| Penumbral eclipse | |||||||||
 The Moon's hourly motion shown right to left | |||||||||
| Date | August 27, 1969 | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Gamma | −1.5407 | ||||||||
| Magnitude | −0.9514 | ||||||||
| Saros cycle | 108 (72 of 72) | ||||||||
| Penumbral | 31 minutes, 16 seconds | ||||||||
| |||||||||
A penumbrallunar eclipse occurred at the Moon’sascending node of orbit on Wednesday, August 27, 1969,[1] with an umbralmagnitude of −0.9514. 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 2.25 days afterperigee (on August 25, 1969, at 16:30 UTC), the Moon's apparent diameter was larger.[2]
This was the last lunar eclipse ofLunar Saros 108.
The eclipse was completely visible overeast andnortheast Asia,Australia, western and centralNorth America, westernSouth America, andAntarctica.[3]
 |
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 | 0.01337 |
| Umbral Magnitude | −0.95141 |
| Gamma | −1.54066 |
| Sun Right Ascension | 10h23m30.2s |
| Sun Declination | +10°03'05.7" |
| Sun Semi-Diameter | 15'50.0" |
| Sun Equatorial Horizontal Parallax | 08.7" |
| Moon Right Ascension | 22h26m20.1s |
| Moon Declination | -11°25'58.1" |
| Moon Semi-Diameter | 16'24.7" |
| Moon Equatorial Horizontal Parallax | 1°00'13.8" |
| ΔT | 39.8 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.
| August 27 Ascending node (full moon) | September 11 Descending node (new moon) | September 25 Ascending node (full moon) |
|---|---|---|
|  |  |
| Penumbral lunar eclipse Lunar Saros 108 | Annular solar eclipse Solar Saros 134 | Penumbral lunar eclipse Lunar Saros 146 |
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 onApril 2, 1969 andSeptember 25, 1969 occur in the previous lunar year eclipse set, and the lunar eclipses onJune 15, 1973 (penumbral) andDecember 10, 1973 (partial) occur in the next lunar year eclipse set.
| Lunar eclipse series sets from 1969 to 1973 | ||||||||
|---|---|---|---|---|---|---|---|---|
| Ascending node | Descending node | |||||||
| Saros | Date Viewing | Type Chart | Gamma | Saros | Date Viewing | Type Chart | Gamma | |
| 108 | 1969 Aug 27 | Penumbral | −1.5407 | 113 | 1970 Feb 21 | Partial | 0.9620 | |
| 118 | 1970 Aug 17 | Partial | −0.8053 | 123 | 1971 Feb 10 | Total | 0.2741 | |
| 128 | 1971 Aug 06 | Total | −0.0794 | 133 | 1972 Jan 30 | Total | −0.4273 | |
| 138 | 1972 Jul 26 | Partial | 0.7117 | 143 | 1973 Jan 18 | Penumbral | −1.0845 | |
| 148 | 1973 Jul 15 | Penumbral | 1.5178 | |||||
This eclipse is a part ofSaros series 108, repeating every 18 years, 11 days, and containing 72 events. The series started with a penumbral lunar eclipse on July 8, 689 AD. It contains partial eclipses from February 9, 1050 through May 17, 1212; total eclipses from May 28, 1230 through September 23, 1428; and a second set of partial eclipses from October 5, 1446 through June 1, 1825. The series ends at member 72 as a penumbral eclipse onAugust 27, 1969.
The longest duration of totality was produced by member 35 at 105 minutes, 57 seconds on July 10, 1302. All eclipses in this series occur at the Moon’sascending node of orbit.[6]
| Greatest | First | |||
|---|---|---|---|---|
| The greatest eclipse of the series occurred on1302 Jul 10, lasting 105 minutes, 57 seconds.[7] | Penumbral | Partial | Total | Central |
| 689 Jul 08 | 1050 Feb 09 | 1230 May 28 | 1266 Jun 19 | |
| Last | ||||
| Central | Total | Partial | Penumbral | |
| 1374 Aug 22 | 1428 Sep 23 | 1825 Jun 01 | 1969 Aug 27 | |
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 63–72 occur between 1801 and 1969: | |||||
|---|---|---|---|---|---|
| 63 | 64 | 65 | |||
| 1807 May 21 | 1825 Jun 01 | 1843 Jun 12 | |||
| 66 | 67 | 68 | |||
| 1861 Jun 22 | 1879 Jul 03 | 1897 Jul 14 | |||
| 69 | 70 | 71 | |||
| 1915 Jul 26 | 1933 Aug 05 | 1951 Aug 17 | |||
 |  |  |  |  |  |
| 72 | |||||
| 1969 Aug 27 | |||||
| | ||||
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 1904 and 2200 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 1904 Mar 02 (Saros 102) | 1915 Jan 31 (Saros 103) | ||||||||
 |  |  |  | ||||||
| 1969 Aug 27 (Saros 108) | 1980 Jul 27 (Saros 109) | 1991 Jun 27 (Saros 110) | 2002 May 26 (Saros 111) | ||||||
| |  |  |  |  |  |  | ||
| 2013 Apr 25 (Saros 112) | 2024 Mar 25 (Saros 113) | 2035 Feb 22 (Saros 114) | 2046 Jan 22 (Saros 115) | 2056 Dec 22 (Saros 116) | |||||
 |  |  |  |  |  |  |  |  |  |
| 2067 Nov 21 (Saros 117) | 2078 Oct 21 (Saros 118) | 2089 Sep 19 (Saros 119) | 2100 Aug 19 (Saros 120) | 2111 Jul 21 (Saros 121) | |||||
 |  | ||||||||
| 2122 Jun 20 (Saros 122) | 2133 May 19 (Saros 123) | 2144 Apr 18 (Saros 124) | 2155 Mar 19 (Saros 125) | 2166 Feb 15 (Saros 126) | |||||
| 2177 Jan 14 (Saros 127) | 2187 Dec 15 (Saros 128) | 2198 Nov 13 (Saros 129) | |||||||
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 | |||||
|---|---|---|---|---|---|
| 1824 Dec 06 (Saros 103) | |||||
| 1969 Aug 27 (Saros 108) | |||||
| | ||||
| 1998 Aug 08 (Saros 109) | 2027 Jul 18 (Saros 110) | 2056 Jun 27 (Saros 111) | |||
 |  |  |  |  |  |
| 2085 Jun 08 (Saros 112) | 2114 May 19 (Saros 113) | 2143 Apr 29 (Saros 114) | |||
| 2172 Apr 09 (Saros 115) | |||||
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