| Partial eclipse | |||||||||||||
 The Moon's hourly motion shown right to left | |||||||||||||
| Date | May 13, 1976 | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Gamma | 0.9586 | ||||||||||||
| Magnitude | 0.1217 | ||||||||||||
| Saros cycle | 140 (23 of 80) | ||||||||||||
| Partiality | 75 minutes, 23 seconds | ||||||||||||
| Penumbral | 251 minutes, 49 seconds | ||||||||||||
| |||||||||||||
A partiallunar eclipse occurred at the Moon’sascending node of orbit on Thursday, May 13, 1976,[1] with an umbralmagnitude of 0.1217. A lunar eclipse occurs when theMoon moves into theEarth'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 asolar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on thenight side of Earth. Occurring about 1.1 days afterperigee (on May 12, 1976, at 17:30 UTC), the Moon's apparent diameter was larger.[2]
The eclipse was completely visible overcentral andeast Africa,eastern Europe, the western half ofAsia, westernAustralia, andAntarctica, seen rising over easternSouth America,west Africa, andwestern Europe and setting overeast andnortheast Asia and eastern Australia.[3]
 |
Shown below is a table displaying details about this particular lunar eclipse. It describes various parameters pertaining to this eclipse.[4]
| Parameter | Value |
|---|---|
| Penumbral Magnitude | 1.07612 |
| Umbral Magnitude | 0.12170 |
| Gamma | 0.95860 |
| Sun Right Ascension | 03h23m03.9s |
| Sun Declination | +18°33'49.8" |
| Sun Semi-Diameter | 15'49.5" |
| Sun Equatorial Horizontal Parallax | 08.7" |
| Moon Right Ascension | 15h23m42.3s |
| Moon Declination | -17°36'13.1" |
| Moon Semi-Diameter | 16'34.8" |
| Moon Equatorial Horizontal Parallax | 1°00'51.1" |
| ΔT | 46.9 s |
This eclipse is part of aneclipse 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 afortnight.
| April 29 Descending node (new moon) | May 13 Ascending node (full moon) |
|---|---|
 | |
| Annular solar eclipse Solar Saros 128 | Partial lunar eclipse Lunar Saros 140 |
This eclipse is a member of asemester series. An eclipse in a semester series of lunar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternatingnodes of the Moon's orbit.[5]
The penumbral lunar eclipses onJanuary 18, 1973 andJuly 15, 1973 occur in the previous lunar year eclipse set.
| Lunar eclipse series sets from 1973 to 1976 | ||||||||
|---|---|---|---|---|---|---|---|---|
| Ascending node | Descending node | |||||||
| Saros | Date Viewing | Type Chart | Gamma | Saros | Date Viewing | Type Chart | Gamma | |
| 110 | 1973 Jun 15 | Penumbral | −1.3217 | 115 | 1973 Dec 10 | Partial | 0.9644 | |
| 120 | 1974 Jun 04 | Partial | −0.5489 | 125 | 1974 Nov 29 | Total | 0.3054 | |
| 130 | 1975 May 25 | Total | 0.2367 | 135 | 1975 Nov 18 | Total | −0.4134 | |
| 140 | 1976 May 13 | Partial | 0.9586 | 145 | 1976 Nov 06 | Penumbral | −1.1276 | |
This eclipse is a part ofSaros series 140, repeating every 18 years, 11 days, and containing 77 events. The series started with a penumbral lunar eclipse on September 25, 1597. It contains partial eclipses fromMay 3, 1958 throughJuly 17, 2084; total eclipses from July 30, 2102 through May 21, 2589; and a second set of partial eclipses from June 2, 2607 through August 7, 2715. The series ends at member 77 as a penumbral eclipse on January 6, 2968.
The longest duration of totality will be produced by member 38 at 98 minutes, 36 seconds on November 4, 2264. All eclipses in this series occur at the Moon’sascending node of orbit.[6]
| Greatest | First | |||
|---|---|---|---|---|
| The greatest eclipse of the series will occur on2264 Nov 04, lasting 98 minutes, 36 seconds.[7] | Penumbral | Partial | Total | Central |
| 1597 Sep 25 | 1958 May 03 | 2102 Jul 30 | 2156 Aug 30 | |
| Last | ||||
| Central | Total | Partial | Penumbral | |
| 2535 Apr 19 | 2589 May 21 | 2715 Aug 07 | 2968 Jan 06 | |
Eclipses are tabulated in three columns; every third eclipse in the same column is oneexeligmos apart, so they all cast shadows over approximately the same parts of the Earth.
