def ratioTerminatorToStar(H_p, R_p, R_s):
    """Calculates the ratio of the terminator to the star assuming 5 scale
    heights large. If you dont know all of the input try
    :py:func:`calcRatioTerminatorToStar`

    .. math::
        \\Delta F = \\frac{10 H R_p + 25 H^2}{R_\\star^2}

    Where :math:`\\Delta F` is the ration of the terminator to the star,
    H scale height planet atmosphere, :math:`R_p` radius of the planet,
    :math:`R_s` radius of the star

    :param H_p:
    :param R_p:
    :param R_s:
    :return: ratio of the terminator to the star
    """
    deltaF = (10 * H_p * R_p + 25 * H_p ** 2) / R_s ** 2
    return deltaF.simplified
