October 1968 lunar eclipse
| Total eclipse | |||||||||||||||||
| File:Lunar eclipse chart close-1968Oct06.png The Moon's hourly motion shown right to left | |||||||||||||||||
| Date | October 6, 1968 | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Gamma | 0.3605 | ||||||||||||||||
| Magnitude | 1.1691 | ||||||||||||||||
| Saros cycle | 136 (17 of 72) | ||||||||||||||||
| Totality | 62 minutes, 58 seconds | ||||||||||||||||
| Partiality | 213 minutes, 56 seconds | ||||||||||||||||
| Penumbral | 352 minutes, 2 seconds | ||||||||||||||||
| |||||||||||||||||
A total lunar eclipse occurred at the Moon’s ascending node of orbit on Sunday, October 6, 1968,[1] with an umbral magnitude of 1.1691. 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 5.3 days before apogee (on October 11, 1968, at 18:05 UTC), the Moon's apparent diameter was smaller.[2]
This lunar eclipse was the last of a tetrad, with four total lunar eclipses in series, the others being on April 24, 1967; October 18, 1967; and April 13, 1968.
Visibility
[edit | edit source]The eclipse was completely visible over northeast Asia, eastern Australia, northwestern North America and much of the Pacific Ocean, seen rising over most of Asia and western Australia and setting over North and South America.[3]
| File:Lunar eclipse from moon-1968Oct06.png File:Lunar eclipse chart close-1968Oct06.png |
Eclipse details
[edit | edit source]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 | 2.22423 |
| Umbral Magnitude | 1.16913 |
| Gamma | 0.36054 |
| Sun Right Ascension | 12h48m51.9s |
| Sun Declination | -05°14'36.0" |
| Sun Semi-Diameter | 16'00.2" |
| Sun Equatorial Horizontal Parallax | 08.8" |
| Moon Right Ascension | 00h48m13.3s |
| Moon Declination | +05°32'13.0" |
| Moon Semi-Diameter | 15'10.1" |
| Moon Equatorial Horizontal Parallax | 0°55'39.9" |
| ΔT | 39.0 s |
Eclipse season
[edit | edit source]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.
| September 22 Descending node (new moon) |
October 6 Ascending node (full moon) |
|---|---|
| File:SE1968Sep22T.png | File:Lunar eclipse chart close-1968Oct06.png |
| Total solar eclipse Solar Saros 124 |
Total lunar eclipse Lunar Saros 136 |
Related eclipses
[edit | edit source]Eclipses in 1968
[edit | edit source]- 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
[edit | edit source]- Preceded by: Lunar eclipse of December 19, 1964
- Followed by: Lunar eclipse of July 26, 1972
Tzolkinex
[edit | edit source]- Preceded by: Lunar eclipse of August 26, 1961
- Followed by: Lunar eclipse of November 18, 1975
Half-Saros
[edit | edit source]- Preceded by: Solar eclipse of October 2, 1959
- Followed by: Solar eclipse of October 12, 1977
Tritos
[edit | edit source]- Preceded by: Lunar eclipse of November 7, 1957
- Followed by: Lunar eclipse of September 6, 1979
Lunar Saros 136
[edit | edit source]- Preceded by: Lunar eclipse of September 26, 1950
- Followed by: Lunar eclipse of October 17, 1986
Inex
[edit | edit source]- Preceded by: Lunar eclipse of October 28, 1939
- Followed by: Lunar eclipse of September 16, 1997
Triad
[edit | edit source]- Preceded by: Lunar eclipse of December 5, 1881
- Followed by: Lunar eclipse of August 7, 2055
Lunar eclipses of 1966–1969
[edit | edit source]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 136
[edit | edit source]This eclipse is a part of Saros series 136, repeating every 18 years, 11 days, and containing 72 events. The series started with a penumbral lunar eclipse on April 13, 1680. It contains partial eclipses from July 11, 1824 through September 14, 1932; total eclipses from September 26, 1950 through July 7, 2419; and a second set of partial eclipses from July 18, 2437 through October 3, 2563. The series ends at member 72 as a penumbral eclipse on June 1, 2960.
The longest duration of totality will be produced by member 35 at 101 minutes, 23 seconds on April 21, 2293. All eclipses in this series occur at the Moon’s ascending node of orbit.[6]
| Greatest | First | |||
|---|---|---|---|---|
| The greatest eclipse of the series will occur on 2293 Apr 21, lasting 101 minutes, 23 seconds.[7] | Penumbral | Partial | Total | Central |
| 1680 Apr 13 |
1824 Jul 11 |
1950 Sep 26 File:Lunar eclipse chart close-1950Sep26.png |
2022 Nov 08 File:Lunar eclipse chart close-2022nov08.png | |
| Last | ||||
| Central | Total | Partial | Penumbral | |
| 2365 Jun 04 |
2419 Jul 07 |
2563 Oct 03 |
2960 Jun 01 | |
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
[edit | edit source]This eclipse is a part of a tritos cycle, repeating at alternating nodes every 135 synodic months (≈ 3986.63 days, or 11 years minus 1 month). Their appearance and longitude are irregular due to a lack of synchronization with the anomalistic month (period of perigee), but groupings of 3 tritos cycles (≈ 33 years minus 3 months) come close (≈ 434.044 anomalistic months), so eclipses are similar in these groupings.
Inex series
[edit | edit source]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 | |||||
|---|---|---|---|---|---|
| 1824 Jan 16 (Saros 131) |
1852 Dec 26 (Saros 132) |
1881 Dec 05 (Saros 133) | |||
| 1910 Nov 17 (Saros 134) |
1939 Oct 28 (Saros 135) |
1968 Oct 06 (Saros 136) | |||
| File:Lunar eclipse chart close-1910Nov17.png | File:Lunar eclipse from moon-1910Nov17.png | File:Lunar eclipse chart close-1939Oct28.png | File:Lunar eclipse from moon-1939Oct28.png | File:Lunar eclipse chart close-1968Oct06.png | File:Lunar eclipse from moon-1968Oct06.png |
| 1997 Sep 16 (Saros 137) |
2026 Aug 28 (Saros 138) |
2055 Aug 07 (Saros 139) | |||
| File:Lunar eclipse chart close-1997Sep16.png | File:Lunar eclipse from moon-1997Sep16.png | File:Lunar eclipse chart close-2026Aug28.png | File:Lunar eclipse from moon-2026Aug28.png | File:Lunar eclipse chart close-2055Aug07.png | File:Lunar eclipse from moon-2055Aug07.png |
| 2084 Jul 17 (Saros 140) |
2113 Jun 29 (Saros 141) |
2142 Jun 08 (Saros 142) | |||
| 2171 May 19 (Saros 143) |
2200 Apr 30 (Saros 144) | ||||
Half-Saros cycle
[edit | edit source]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 total solar eclipses of Solar Saros 143.
| October 2, 1959 | October 12, 1977 |
|---|---|
| File:SE1959Oct02T.png | File:SE1977Oct12T.png |
See also
[edit | edit source]Notes
[edit | edit source]- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Listing of Eclipses of series 136
- ^ Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros
External links
[edit | edit source]- 1968 Oct 06 chart Eclipse Predictions by Fred Espenak, NASA/GSFC
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