Royal Greenwich Observatory Archives
Photographs of the sun in total eclipse taken at Sobral in equatorial Brazil, 1919, and the Observation Station
Sobral, Brazil, 1919

Arthur Eddington and Frank Dyson, former colleagues at Greenwich, fully appreciated how important were the papers published by Albert Einstein. Far from it being impossible to detect tiny deflections of light as predicted, the astronomers realised that as it is such a massive body, the sun when close to the stars in the sky would make them appear to shift compared with their positions when it is absent. The only time the sun would not overwhelm starlight to allow observations close by would be during a total solar eclipse. Eddington and Dyson knew there would be a favourable eclipse in May 1919. With a clear sky the Greenwich observers at Sobral had five minutes of totality to expose the vital stellar photographs. The associated landscape photograph shows the Sobral Station, the temporary buildings giving cover in the heat and protecting the photoheliograph. Measurement of these plates later bore out Einstein’s predictions.

MS RGO 8/123.2, f. 25 and photographs 56 and 64–67