A total lunar eclipse occurred at the Moon’s ascending node of orbit on Monday, May 13, 1957,[1] with an umbral magnitude of 1.2982. 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 3.25 days after perigee (on May 9, 1957, at 4:30 UTC), the Moon's apparent diameter was larger.[2]
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.
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.[5]
The penumbral lunar eclipse on January 8, 1955 occurs in the previous lunar year eclipse set, and the penumbral lunar eclipse on April 4, 1958 occurs in the next lunar year eclipse set.
This eclipse is a part of Saros series 130, repeating every 18 years, 11 days, and containing 71 events. The series started with a penumbral lunar eclipse on June 10, 1416. It contains partial eclipses from September 4, 1560 through April 12, 1903; total eclipses from April 22, 1921 through September 11, 2155; and a second set of partial eclipses from September 21, 2173 through May 10, 2552. The series ends at member 71 as a penumbral eclipse on July 26, 2678.
The longest duration of totality will be produced by member 35 at 101 minutes, 53 seconds on June 26, 2029. All eclipses in this series occur at the Moon’s ascending node of orbit.[6]
Greatest
First
The greatest eclipse of the series will occur on 2029 Jun 26, lasting 101 minutes, 53 seconds.[7]
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.
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.
A 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 annular solar eclipses of Solar Saros 137.
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