def _true_anom_to_phase(true_anom, period, ecc, per0):
    """
    TODO: add documentation
    """
    phshift = 0

    mean_anom = true_anom - (ecc*sin(true_anom))*u.deg

    Phi = (mean_anom + per0) / (360*u.deg) - 1./4

    # phase = Phi - (phshift - 0.25 + per0/(360*u.deg)) * period
    phase = (Phi*u.d - (phshift - 0.25 + per0/(360*u.deg)) * period)*(u.cycle/u.d)

    return phase
def _true_anom_to_phase ( true_anom , period , ecc , per0 ) : phshift = 0 mean_anom = true_anom - ( ecc * sin ( true_anom ) ) * u . deg Phi = ( mean_anom + per0 ) / ( 360 * u . deg ) - 1. / 4 phase = ( Phi * u . d - ( phshift - 0.25 + per0 / ( 360 * u . deg ) ) * period ) * ( u . cycle / u . d ) return phase
TODO: add documentation