Effects of the Sun's time-retarded gravitational field on the orbital   motions of Mercury and Halley's Comet
  The neoclassical causal version for Newton's acausal gravitational theory explains exactly the anomalous speed-changes observed for six Earth flybys and an anomalous lunar orbital speed-change (arXiv:1105.3857v10). This article estimates the effects of the neoclassical causal theory on the orbital motions of two objects revolving around the Sun, Mercury and Halley's Comet. The change in the period for Mercury is predicted to be about +1.86 ms per year, and the predicted change in the angle for perihelion is -0.032 arc seconds per century, for which the magnitude is negligible compared with the relativistic advance of +43 arc seconds per century. The period for Halley's Comet, 75.3 years, is predicted to decrease by about 10 minutes. Therefore, the neoclassical causal theory does not conflict with general relativity theory, and it is not the cause for a delay of one or two weeks in the return time of Halley's Comet. 
J. C. Hafele
physics.gen-ph