| Total eclipse | |
 Totality photographed by Morton's party in Iowa | |
 Map | |
| Gamma | 0.696 |
|---|---|
| Magnitude | 1.0551 |
| Maximum eclipse | |
| Duration | 228 s (3 min 48 s) |
| Coordinates | 59°06′N133°12′W / 59.1°N 133.2°W /59.1; -133.2 |
| Max. width of band | 254 km (158 mi) |
| Times (UTC) | |
| Greatest eclipse | 22:01:05 |
| References | |
| Saros | 143 (15 of 72) |
| Catalog # (SE5000) | 9209 |
← February 11, 1869 | |
A totalsolar eclipse occurred at the Moon'sascending node of orbit between Saturday, August 7, and Sunday, August 8, 1869, with amagnitude of 1.0551. Asolar eclipse occurs when theMoon passes betweenEarth and theSun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. A total solar eclipse occurs when the Moon'sapparent diameter is larger than the Sun's, blocking all direct sunlight, turning day into darkness. Totality occurs in a narrow path across Earth's surface, with the partial solar eclipse visible over a surrounding region thousands of kilometres wide. Occurring about 1.6 days beforeperigee (on August 9, 1869, at 13:20 UTC), the Moon's apparent diameter was larger.[1]
The path of totality was visible from parts of modern-day easternRussia,Alaska, westernCanada,Montana,North Dakota,South Dakota,Minnesota,Nebraska,Iowa,Missouri,Illinois,Indiana,Kentucky,Tennessee,West Virginia,Virginia,North Carolina, andSouth Carolina. A partial solar eclipse was also visible for parts ofNortheast Asia,North America,Central America, and theCaribbean.
This eclipse was the first major eclipse photographed and also included many different scientific expeditions to view it across totality.
Maria Mitchell took a group ofVassar College students to view the eclipse with telescopes inBurlington, Iowa.[2]
In 1869, astronomer and explorerGeorge Davidson made a scientific trip to theChilkat Valley of Alaska. He told the Chilkat Indians that he was anxious to observe a total eclipse of the Sun that was predicted to occur the following day, August 7. This prediction was considered to have saved Davidson's expedition from an attack.[3]
A photographic expedition was organized by Philadelphia'sHenry Morton under the authority ofJohn H. C. Coffin, U.S.N., Superintendent of theAmerican Ephemeris and Nautical Almanac. The expedition observed the eclipse in Iowa at three stations:Burlington,Mount Pleasant, andOttumwa, under the respective supervisions ofAlfred M. Mayer, Henry Morton, andCharles Francis Himes (1838–1918).[4]
Observations were also made by meteorology pioneersCleveland Abbe andGeneral Albert Myer, inDakota Territory andVirginia, respectively.[5]
Shown below are two tables displaying details about this particular solar eclipse. The first table outlines times at which the Moon's penumbra or umbra attains the specific parameter, and the second table describes various other parameters pertaining to this eclipse.[6]
| Event | Time (UTC) |
|---|---|
| First Penumbral External Contact | 1869 August 7 at 19:38:08.9 UTC |
| First Umbral External Contact | 1869 August 7 at 20:44:43.8 UTC |
| First Central Line | 1869 August 7 at 20:46:19.1 UTC |
| First Umbral Internal Contact | 1869 August 7 at 20:47:55.4 UTC |
| Equatorial Conjunction | 1869 August 7 at 21:46:10.8 UTC |
| Greatest Duration | 1869 August 7 at 22:00:53.7 UTC |
| Greatest Eclipse | 1869 August 7 at 22:01:04.7 UTC |
| Ecliptic Conjunction | 1869 August 7 at 22:08:11.2 UTC |
| Last Umbral Internal Contact | 1869 August 7 at 23:14:22.8 UTC |
| Last Central Line | 1869 August 7 at 23:16:00.7 UTC |
| Last Umbral External Contact | 1869 August 7 at 23:17:37.6 UTC |
| Last Penumbral External Contact | 1869 August 8 at 00:24:03.9 UTC |
| Parameter | Value |
|---|---|
| Eclipse Magnitude | 1.05514 |
| Eclipse Obscuration | 1.11332 |
| Gamma | 0.69599 |
| Sun Right Ascension | 09h11m15.8s |
| Sun Declination | +16°14'37.3" |
| Sun Semi-Diameter | 15'46.6" |
| Sun Equatorial Horizontal Parallax | 08.7" |
| Moon Right Ascension | 09h11m50.9s |
| Moon Declination | +16°55'41.0" |
| Moon Semi-Diameter | 16'27.0" |
| Moon Equatorial Horizontal Parallax | 1°00'22.4" |
| ΔT | 1.2 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.
| July 23 Descending node (full moon) | August 7 Ascending node (new moon) |
|---|---|
| |
| Partial lunar eclipse Lunar Saros 117 | Total solar eclipse Solar Saros 143 |
This eclipse is a member of asemester series. An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternatingnodes of the Moon's orbit.[7]
The partial solar eclipses on April 15, 1866 and October 8, 1866 occur in the previous lunar year eclipse set, and the solar eclipses on June 28, 1870 (partial) andDecember 22, 1870 (total) occur in the next lunar year eclipse set.
