| Penumbral eclipse | |||||||||
 The Moon's hourly motion shown right to left | |||||||||
| Date | August 26, 1980 | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Gamma | −1.1608 | ||||||||
| Magnitude | −0.2531 | ||||||||
| Saros cycle | 147 (7 of 71) | ||||||||
| Penumbral | 214 minutes, 21 seconds | ||||||||
| |||||||||
A penumbrallunar eclipse occurred at the Moon’sdescending node of orbit on Tuesday, August 26, 1980,[1] with an umbralmagnitude of −0.2531. A lunar eclipse occurs when theMoon moves into theEarth'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 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 1.7 days beforeperigee (on August 27, 1980, at 20:05 UTC), the Moon's apparent diameter was larger.[2]
The eclipse was completely visible over central and easternNorth America,South America, andwest Africa, seen rising over western North America and the centralPacific Ocean and setting overcentral andeastern Africa,Europe, and theMiddle East.[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 | 0.70891 |
| Umbral Magnitude | −0.25310 |
| Gamma | −1.16082 |
| Sun Right Ascension | 10h19m57.4s |
| Sun Declination | +10°23'14.8" |
| Sun Semi-Diameter | 15'49.7" |
| Sun Equatorial Horizontal Parallax | 08.7" |
| Moon Right Ascension | 22h21m14.5s |
| Moon Declination | -11°30'44.4" |
| Moon Semi-Diameter | 16'27.2" |
| Moon Equatorial Horizontal Parallax | 1°00'23.3" |
| ΔT | 51.1 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. The first and last eclipse in this sequence is separated by onesynodic month.
| July 27 Descending node (full moon) | August 10 Ascending node (new moon) | August 26 Descending node (full moon) |
|---|---|---|
 |  | |
| Penumbral lunar eclipse Lunar Saros 109 | Annular solar eclipse Solar Saros 135 | Penumbral lunar eclipse Lunar Saros 147 |
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 eclipse onJuly 27, 1980 occurs in the next lunar year eclipse set.
| Lunar eclipse series sets from 1977 to 1980 | ||||||||
|---|---|---|---|---|---|---|---|---|
| Ascending node | Descending node | |||||||
| Saros | Date Viewing | Type Chart | Gamma | Saros | Date Viewing | Type Chart | Gamma | |
| 112 | 1977 Apr 04 | Partial | −0.9148 | 117 | 1977 Sep 27 | Penumbral | 1.0768 | |
| 122 | 1978 Mar 24 | Total | −0.2140 | 127 | 1978 Sep 16 | Total | 0.2951 | |
| 132 | 1979 Mar 13 | Partial | 0.5254 | 137 | 1979 Sep 06 | Total | −0.4305 | |
| 142 | 1980 Mar 01 | Penumbral | 1.2270 | 147 | 1980 Aug 26 | Penumbral | −1.1608 | |
This eclipse is a part ofSaros series 147, repeating every 18 years, 11 days, and containing 70 events. The series started with a penumbral lunar eclipse on July 2, 1890. It contains partial eclipses fromSeptember 28, 2034 through May 27, 2431; total eclipses from June 6, 2449 through October 5, 2647; and a second set of partial eclipses from October 16, 2665 through May 1, 2990. The series ends at member 70 as a penumbral eclipse on July 28, 3145.
The longest duration of totality will be produced by member 37 at 105 minutes, 18 seconds on August 1, 2539. All eclipses in this series occur at the Moon’sdescending node of orbit.[6]
| Greatest | First | |||
|---|---|---|---|---|
| The greatest eclipse of the series will occur on2539 Aug 01, lasting 105 minutes, 18 seconds.[7] | Penumbral | Partial | Total | Central |
| 1890 Jul 02 | 2034 Sep 28 | 2449 Jun 06 | 2485 Jun 28 | |
| Last | ||||
| Central | Total | Partial | Penumbral | |
| 2593 Sep 02 | 2647 Oct 05 | 2990 May 01 | 3134 Jul 28 | |
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 1–18 occur between 1890 and 2200: | |||||
|---|---|---|---|---|---|
| 1 | 2 | 3 | |||
| 1890 Jul 02 | 1908 Jul 13 | 1926 Jul 25 | |||
 |  |  |  | ||
| 4 | 5 | 6 | |||
| 1944 Aug 04 | 1962 Aug 15 | 1980 Aug 26 | |||
 |  |  |  | | |
| 7 | 8 | 9 | |||
| 1998 Sep 06 | 2016 Sep 16 | 2034 Sep 28 | |||
 |  |  |  | |  |
| 10 | 11 | 12 | |||
| 2052 Oct 08 | 2070 Oct 19 | 2088 Oct 30 | |||
 |  |  |  | ||
| 13 | 14 | 15 | |||
| 2106 Nov 11 | 2124 Nov 21 | 2142 Dec 03 | |||
| 16 | 17 | 18 | |||
| 2160 Dec 13 | 2178 Dec 24 | 2197 Jan 04 | |||
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 2078 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 1806 Jan 05 (Saros 131) | 1816 Dec 04 (Saros 132) | 1827 Nov 03 (Saros 133) | 1838 Oct 03 (Saros 134) | 1849 Sep 02 (Saros 135) | |||||
| 1860 Aug 01 (Saros 136) | 1871 Jul 02 (Saros 137) | 1882 Jun 01 (Saros 138) | 1893 Apr 30 (Saros 139) | 1904 Mar 31 (Saros 140) | |||||
 |  | ||||||||
| 1915 Mar 01 (Saros 141) | 1926 Jan 28 (Saros 142) | 1936 Dec 28 (Saros 143) | 1947 Nov 28 (Saros 144) | 1958 Oct 27 (Saros 145) | |||||
 |  |  |  |  |  |  |  |  |  |
| 1969 Sep 25 (Saros 146) | 1980 Aug 26 (Saros 147) | 1991 Jul 26 (Saros 148) | 2002 Jun 24 (Saros 149) | 2013 May 25 (Saros 150) | |||||
 |  | | |  |  |  |  |  |  |
| 2078 Nov 19 (Saros 156) | |||||||||
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 2154 | |||||
|---|---|---|---|---|---|
| 1806 Dec 25 (Saros 141) | 1835 Dec 05 (Saros 142) | 1864 Nov 13 (Saros 143) | |||
| 1893 Oct 25 (Saros 144) | 1922 Oct 06 (Saros 145) | 1951 Sep 15 (Saros 146) | |||
 |  |  |  | ||
| 1980 Aug 26 (Saros 147) | 2009 Aug 06 (Saros 148) | 2038 Jul 16 (Saros 149) | |||
| |  |  |  |  |
| 2067 Jun 27 (Saros 150) | 2096 Jun 06 (Saros 151) | 2125 May 17 (Saros 152) | |||
| 2154 Apr 28 (Saros 153) | |||||
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 154.
| August 20, 1971 | August 31, 1989 |
|---|---|
 |  |
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