The May 29, 1919 total solar eclipse.

Solar_eclipse_1919_positive-eddington-700x899

One of the original plates from the 1919 solar eclipse used to measure the effects of general relativity. Note the horizontal lines that mark stars that were used for the measurements.

 

Credit: F. W. Dyson, A. S. Eddington, and C. Davidson "A Determination of the Deflection of Light by the Sun's Gravitational Field, from Observations Made at the Total Eclipse of May 29, 1919"

http://commons.wikimedia.org/wiki/File:1919_eclipse_positive.jpg

 

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