% OT9

constants
e = 0.5;
T = 12*3600;
%----

a = k3_SMA(T)

l = a*(1-e^2)

v_eq = visviva(l, a)

E = 2*atan(sqrt(1/3))

t_eq = (E-e*sin(E))/(2*pi)*T/3600

duration(t_eq,0,0)