Solar eclipse of August 18, 1868

Solar eclipse of August 18, 1868
Map
Type of eclipse
Nature	Total
Gamma	−0.0443
Magnitude	1.0756
Maximum eclipse
Duration	407 s (6 min 47 s)
Coordinates	10°36′N 102°12′E / 10.6°N 102.2°E / 10.6; 102.2
Max. width of band	245 km (152 mi)
Times (UTC)
Greatest eclipse	5:12:10
References
Saros	133 (37 of 72)
Catalog # (SE5000)	9207

A total solar eclipse occurred on August 18, 1868, also known as "The King of Siam's eclipse". 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.

The eclipse was predicted more precisely by King Mongkut of Thailand than it was by French astronomers. The eclipse allowed for the discovery of helium by both Pierre Janssen and Norman Lockyer, who observed Solar prominences with spectroscopes.