A penumbral lunar eclipse occurred at the Moon’s ascending node of orbit on Thursday, November 8, 1984,[1] with an umbral magnitude of −0.1825. 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 3.8 days after apogee (on November 4, 1984, at 22:40 UTC), the Moon's apparent diameter was smaller.[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 June 13, 1984 occurs in the previous lunar year eclipse set.
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 be in nearly the same location relative to the background stars.
This eclipse is a part of Saros series 116, repeating every 18 years, 11 days, and containing 73 events. The series started with a penumbral lunar eclipse on March 11, 993 AD. It contains partial eclipses from June 16, 1155 through September 11, 1299; total eclipses from September 21, 1317 through July 11, 1786; and a second set of partial eclipses from July 22, 1804 through October 7, 1930. The series ends at member 73 as a penumbral eclipse on May 14, 2291.
The longest duration of totality was produced by member 40 at 102 minutes, 40 seconds on May 16, 1696. 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 1696 May 16, lasting 102 minutes, 40 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 partial solar eclipses of Solar Saros 123.