A partial lunar eclipse occurred at the Moon’s ascending node of orbit on Saturday, August 27, 1988,[1] with an umbral magnitude of 0.2916. 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 7 hours before perigee (on August 17, 1988, at 17:50 UTC), the Moon's apparent diameter was larger.[2]
| Partial eclipse | |||||||||||||
 The Moon's hourly motion shown right to left | |||||||||||||
| Date | August 27, 1988 | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Gamma | −0.8682 | ||||||||||||
| Magnitude | 0.2916 | ||||||||||||
| Saros cycle | 118 (50 of 74) | ||||||||||||
| Partiality | 112 minutes, 58 seconds | ||||||||||||
| Penumbral | 262 minutes, 33 seconds | ||||||||||||
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Visibility
editThe eclipse was completely visible over eastern Australia, western North America, and much of the Pacific Ocean, seen rising over western Australia and the eastern half of Asia and setting over much of North America and South America.[3]
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Eclipse details
editShown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.[4]
| Parameter | Value |
|---|---|
| Penumbral Magnitude | 1.23803 |
| Umbral Magnitude | 0.29159 |
| Gamma | −0.86816 |
| Sun Right Ascension | 10h25m02.1s |
| Sun Declination | +09°54'10.9" |
| Sun Semi-Diameter | 15'50.0" |
| Sun Equatorial Horizontal Parallax | 08.7" |
| Moon Right Ascension | 22h26m40.4s |
| Moon Declination | -10°41'41.3" |
| Moon Semi-Diameter | 16'43.7" |
| Moon Equatorial Horizontal Parallax | 1°01'23.7" |
| ΔT | 56.1 s |
Eclipse season
editThis 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.
| August 27 Ascending node (full moon) |
September 11 Descending node (new moon) |
|---|---|
| |
|
| Partial lunar eclipse Lunar Saros 118 |
Annular solar eclipse Solar Saros 144 |
Related eclipses
editEclipses in 1988
edit- A penumbral lunar eclipse on March 3.
- A total solar eclipse on March 18.
- A partial lunar eclipse on August 27.
- An annular solar eclipse on September 11.
Metonic
edit- Preceded by: Lunar eclipse of November 8, 1984
- Followed by: Lunar eclipse of June 15, 1992
Tzolkinex
edit- Preceded by: Lunar eclipse of July 17, 1981
- Followed by: Lunar eclipse of October 8, 1995
Half-Saros
edit- Preceded by: Solar eclipse of August 22, 1979
- Followed by: Solar eclipse of September 2, 1997
Tritos
edit- Preceded by: Lunar eclipse of September 27, 1977
- Followed by: Lunar eclipse of July 28, 1999
Lunar Saros 118
edit- Preceded by: Lunar eclipse of August 17, 1970
- Followed by: Lunar eclipse of September 7, 2006
Inex
edit- Preceded by: Lunar eclipse of September 17, 1959
- Followed by: Lunar eclipse of August 7, 2017
Triad
edit- Preceded by: Lunar eclipse of October 27, 1901
- Followed by: Lunar eclipse of June 28, 2075
Lunar eclipses of 1988–1991
editThis 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 lunar eclipses on June 27, 1991 (penumbral) and December 21, 1991 (partial) occur in the next lunar year eclipse set.
| Lunar eclipse series sets from 1988 to 1991 | ||||||||
|---|---|---|---|---|---|---|---|---|
| Descending node | Ascending node | |||||||
| Saros | Date Viewing |
Type Chart |
Gamma | Saros | Date Viewing |
Type Chart |
Gamma | |
| 113 | 1988 Mar 03
|
Penumbral
|
0.9886 | 118 | 1988 Aug 27
|
Partial
|
−0.8682 | |
| 123 | 1989 Feb 20
|
Total 
|
0.2935 | 128 | 1989 Aug 17
|
Total
|
−0.1491 | |
| 133 | 1990 Feb 09
|
Total
|
−0.4148 | 138 | 1990 Aug 06
|
Partial
|
0.6374 | |
| 143 | 1991 Jan 30
|
Penumbral
|
−1.0752 | 148 | 1991 Jul 26
|
Penumbral
|
1.4370 | |
Metonic series
editThe 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.
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Saros 118
editThis eclipse is a part of Saros series 118, repeating every 18 years, 11 days, and containing 73 events. The series started with a penumbral lunar eclipse on March 2, 1105. It contains partial eclipses from June 8, 1267 through August 12, 1375; total eclipses from August 22, 1393 through June 22, 1880; and a second set of partial eclipses from July 3, 1898 through September 18, 2024. The series ends at member 73 as a penumbral eclipse on May 7, 2403.
The longest duration of totality was produced by member 37 at 99 minutes, 22 seconds on April 7, 1754. 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 1754 Apr 07, lasting 99 minutes, 22 seconds.[7] | Penumbral | Partial | Total | Central |
| 1105 Mar 02 |
1267 Jun 08 |
1393 Aug 22 |
1465 Oct 04 | |
| Last | ||||
| Central | Total | Partial | Penumbral | |
| 1826 May 21 |
1880 Jun 22 |
2024 Sep 18
|
2403 May 07 | |
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.
| Series members 40–61 occur between 1801 and 2200: | |||||
|---|---|---|---|---|---|
| 40 | 41 | 42 | |||
| 1808 May 10 | 1826 May 21 | 1844 May 31 | |||
| 43 | 44 | 45 | |||
| 1862 Jun 12 | 1880 Jun 22 | 1898 Jul 03 | |||
| 46 | 47 | 48 | |||
| 1916 Jul 15 | 1934 Jul 26 | 1952 Aug 05 | |||
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| 49 | 50 | 51 | |||
| 1970 Aug 17 | 1988 Aug 27 | 2006 Sep 07 | |||
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| 52 | 53 | 54 | |||
| 2024 Sep 18 | 2042 Sep 29 | 2060 Oct 09 | |||
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||
| 55 | 56 | 57 | |||
| 2078 Oct 21 | 2096 Oct 31 | 2114 Nov 12 | |||
| 58 | 59 | 60 | |||
| 2132 Nov 23 | 2150 Dec 04 | 2168 Dec 14 | |||
| 61 | |||||
| 2186 Dec 26 | |||||
Half-Saros cycle
editA 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 125.
| August 22, 1979 | September 2, 1997 |
|---|---|
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See also
editNotes
edit- ^ "August 26–27, 1988 Partial Lunar Eclipse". timeanddate. Retrieved 7 January 2025.
- ^ "Moon Distances for London, United Kingdom, England". timeanddate. Retrieved 7 January 2025.
- ^ "Partial Lunar Eclipse of 1988 Aug 27" (PDF). NASA. Retrieved 7 January 2025.
- ^ "Partial Lunar Eclipse of 1988 Aug 27". EclipseWise.com. Retrieved 7 January 2025.
- ^ van Gent, R.H. "Solar- and Lunar-Eclipse Predictions from Antiquity to the Present". A Catalogue of Eclipse Cycles. Utrecht University. Retrieved 6 October 2018.
- ^ "NASA - Catalog of Lunar Eclipses of Saros 118". eclipse.gsfc.nasa.gov.
- ^ Listing of Eclipses of series 118
- ^ Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros
External links
edit- 1988 Aug 27 chart Eclipse Predictions by Fred Espenak, NASA/GSFC
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