| Solar eclipse series sets from 1866 to 1870 | ||||||
|---|---|---|---|---|---|---|
| Descending node | Ascending node | |||||
| Saros | Map | Gamma | Saros | Map | Gamma | |
| 108 | March 16, 1866 Partial | 1.4241 | 113 | |||
| 118 | March 6, 1867 Annular | 0.7716 | 123 | August 29, 1867 Total | −0.7940 | |
| 128 | February 23, 1868 Annular | 0.0706 | 133 | August 18, 1868 Total | −0.0443 | |
| 138 | February 11, 1869 Annular | −0.6251 | 143 | August 7, 1869 Total | 0.6960 | |
| 148 | January 31, 1870 Partial | −1.2829 | 153 | July 28, 1870 Partial | 1.5044 | |
This eclipse is a part ofSaros series 143, repeating every 18 years, 11 days, and containing 72 events. The series started with a partial solar eclipse on March 7, 1617. It contains total eclipses from June 24, 1797 throughOctober 24, 1995; hybrid eclipses fromNovember 3, 2013 throughDecember 6, 2067; and annular eclipses fromDecember 16, 2085 through September 16, 2536. The series ends at member 72 as a partial eclipse on April 23, 2897. Its 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.
The longest duration of totality was produced by member 16 at 3 minutes, 50 seconds onAugust 19, 1887, and the longest duration of annularity will be produced by member 51 at 4 minutes, 54 seconds on September 6, 2518. All eclipses in this series occur at the Moon’sascending node of orbit.[8]
| Series members 12–33 occur between 1801 and 2200: | ||
|---|---|---|
| 12 | 13 | 14 |
 July 6, 1815 |  July 17, 1833 |  July 28, 1851 |
| 15 | 16 | 17 |
August 7, 1869 |  August 19, 1887 |  August 30, 1905 |
| 18 | 19 | 20 |
 September 10, 1923 |  September 21, 1941 |  October 2, 1959 |
| 21 | 22 | 23 |
 October 12, 1977 |  October 24, 1995 |  November 3, 2013 |
| 24 | 25 | 26 |
 November 14, 2031 |  November 25, 2049 |  December 6, 2067 |
| 27 | 28 | 29 |
 December 16, 2085 |  December 29, 2103 |  January 8, 2122 |
| 30 | 31 | 32 |
 January 20, 2140 |  January 30, 2158 |  February 10, 2176 |
| 33 | ||
 February 21, 2194 | ||
Themetonic series repeats eclipses every 19 years (6939.69 days), lasting about 5 cycles. Eclipses occur in nearly the same calendar date. In addition, the octon subseries repeats 1/5 of that or every 3.8 years (1387.94 days). All eclipses in this table occur at the Moon's ascending node.
| 25 eclipse events between March 14, 1801 and August 7, 1888 | ||||
|---|---|---|---|---|
| March 14–15 | December 31–January 1 | October 19–20 | August 7 | May 26–27 |
| 107 | 109 | 111 | 113 | 115 |
 March 14, 1801 |  January 1, 1805 |  October 19, 1808 |  August 7, 1812 |  May 27, 1816 |
| 117 | 119 | 121 | 123 | 125 |
 March 14, 1820 |  January 1, 1824 |  October 20, 1827 |  August 7, 1831 |  May 27, 1835 |
| 127 | 129 | 131 | 133 | 135 |
 March 15, 1839 |  December 31, 1842 |  October 20, 1846 |  August 7, 1850 |  May 26, 1854 |
| 137 | 139 | 141 | 143 | 145 |
 March 15, 1858 |  December 31, 1861 |  October 19, 1865 | August 7, 1869 |  May 26, 1873 |
| 147 | 149 | 151 | 153 | |
 March 15, 1877 |  December 31, 1880 |  October 19, 1884 |  August 7, 1888 | |
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.
The partial solar eclipse onOctober 24, 2098 (part of Saros 164) is also a part of this series but is not included in the table below.
| Series members between 1801 and 2011 | ||||
|---|---|---|---|---|
 February 11, 1804 (Saros 137) |  January 10, 1815 (Saros 138) |  December 9, 1825 (Saros 139) |  November 9, 1836 (Saros 140) |  October 9, 1847 (Saros 141) |
 September 7, 1858 (Saros 142) | August 7, 1869 (Saros 143) |  July 7, 1880 (Saros 144) |  June 6, 1891 (Saros 145) |  May 7, 1902 (Saros 146) |
 April 6, 1913 (Saros 147) |  March 5, 1924 (Saros 148) |  February 3, 1935 (Saros 149) |  January 3, 1946 (Saros 150) |  December 2, 1956 (Saros 151) |
 November 2, 1967 (Saros 152) |  October 2, 1978 (Saros 153) |  August 31, 1989 (Saros 154) |  July 31, 2000 (Saros 155) |  July 1, 2011 (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 2200 | ||
|---|---|---|
 September 17, 1811 (Saros 141) |  August 27, 1840 (Saros 142) | August 7, 1869 (Saros 143) |
 July 18, 1898 (Saros 144) |  June 29, 1927 (Saros 145) |  June 8, 1956 (Saros 146) |
 May 19, 1985 (Saros 147) |  April 29, 2014 (Saros 148) |  April 9, 2043 (Saros 149) |
 March 19, 2072 (Saros 150) |  February 28, 2101 (Saros 151) |  February 8, 2130 (Saros 152) |
 January 19, 2159 (Saros 153) |  December 29, 2187 (Saros 154) | |
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