def classify_sources(catalog, sources=None):
    """ Convert moments_central attribute for source catalog into star/cr flag.

    This algorithm interprets the central_moments from the source_properties
    generated for the sources as more-likely a star or a cosmic-ray.  It is not
    intended or expected to be precise, merely a means of making a first cut at
    removing likely cosmic-rays or other artifacts.

    Parameters
    ----------
    catalog : `~photutils.SourceCatalog`
        The photutils catalog for the image/chip.

    sources : tuple
        Range of objects from catalog to process as a tuple of (min, max).
        If None (default) all sources are processed.

    Returns
    -------
    srctype : ndarray
        An ndarray where a value of 1 indicates a likely valid, non-cosmic-ray
        source, and a value of 0 indicates a likely cosmic-ray.
    """
    moments = catalog.moments_central
    if sources is None:
        sources = (0, len(moments))
    num_sources = sources[1] - sources[0]
    srctype = np.zeros((num_sources,), np.int32)
    for src in range(sources[0], sources[1]):
        # Protect against spurious detections
        src_x = catalog[src].xcentroid
        src_y = catalog[src].ycentroid
        if np.isnan(src_x) or np.isnan(src_y):
            continue
        x, y = np.where(moments[src] == moments[src].max())
        if (x[0] > 1) and (y[0] > 1):
            srctype[src] = 1

    return srctype