A total lunar eclipse occurred at the Moon’s ascending node of orbit on Friday, March 24, 1978,[1] with an umbral magnitude of 1.4518. It was a central lunar eclipse, in which part of the Moon passed through the center of the Earth's shadow. 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. The Moon's apparent diameter was near the average diameter because it occurred 7.1 days after apogee (on March 17, 1978, at 14:25 UTC) and 6.6 days before perigee (on March 31, 1978, at 5:45 UTC).[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 July 27, 1980 occurs in the next lunar year eclipse set.
This eclipse is a part of Saros series 122, repeating every 18 years, 11 days, and containing 74 events. The series started with a penumbral lunar eclipse on August 14, 1022. It contains partial eclipses from April 10, 1419 through June 24, 1545; total eclipses from July 5, 1563 through May 6, 2050; and a second set of partial eclipses from May 17, 2068 through July 21, 2176. The series ends at member 74 as a penumbral eclipse on October 29, 2338.
The longest duration of totality was produced by member 39 at 100 minutes, 5 seconds on October 11, 1707. All eclipses in this series occur at the Moon’s ascending node of orbit.[6]
Greatest
First
The greatest eclipse of the series occurred on 1707 Oct 11, lasting 100 minutes, 5 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.
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 solar eclipses of Solar Saros 129.