A total solar eclipse occurred at the Moon's descending node of orbit on Thursday, May 29, 1919,[1] with a magnitude of 1.0719.

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.

[2] This specific total solar eclipse was significant because it helped prove Einstein's theory of relativity.

[3] The eclipse was the subject of the Eddington experiment: two groups of British astronomers went to Brazil and the west coast of Africa to take pictures of the stars in the sky once the Moon covered the Sun and darkness was revealed.

Totality occurred through a narrow path across southeastern Peru, northern Chile, central Bolivia and Brazil after sunrise, across the Atlantic Ocean and into south central Africa, covering southern Liberia, southern French West Africa (the part now belonging to Ivory Coast), the southwestern tip of the British Gold Coast (now Ghana), Príncipe Island in Portuguese São Tomé and Príncipe, southern Spanish Guinea (now Equatorial Guinea), French Equatorial Africa (the parts now belonging to Gabon and R. Congo, including Libreville), Belgian Congo (now DR Congo), northeastern Northern Rhodesia (now Zambia), the northern tip of Nyasaland (now Malawi), German East Africa (now belonging to Tanzania) and northeastern Portuguese Mozambique (now Mozambique), ending near sunset in eastern Africa.

Mars had its conjunction with the Sun twenty days earlier and shone at 2nd magnitude a few degrees to the west.

Deneb, Altair, Fomalhaut and Achernar were the only 1st-magnitude stars well clear of the horizon; Vega, Aldebaran, Rigel and Canopus were very low.

[7][8] Einstein's idea meant that extremely small matter particles could produce massive amounts of energy.

One expedition was led by Sir Arthur Eddington to the island of Príncipe (off the west coast of Africa), the other by Andrew Claude de la Cherois Crommelin and Charles Rundle Davidson to Sobral in Brazil.

[16] From the findings from these expeditions Dyson is quoted saying, "After a careful study of the plates, I am prepared to say that they confirm Einstein's prediction.

"[19] He continued to explain that it left little doubt about light deflection in the area around the Sun and it was the amount Einstein demanded in his generalized theory of relativity.

[22] However, a lack of funding, preparation, and time of total coverage of the sun would have also caused issues for the astronomers.

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