def _m_to_e(cls, e, M):
        """Conversion from Mean Anomaly to Eccentric anomaly

        Procedures for solving Kepler's Equation, A. W. Odell and  R. H. Gooding,
        Celestial Mechanics 38 (1986) 307-334
        """

        k1 = 3 * np.pi + 2
        k2 = np.pi - 1
        k3 = 6 * np.pi - 1
        A = 3 * k2 ** 2 / k1
        B = k3 ** 2 / (6 * k1)

        m1 = float(M)
        if abs(m1) < 1 / 6:
            E = m1 + e * (6 * m1) ** (1 / 3) - m1
        elif m1 < 0:
            w = np.pi + m1
            E = m1 + e * (A * w / (B - w) - np.pi - m1)
        else:
            w = np.pi - m1
            E = m1 + e * (np.pi - A * w / (B - w) - m1)

        e1 = 1 - e
        risk_disabler = (e1 + E ** 2 / 6) >= 0.1

        for i in range(2):
            fdd = e * sin(E)
            fddd = e * cos(E)

            if risk_disabler:
                f = (E - fdd) - m1
                fd = 1 - fddd
            else:
                f = cls._e_e_sin_e(e, E) - m1
                s = sin(E / 2)
                fd = e1 + 2 * e * s ** 2
            dee = f * fd / (0.5 * f * fdd - fd ** 2)

            w = fd + 0.5 * dee * (fdd + dee * fddd / 3)
            fd += dee * (fdd + 0.5 * dee * fddd)
            E -= (f - dee * (fd - w)) / fd

        E += M - m1

        return E
Conversion from Mean Anomaly to Eccentric anomaly

        Procedures for solving Kepler's Equation, A. W. Odell and  R. H. Gooding,
        Celestial Mechanics 38 (1986) 307-334