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 6.5 days after perigee (on August 17, 1868, at 22:35 UTC), the Moon's apparent diameter was larger.

[1] The path of totality was visible from parts of modern-day Ethiopia, Eritrea, Djibouti, Yemen, India, the Andaman and Nicobar Islands, Myanmar, Thailand, Cambodia, Vietnam, Malaysia, Brunei, Indonesia, and Papua New Guinea.

The eclipse allowed for the discovery of helium by both Pierre Janssen and Norman Lockyer, who observed Solar prominences with spectroscopes.

French astronomer Pierre Janssen observed the eclipse from Guntur in Madras State, British India.

[6][7] King Mongkut, also known as Rama IV of Siam, was able to calculate and predict the solar eclipse two years earlier.

The eclipse took place precisely as the king had predicted, the total phase lasting six minutes and 46 seconds.

Their appearance and longitude are irregular due to a lack of synchronization with the anomalistic month (period of perigee).