April 1968 lunar eclipse
Template:Short description Template:Infobox lunar eclipse A total lunar eclipse occurred at the Moon’s descending node of orbit on Saturday, April 13, 1968,[1] with an umbral magnitude of 1.1116. 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. Occurring about 1.1 days before perigee (on April 14, 1968, at 7:50 UTC), the Moon's apparent diameter was larger.[2]
This lunar eclipse was the third of a tetrad, with four total lunar eclipses in series, the others being on April 24, 1967; October 18, 1967; and October 6, 1968.
Visibility
The eclipse was completely visible over much of North America and South America, seen rising over northwestern North America and the central Pacific Ocean and setting over Europe, Africa, and the Middle East.[3]
| File:Lunar eclipse from moon-1968Apr13.png File:Lunar eclipse chart close-1968Apr13.png |
Eclipse details
Shown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.[4]
| Parameter | Value |
|---|---|
| Penumbral Magnitude | 2.07253 |
| Umbral Magnitude | 1.11164 |
| Gamma | −0.41732 |
| Sun Right Ascension | 01h26m19.6s |
| Sun Declination | +09°03'48.7" |
| Sun Semi-Diameter | 15'56.9" |
| Sun Equatorial Horizontal Parallax | 08.8" |
| Moon Right Ascension | 13h25m32.2s |
| Moon Declination | -09°26'23.0" |
| Moon Semi-Diameter | 16'35.8" |
| Moon Equatorial Horizontal Parallax | 1°00'54.7" |
| ΔT | 38.5 s |
Eclipse season
Script error: No such module "Labelled list hatnote". 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.
| March 28 Ascending node (new moon) |
April 13 Descending node (full moon) |
|---|---|
| File:SE1968Mar28P.png | File:Lunar eclipse chart close-1968Apr13.png |
| Partial solar eclipse Solar Saros 119 |
Total lunar eclipse Lunar Saros 131 |
Related eclipses
Eclipses in 1968
- A partial solar eclipse on March 28.
- A total lunar eclipse on April 13.
- A total solar eclipse on September 22.
- A total lunar eclipse on October 6.
Metonic
- Preceded by: Lunar eclipse of June 25, 1964
- Followed by: Lunar eclipse of January 30, 1972
Tzolkinex
- Preceded by: Lunar eclipse of March 2, 1961
- Followed by: Lunar eclipse of May 25, 1975
Half-Saros
- Preceded by: Solar eclipse of April 8, 1959
- Followed by: Solar eclipse of April 18, 1977
Tritos
- Preceded by: Lunar eclipse of May 13, 1957
- Followed by: Lunar eclipse of March 13, 1979
Lunar Saros 131
- Preceded by: Lunar eclipse of April 2, 1950
- Followed by: Lunar eclipse of April 24, 1986
Inex
- Preceded by: Lunar eclipse of May 3, 1939
- Followed by: Lunar eclipse of March 24, 1997
Triad
- Preceded by: Lunar eclipse of June 12, 1881
- Followed by: Lunar eclipse of February 11, 2055
Lunar eclipses of 1966–1969
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 August 27, 1969 occurs in the next lunar year eclipse set.
Saros 131
This eclipse is a part of Saros series 131, repeating every 18 years, 11 days, and containing 72 events. The series started with a penumbral lunar eclipse on May 10, 1427. It contains partial eclipses from July 25, 1553 through March 22, 1932; total eclipses from April 2, 1950 through September 3, 2202; and a second set of partial eclipses from September 13, 2220 through April 9, 2563. The series ends at member 72 as a penumbral eclipse on July 7, 2707.
The longest duration of totality will be produced by member 38 at 100 minutes, 36 seconds on June 28, 2094. All eclipses in this series occur at the Moon’s descending node of orbit.[6]
| Greatest | First | |||
|---|---|---|---|---|
| File:Lunar eclipse chart close-2094Jun28.png The greatest eclipse of the series will occur on 2094 Jun 28, lasting 100 minutes, 36 seconds.[7] |
Penumbral | Partial | Total | Central |
| 1427 May 10 |
1553 Jul 25 |
1950 Apr 02 File:Lunar eclipse chart close-1950Apr02.png |
2022 May 16 File:Lunar eclipse chart close-2022may16.png | |
| Last | ||||
| Central | Total | Partial | Penumbral | |
| 2148 Jul 31 |
2202 Sep 03 |
2563 Apr 09 |
2707 Jul 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.
Tritos series
Template:Lunar Tritos series January 2001
Inex series
This eclipse is a part of the long period inex cycle, repeating at alternating nodes, every 358 synodic months (≈ 10,571.95 days, or 29 years minus 20 days). Their appearance and longitude are irregular due to a lack of synchronization with the anomalistic month (period of perigee). However, groupings of 3 inex cycles (≈ 87 years minus 2 months) comes close (≈ 1,151.02 anomalistic months), so eclipses are similar in these groupings.
| Series members between 1801 and 2200 | |||||
|---|---|---|---|---|---|
| 1823 Jul 23 (Saros 126) |
1852 Jul 01 (Saros 127) |
1881 Jun 12 (Saros 128) | |||
| 1910 May 24 (Saros 129) |
1939 May 03 (Saros 130) |
1968 Apr 13 (Saros 131) | |||
| File:Lunar eclipse chart close-1910May24.png | File:Lunar eclipse from moon-1910May24.png | File:Lunar eclipse chart close-1939May03.png | File:Lunar eclipse from moon-1939May03.png | File:Lunar eclipse chart close-1968Apr13.png | File:Lunar eclipse from moon-1968Apr13.png |
| 1997 Mar 24 (Saros 132) |
2026 Mar 03 (Saros 133) |
2055 Feb 11 (Saros 134) | |||
| File:Lunar eclipse chart close-1997Mar24.png | File:Lunar eclipse from moon-1997Mar24.png | File:Lunar eclipse chart close-2026Mar03.png | File:Lunar eclipse from moon-2026Mar03.png | File:Lunar eclipse chart close-2055Feb11.png | File:Lunar eclipse from moon-2055Feb11.png |
| 2084 Jan 22 (Saros 135) |
2113 Jan 02 (Saros 136) |
2141 Dec 13 (Saros 137) | |||
| File:Lunar eclipse chart close-2084Jan22.png | File:Lunar eclipse from moon-2084Jan22.png | ||||
| 2170 Nov 23 (Saros 138) |
2199 Nov 02 (Saros 139) | ||||
Half-Saros cycle
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 annular solar eclipses of Solar Saros 138.
| April 8, 1959 | April 18, 1977 |
|---|---|
| File:SE1959Apr08A.png | File:SE1977Apr18A.png |
See also
Notes
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- ↑ Listing of Eclipses of series 131
- ↑ Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros
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External links
- 1968 Apr 13 chart Eclipse Predictions by Fred Espenak, NASA/GSFC
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