"James Bradley"
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James Bradley
Public DomainJames Bradley
  James Bradley (1693-1762) was Astronomer Royal from 1742.   His discoveries include the aberration of light and the nutation (slight irregular “nodding” due to tidal forces) of the Earth’s axis.   Stellar aberration refers to an effect whereby the apparent motion of a stellar body seems to vary dependent on the movement of the observer.   Bradley’s observations of the apparently variable motion of the star γ Draconis formed proof of the Earth’s own movement.