December 1983 lunar eclipse

December 1983 lunar eclipse

Penumbral eclipse
The Moon's hourly motion shown right to left
Date	December 20, 1983
Gamma	1.0747
Magnitude	−0.1167
Saros cycle	144 (14 of 71)
Penumbral	242 minutes, 15 seconds
Contacts (UTC) P1 23:47:59 Greatest 1:49:04 P4 3:50:14
← June 1983 May 1984 →

A penumbral lunar eclipse occurred at the Moon’s ascending node of orbit on Tuesday, December 20, 1983,^[1] with an umbral magnitude of −0.1167. 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 2.7 days before perigee (on December 22, 1983, at 18:25 UTC), the Moon's apparent diameter was larger.^[2]

The eclipse was completely visible over much of North America, South America, Europe, much of Africa, and west and north Asia, seen rising over western North America and the eastern Pacific Ocean and setting over southeast Africa and central and south Asia.^[3]

Shown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.^[4]

December 20, 1983 Lunar Eclipse Parameters

Parameter	Value
Penumbral Magnitude	0.88903
Umbral Magnitude	−0.11673
Gamma	1.07468
Sun Right Ascension	17h49m31.1s
Sun Declination	-23°25'11.7"
Sun Semi-Diameter	16'15.5"
Sun Equatorial Horizontal Parallax	08.9"
Moon Right Ascension	05h48m58.9s
Moon Declination	+24°28'31.2"
Moon Semi-Diameter	16'09.9"
Moon Equatorial Horizontal Parallax	0°59'19.5"
ΔT	53.7 s

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 1983

December 4 Descending node (new moon)	December 20 Ascending node (full moon)
Annular solar eclipse Solar Saros 132	Penumbral lunar eclipse Lunar Saros 144

• A total solar eclipse on June 11.
• A partial lunar eclipse on June 25.
• An annular solar eclipse on December 4.
• A penumbral lunar eclipse on December 20.

• Preceded by: Lunar eclipse of March 1, 1980
• Followed by: Lunar eclipse of October 7, 1987

• Preceded by: Lunar eclipse of November 6, 1976
• Followed by: Lunar eclipse of January 30, 1991

• Preceded by: Solar eclipse of December 13, 1974
• Followed by: Solar eclipse of December 24, 1992

• Preceded by: Lunar eclipse of January 18, 1973
• Followed by: Lunar eclipse of November 18, 1994

• Preceded by: Lunar eclipse of December 8, 1965
• Followed by: Lunar eclipse of December 30, 2001

• Preceded by: Lunar eclipse of January 8, 1955
• Followed by: Lunar eclipse of November 28, 2012

• Preceded by: Lunar eclipse of February 17, 1897
• Followed by: Lunar eclipse of October 19, 2070

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 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.

Lunar eclipse series sets from 1980 to 1984
Descending node					Ascending node
Saros	Date Viewing	Type Chart	Gamma		Saros	Date Viewing	Type Chart	Gamma
109	1980 Jul 27	Penumbral	1.4139		114	1981 Jan 20	Penumbral	−1.0142
119	1981 Jul 17	Partial	0.7045		124	1982 Jan 09	Total	−0.2916
129	1982 Jul 06	Total	−0.0579		134	1982 Dec 30	Total	0.3758
139	1983 Jun 25	Partial	−0.8152		144	1983 Dec 20	Penumbral	1.0747
149	1984 Jun 13	Penumbral	−1.5240

Lunar Saros series 144, repeating every 18 years and 11 days, has a total of 71 lunar eclipse events including 20 total lunar eclipses.

First Penumbral Lunar Eclipse: 1749 Jul 29

First Partial Lunar Eclipse: 2146 Mar 28

First Total Lunar Eclipse: 2308 Jul 04

First Central Lunar Eclipse: 2362 Aug 06

Greatest Eclipse of the Lunar Saros 144: 2416 Sep 07

Last Central Lunar Eclipse: 2488 Oct 20

Last Total Lunar Eclipse: 2651 Jan 28

Last Partial Lunar Eclipse: 2867 Jun 08

Last Penumbral Lunar Eclipse: 3011 Sep 04

A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros).^[6] This lunar eclipse is related to two partial solar eclipses of Solar Saros 151.

December 13, 1974	December 24, 1992

• List of lunar eclipses
• List of 20th-century lunar eclipses

• 1983 Dec 20 chart Eclipse Predictions by Fred Espenak, NASA/GSFC