set, and the penumbral lunar eclipses on May 15, 1984 and November 8, 1984 occur in the next lunar year eclipse set.
Saros 109This eclipse is a part of Saros series 109, repeating every 18 years, 11 days, and containing 71 or 72 events (depending on the source). The series started with a penumbral lunar eclipse on June 27, 736 AD. It contains partial eclipses from September 22, 880 AD through April 16, 1223; total eclipses from April 27, 1241 through October 17, 1529; and a second set of partial eclipses from October 28, 1547 through May 22, 1872. The series ends at member 71 as a penumbral eclipse on August 8, 1998, though some sources count a possible penumbral eclipse on August 18, 2016 as the last eclipse of the series. The longest duration of totality was produced by member 35 at 99 minutes, 45 seconds on July 1, 1349. All eclipses in this series occur at the Moon’s descending 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.
Inex seriesThis 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 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 one partial solar eclipse of Solar Saros 116.
See alsoNotes
External links
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