A total solar eclipse occurred at the Moon's descending node of orbit on Tuesday, April 25, 1865, with a magnitude of 1.0584. 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 1.2 days after perigee (on April 24, 1865, at 9:50 UTC), the Moon's apparent diameter was larger.[1]
The path of totality was visible from parts of modern-day Chile, Argentina, Uruguay, Brazil, Angola, Zambia, and extreme northwestern Mozambique. A partial solar eclipse was also visible for much of South America, Antarctica, and Africa.
The total eclipse was also witnessed by the passengers and crew of the SS Great Britain, passing the coastline of Brazil en route from Australia to England;[2] they were able to observe stars in the daytime.
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.[3]
| First Penumbral External Contact | 1865 April 25 at 11:37:22.8 UTC | |
| First Umbral External Contact | 1865 April 25 at 12:36:28.9 UTC | |
| First Central Line | 1865 April 25 at 12:37:48.3 UTC | |
| First Umbral Internal Contact | 1865 April 25 at 12:39:07.9 UTC | |
| Equatorial Conjunction | 1865 April 25 at 13:56:13.5 UTC | |
| Greatest Eclipse | 1865 April 25 at 14:08:34.2 UTC | |
| Greatest Duration | 1865 April 25 at 14:10:32.0 UTC | |
| Ecliptic Conjunction | 1865 April 25 at 14:13:31.6 UTC | |
| Last Umbral Internal Contact | 1865 April 25 at 15:38:11.0 UTC | |
| Last Central Line | 1865 April 25 at 15:39:29.2 UTC | |
| Last Umbral External Contact | 1865 April 25 at 15:40:47.2 UTC | |
| Last Penumbral External Contact | 1865 April 25 at 16:39:54.1 UTC |
| Eclipse Magnitude | 1.05844 | |
| Eclipse Obscuration | 1.12029 | |
| Gamma | −0.48262 | |
| Sun Right Ascension | 02h12m14.0s | |
| Sun Declination | +13°18'55.3" | |
| Sun Semi-Diameter | 15'53.1" | |
| Sun Equatorial Horizontal Parallax | 08.7" | |
| Moon Right Ascension | 02h12m42.7s | |
| Moon Declination | +12°50'29.9" | |
| Moon Semi-Diameter | 16'34.0" | |
| Moon Equatorial Horizontal Parallax | 1°00'47.9" | |
| ΔT | 5.6 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 June 27, 1862 and December 21, 1862 occur in the previous lunar year eclipse set, and the partial solar eclipse on March 16, 1866 occurs in the next lunar year eclipse set.
| Solar eclipse series sets from 1862 to 1866 | |||||||
|---|---|---|---|---|---|---|---|
| Ascending node | Descending node | ||||||
| Saros | Map | Gamma | Saros | Map | Gamma | ||
| 111 | November 21, 1862 Partial | −1.5052 | 116 | May 17, 1863 Partial | 1.0627 | ||
| 121 | November 11, 1863 Annular | −0.8760 | 126 | May 6, 1864 Hybrid | 0.2622 | ||
| 131 | October 30, 1864 Annular | −0.1816 | 136 | April 25, 1865 Total | −0.4826 | ||
| 141 | October 19, 1865 Annular | 0.5366 | 146 | April 15, 1866 Partial | −1.1846 | ||
| 151 | October 8, 1866 Partial | 1.2296 | |||||
All eclipses in this table occur at the Moon's ascending node.
