def make_cos_vects(lon_vect, lat_vect):
    """ Convert from longitude (RA or GLON) and latitude (DEC or GLAT) values to directional cosines

    Parameters
    ----------
    lon_vect,lat_vect : np.ndarray(nsrc)  
       Input values

    returns (np.ndarray(3,nsrc)) with the directional cosine (i.e., x,y,z component) values
    """
    lon_rad = np.radians(lon_vect)
    lat_rad = np.radians(lat_vect)
    cvals = np.cos(lat_rad)
    xvals = cvals * np.sin(lon_rad)
    yvals = cvals * np.cos(lon_rad)
    zvals = np.sin(lat_rad)
    cvects = np.vstack([xvals, yvals, zvals])
    return cvects