A total solar eclipse occurred at the Moon's descending node of orbit between Monday, July 29, and Tuesday, July 30, 1878, with a magnitude of 1.0450. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. A total solar eclipse occurs when the Moon's apparent 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 2.4 days before perigee (on August 1, 1878, at 6:45 UTC), the Moon's apparent diameter was larger.
The path of totality was visible from parts of modern-day eastern Russia, Alaska, western Canada, Washington, Idaho, Montana, Wyoming, Colorado, New Mexico, Kansas, Oklahoma, Texas, Louisiana, Cuba, Haiti, and the Dominican Republic. A partial solar eclipse was also visible for parts of Northeast Asia, North America, Central America, the Caribbean, and northern South America.
Newspapers in the United States reported of large migrations from the Midwest towards the path of totality to view the eclipse. Scientists observing from Pikes Peak in Colorado contended with altitude sickness and snowstorms, among other problems.
High-altitude astronomy
The 1878 eclipse was a turning point in modern astronomy, because it was the first time that many of the world's leading astronomers had the opportunity to make their observations from the higher altitudes provided by the Rocky Mountains. After the 1878 eclipse, astronomers began to build observatories at locations well above sea level, including on the sides and summits of mountains, a scientific trend which extended throughout the twentieth century and into the twenty-first.
Eclipse details
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.
Eclipse season
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.
Eclipses in 1878
- An annular solar eclipse on February 2.
- A partial lunar eclipse on February 17.
- A total solar eclipse on July 29.
- A partial lunar eclipse on August 13.
Metonic
- Preceded by: Solar eclipse of October 10, 1874
- Followed by: Solar eclipse of May 17, 1882
Tzolkinex
- Preceded by: Solar eclipse of June 18, 1871
- Followed by: Solar eclipse of September 8, 1885
Half-Saros
- Preceded by: Lunar eclipse of July 23, 1869
- Followed by: Lunar eclipse of August 3, 1887
Tritos
- Preceded by: Solar eclipse of August 29, 1867
- Followed by: Solar eclipse of June 28, 1889
Solar Saros 124
- Preceded by: Solar eclipse of July 18, 1860
- Followed by: Solar eclipse of August 9, 1896
Inex
- Preceded by: Solar eclipse of August 18, 1849
- Followed by: Solar eclipse of July 10, 1907
Triad
- Preceded by: Solar eclipse of September 27, 1791
- Followed by: Solar eclipse of May 30, 1965
Solar eclipses of 1877–1880
This eclipse is a member of a semester series. An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternating nodes of the Moon's orbit.
The partial solar eclipses on March 15, 1877 and September 7, 1877 occur in the previous lunar year eclipse set, and the partial solar eclipse on December 2, 1880 occurs in the next lunar year eclipse set.
Saros 124
This eclipse is a part of Saros series 124, repeating every 18 years, 11 days, and containing 73 events. The series started with a partial solar eclipse on March 6, 1049. It contains total eclipses from June 12, 1211 through September 22, 1968, and a hybrid eclipse on October 3, 1986. There are no annular eclipses in this set. The series ends at member 73 as a partial eclipse on May 11, 2347. Its 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.
The longest duration of totality was produced by member 39 at 5 minutes, 46 seconds on May 3, 1734. All eclipses in this series occur at the Moon’s descending node of orbit.
Metonic series
The metonic 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 descending node.
Tritos series
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
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.