Crommelin and Davidson took the photo that
The 1919 eclipse photograph that confirmed Einstein's theory of relativity was taken by Andrew Crommelin and Charles Davidson in Brazil, not by Arthur
The photograph that proved Albert Einstein's theory of relativity was taken on May 29, 1919, by Andrew Crommelin and Charles Davidson. Their image from Sobral, Brazil, provided the definitive data, yet history primarily remembers the expedition's organizer, Sir Arthur Eddington. This story, reported by Digital Camera World, highlights a familiar frustration for photographers: the person who presses the shutter is often not the one who gets the credit.
The decisive image from Brazil
Eddington led an expedition to Príncipe, off Africa's west coast, to photograph the same total solar eclipse. Bad weather plagued his efforts. He managed to change 16 photographic plates through drifting cloud, blind to what he was capturing. Only two plates were usable, yielding a measurement of starlight deflection around the Sun of about 1.61 arcseconds, with a large margin of error.
Crommelin and Davidson's parallel expedition to Sobral, Brazil, was intended as insurance against such problems. Their main telescope failed when heat warped its mirror, blurring every star image. The crucial data came from their backup instrument, a smaller 4-inch telescope. It produced the sharpest plates of the entire project, measuring a deflection of 1.98 arcseconds with an error margin roughly a quarter the size of Eddington's result.
| Expedition Leader | Location | Instrument Outcome | Measured Deflection (arcseconds) | Error Margin |
|---|---|---|---|---|
| Arthur Eddington | Príncipe, Africa | 2 usable plates from main scope | ~1.61 | Large |
| Andrew Crommelin & Charles Davidson | Sobral, Brazil | Sharp plates from 4-inch backup scope | 1.98 | Roughly 1/4 of Eddington's |
Why Eddington got the credit
Technically, calling the project 'The Eddington experiment' is not wrong. Eddington and astronomer Frank Dyson designed the test and organized both expeditions. Eddington was the public face. He presented the results at the Royal Society in November 1919 and wrote the popular accounts that captured the public imagination. His personal story was also compelling: a Quaker and conscientious objector who had taught himself Einstein's theory during the First World War.
Crommelin and Davidson were staff of the Royal Greenwich Observatory simply doing their jobs. They do not appear as characters in the 2008 BBC drama Einstein and Eddington, which simplifies the story around the two famous men. The pattern is familiar in collaborative shoots: credit often goes to the person attached to the idea and presentation, not necessarily the one who took the final, usable shot. For more on the technical setups behind historic images, see our guide on fixtures.
Eddington deserves immense credit for his vision and courage in conducting the experiment. But the definitive photographic evidence came from a spare telescope in Brazil, operated by two men whose names have been largely forgotten. Understanding the full team behind iconic images is crucial; explore the stats behind other landmark photographic achievements. Andrew Crommelin and Charles Davidson took the photograph that settled one of the greatest scientific debates of the 20th century.
