# Tag Info

Your user need to supply you with information about mean anomaly at fixed time (epoch) $M(t_0)$, and then mean anomaly at the moment $t_1$. Or about known mean motion $n$ instead of current mean anomaly $M(t_1)$. You can also get the mean motion as square root of gravitational parameter $\mu$ divided by cube of semi-major axis, and also as $2\pi$ divided by ...