Light Speed Measurements from Roemer and Bradley to the GPS System
Ralph Sansbury
A survey of light speed measurements suggests that light speed can be calibrated to be equal to the standard speed of light assumption for distances up to 12000 miles about, but that for greater distances, such as that between the Earth and spacecraft, the results are not so clear. Also that our knowledge of the speed of light delay from stars is confounded with the speed of light delay between lenses and with the effects of light intensity at the lens or ccd array etc. Thus, the actual speed of light delay from astronomical distances is not as obvious as commonly believed.
