The proper time integral (see Weinberg S, 1972. Gravitation and Cosmology, pp. 180-187), which I calculated was: Int(dta) = +-Int(dr/(1/E-1+2MG/r-J^2/(E*r^2)+2MG*J^2/(E*r^3))^(1/2)) and substitution u=1/r. So I got ta=ta(P), u=u(P), 0=P=Pi. Next The coordinate time solution which corresponds to this analytic solution: Int(dt) =+-Int((dta/dP) dP/(sqrt(E)*(1-2MG*u(P))). Best Regards, Hannu Poropudas, Finland.