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.[1]
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.[2] [3]
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.[4]
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.[5]
| First Penumbral External Contact | 1878 July 29 at 19:18:31.9 UTC | |
| First Umbral External Contact | 1878 July 29 at 20:23:40.9 UTC | |
| First Central Line | 1878 July 29 at 20:24:46.4 UTC | |
| First Umbral Internal Contact | 1878 July 29 at 20:25:52.4 UTC | |
| Equatorial Conjunction | 1878 July 29 at 21:23:06.4 UTC | |
| Ecliptic Conjunction | 1878 July 29 at 21:40:46.5 UTC | |
| Greatest Duration | 1878 July 29 at 21:46:11.9 UTC | |
| Greatest Eclipse | 1878 July 29 at 21:47:17.7 UTC | |
| Last Umbral Internal Contact | 1878 July 29 at 23:08:56.0 UTC | |
| Last Central Line | 1878 July 29 at 23:10:04.0 UTC | |
| Last Umbral External Contact | 1878 July 29 at 23:11:11.6 UTC | |
| Last Penumbral External Contact | 1878 July 30 at 00:16:08.9 UTC |
| Eclipse Magnitude | 1.04495 | |
| Eclipse Obscuration | 1.09192 | |
| Gamma | 0.62323 | |
| Sun Right Ascension | 08h35m50.0s | |
| Sun Declination | +18°38'42.9" | |
| Sun Semi-Diameter | 15'45.4" | |
| Sun Equatorial Horizontal Parallax | 08.7" | |
| Moon Right Ascension | 08h36m44.1s | |
| Moon Declination | +19°13'31.6" | |
| Moon Semi-Diameter | 16'15.3" | |
| Moon Equatorial Horizontal Parallax | 0°59'39.2" | |
| ΔT | -4.7 s |
See also: Eclipse cycle. 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.
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.
| Solar eclipse series sets from 1877 to 1880 | ||||||
|---|---|---|---|---|---|---|
| Descending node | Ascending node | |||||
| Saros | Map | Gamma | Saros | Map | Gamma | |
| 114 | August 9, 1877 Partial | 1.3277 | 119 | February 2, 1878 Annular | −0.9071 | |
| 124 | July 29, 1878 Total | 0.6232 | 129 | January 22, 1879 Annular | −0.1824 | |
| 134 | July 19, 1879 Annular | −0.1439 | 139 | January 11, 1880 Total | 0.6136 | |
| 144 | July 7, 1880 Annular | −0.9406 | 146 | December 31, 1880 Partial | 1.1591 | |
