A partial lunar eclipse occurred at the Moon’s descending node of orbit on Saturday, December 21, 1991, with an umbral magnitude of 0.0876. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A partial lunar eclipse occurs when one part of the Moon is in the Earth's umbra, while the other part is in 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 only about 23 hours before perigee (on December 22, 1991, at 9:25 UTC), the Moon's apparent diameter was larger.
This eclipse was the last of four lunar eclipses in 1991, with the others occurring on January 30 (penumbral), June 27 (penumbral), and July 26 (penumbral).
Visibility The eclipse was completely visible over northeast Asia, much of North America, and much of the Pacific Ocean, seen rising over central, south, and east Asia, and Australia and setting over South America and northern Europe.
Eclipse details Shown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.
+December 21, 1991 Lunar Eclipse Parameters Parameter Value Penumbral Magnitude 1.06511 Umbral Magnitude 0.08762 Gamma 0.97094 Sun Right Ascension 17h55m52.1s Sun Declination -23°26'13.9" Sun Semi-Diameter 16'15.5" Sun Equatorial Horizontal Parallax 08.9" Moon Right Ascension 05h56m15.5s Moon Declination +24°25'15.3" Moon Semi-Diameter 16'38.0" Moon Equatorial Horizontal Parallax 1°01'02.6" ΔT 58.3 s
Eclipse season
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.
+ Eclipse season of December 1991–January 1992 December 21Descending node (full moon) January 4Ascending node (new moon) Partial lunar eclipseLunar Saros 115 Annular solar eclipseSolar Saros 141
Related eclipses Eclipses in 1991 An annular solar eclipse on January 15. A penumbral lunar eclipse on January 30. A penumbral lunar eclipse on June 27. A total solar eclipse on July 11. A penumbral lunar eclipse on July 26. A partial lunar eclipse on December 21.
Metonic Preceded by: Lunar eclipse of March 3, 1988 Followed by: Lunar eclipse of October 8, 1995
Tzolkinex Preceded by: Lunar eclipse of November 8, 1984 Followed by: Lunar eclipse of January 31, 1999
Half-Saros Preceded by: Solar eclipse of December 15, 1982 Followed by: Solar eclipse of December 25, 2000
Tritos Preceded by: Lunar eclipse of January 20, 1981 Followed by: Lunar eclipse of November 20, 2002
Lunar Saros 115 Preceded by: Lunar eclipse of December 10, 1973 Followed by: Lunar eclipse of December 31, 2009
Inex Preceded by: Lunar eclipse of January 9, 1963 Followed by: Lunar eclipse of November 30, 2020
Triad Preceded by: Lunar eclipse of February 19, 1905 Followed by: Lunar eclipse of October 21, 2078
Lunar eclipses of 1991–1994
Metonic series
Saros 115
Tritos series
Inex series
Half-Saros cycle A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros).Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros This lunar eclipse is related to two partial solar eclipses of Solar Saros 122. December 15, 1982December 25, 2000
See also List of lunar eclipses List of 20th-century lunar eclipses
References
External links Saros cycle 115