def estimate_global_scale(detector_range, n, m0):
    """
    :param detector_range: max wavelength minus min wavelength of the detector in angstroms, e.g. 5000
    :param n: the number of distinct diffraction orders on the detector, e.g. 67
    :param m0: the principle order number, e.g. 52
    :return: The global scale constant for the wavelength solution, in units of Angstrom.
    """
    return detector_range * (1/m0 - 1/(m0 + n))**(-1)