| Series members 13–34 occur between 1801 and 2200: | |||||
|---|---|---|---|---|---|
| 13 | 14 | 15 | |||
| 1814 Feb 04 | 1832 Feb 16 | 1850 Feb 26 | |||
| 16 | 17 | 18 | |||
| 1868 Mar 08 | 1886 Mar 20 | 1904 Mar 31 | |||
 |  | ||||
| 19 | 20 | 21 | |||
| 1922 Apr 11 | 1940 Apr 22 | 1958 May 03 | |||
 |  |  |  | |  |
| 22 | 23 | 24 | |||
| 1976 May 13 | 1994 May 25 | 2012 Jun 04 | |||
| |  |  |  |  |
| 25 | 26 | 27 | |||
| 2030 Jun 15 | 2048 Jun 26 | 2066 Jul 07 | |||
 |  |  |  | ||
| 28 | 29 | 30 | |||
| 2084 Jul 17 | 2102 Jul 30 | 2120 Aug 09 | |||
| 31 | 32 | 33 | |||
| 2138 Aug 20 | 2156 Aug 30 | 2174 Sep 11 | |||
| 34 | |||||
| 2192 Sep 21 | |||||
This eclipse is a part of atritos cycle, repeating at alternating nodes every 135synodic months (≈ 3986.63 days, or 11 years minus 1 month). Their appearance and longitude are irregular due to a lack of synchronization with theanomalistic 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.
| Series members between 1801 and 2183 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 1801 Sep 22 (Saros 124) | 1812 Aug 22 (Saros 125) | 1823 Jul 23 (Saros 126) | 1834 Jun 21 (Saros 127) | 1845 May 21 (Saros 128) | |||||
| 1856 Apr 20 (Saros 129) | 1867 Mar 20 (Saros 130) | 1878 Feb 17 (Saros 131) | 1889 Jan 17 (Saros 132) | 1899 Dec 17 (Saros 133) | |||||
| 1910 Nov 17 (Saros 134) | 1921 Oct 16 (Saros 135) | 1932 Sep 14 (Saros 136) | 1943 Aug 15 (Saros 137) | 1954 Jul 16 (Saros 138) | |||||
 |  |  |  |  |  |  |  |  |  |
| 1965 Jun 14 (Saros 139) | 1976 May 13 (Saros 140) | 1987 Apr 14 (Saros 141) | 1998 Mar 13 (Saros 142) | 2009 Feb 09 (Saros 143) | |||||
 |  | | |  |  |  |  |  |  |
| 2020 Jan 10 (Saros 144) | 2030 Dec 09 (Saros 145) | 2041 Nov 08 (Saros 146) | 2052 Oct 08 (Saros 147) | 2063 Sep 07 (Saros 148) | |||||
 |  |  |  |  |  |  |  | ||
| 2074 Aug 07 (Saros 149) | 2085 Jul 07 (Saros 150) | 2096 Jun 06 (Saros 151) | 2107 May 07 (Saros 152) | ||||||
| 2151 Jan 02 (Saros 156) | 2172 Oct 31 (Saros 158) | ||||||||
| 2183 Oct 01 (Saros 159) | |||||||||
This eclipse is a part of the long periodinex cycle, repeating at alternating nodes, every 358synodic months (≈ 10,571.95 days, or 29 years minus 20 days). Their appearance and longitude are irregular due to a lack of synchronization with theanomalistic 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 | |||||
|---|---|---|---|---|---|
| 1802 Sep 11 (Saros 134) | 1831 Aug 23 (Saros 135) | 1860 Aug 01 (Saros 136) | |||
| 1889 Jul 12 (Saros 137) | 1918 Jun 24 (Saros 138) | 1947 Jun 03 (Saros 139) | |||
 |  |  |  | ||
| 1976 May 13 (Saros 140) | 2005 Apr 24 (Saros 141) | 2034 Apr 03 (Saros 142) | |||
| |  |  |  |  |
| 2063 Mar 14 (Saros 143) | 2092 Feb 23 (Saros 144) | 2121 Feb 02 (Saros 145) | |||
| 2150 Jan 13 (Saros 146) | 2178 Dec 24 (Saros 147) | ||||
A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (ahalf saros).[8] This lunar eclipse is related to two partial solar eclipses ofSolar Saros 147.
| May 9, 1967 | May 19, 1985 |
|---|---|
 |  |
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