relative velocities. Bradley's explanation cannot account for situations such as the water telescope, nor for many other optical effects (such as interference) that might occur within the telescope. This is because in the Earth's frame it predicts that the direction of propagation of the light beam in the telescope is not normal to the wavefronts of the beam, in contradiction with Maxwell's theory of electromagnetism. It also does not preserve the speed of light c between frames. However, Bradley did correctly infer that the effect was due to relative velocities. See also Apparent place Stellar parallax Astronomical nutation Proper motion Timeline of electromagnetism and classical optics Relativistic aberration Notes References Further reading P. Kenneth Seidelmann (Ed.), Explanatory Supplement to the Astronomical Almanac (University Science Books, 1992), 127–135, 700. Stephen Peter Rigaud, Miscellaneous Works and Correspondence of the Rev. James Bradley, D.D. F.R.S. (1832). Charles Hutton, Mathematical and Philosophical Dictionary (1795). H. H. Turner, Astronomical Discovery (1904). Thomas Simpson, Essays on Several Curious and Useful Subjects in Speculative and Mix'd Mathematicks (1740). :de:August Ludwig Busch, Reduction of the Observations Made by Bradley at Kew and Wansted to Determine the Quantities of Aberration and Nutation (1838). External links Courtney Seligman on Bradley's observations Electromagnetic radiation Astrometry Radiation