Gravitational red shift and time delay of radar echo in f(R)-gravity

Sobouti proposes an action-based f(R) modification of Einstein's gravity, which admits a similar Schwarzschild metric. A test star moving in such a space-time acquires a constant asymptotic speed at large distances. As we are concerned with two classical tests of Einstein's theory which are gravitational red shift of spectral lines and time delay of radar echo passing the sun, we shall calculate them in the f(R)-gravity and show that the results are consistent with the experimental observation data.