The first accurate measurement of the speed of light was made by Roemer in the 17th century. His measurements were based on observations of
(a) The timing of the eclipses of the binary stars Alpha and beta Centauri
(B) Refraction of light from a star when the star was eclipsed by the moon
(C) The timing of eclipses of one of Jupiter's moons
(D) The periodic eclipsing of Venus by the sun
1 answer
http://en.wikipedia.org/wiki/R%C3%B8mer%27s_determination_of_the_speed_of_light
2 answers