The columns list:

(1) J2000 Right Ascension [hr min sec].

(2) J2000 Declination [deg min sec].

(3) The largest FWHM beam for which the calibrator is suitable [arcsec].

(4) The 1.4 GHz flux density from the NVSS [Jy].

(5) The 4.85 GHz flux density from the S5, GB6, or Parkes-MIT-NRAO surveys [Jy].