There is a famous image that one often sees taken by Eddington during the 1919 solar eclipse illustrating gravitational light bending as predicted by Einstein.
Can someone explain what exactly is shown in the image? What is the dark black stuff around the Sun? Is the dark black arc in the bottom left meant to be the bending of light?
It's a photographic negative. The white disk is the face of the moon, which covers the sun and is dark. The dark halo is the sun's corona, which is light. The arc is just a smudge or damage.
You can't take a photo of a ray of light. To show up on the film, the ray has to enter the camera and strike the film.
The bending of the light is shown by the displacement of the stars from their expected positions. The stars are marked with horizontal lines.
