def _aperture_mean_nomask(ap, image, **kwargs):
    """
    Calculate the mean flux of an image for a given photutils
    aperture object. Note that we do not use ``_aperture_area``
    here. Instead, we divide by the full area of the
    aperture, regardless of masked and out-of-range pixels.
    This avoids problems when the aperture is larger than the
    region of interest.
    """
    return ap.do_photometry(image, **kwargs)[0][0] / ap.area()