Notes. All angular values are in mas. The structure indices were selected by considering that the dates of the VLBI experiments should be closest to those of the respective optical observations presented here (see also Tables 2 and 3). Column 1: source identification; Cols. 2 and 3: X- and S-band structure indices, respectively, as obtained from the BVID; Col. 4: object category (defining – Y (yes) or not defining – N (no)) indicating the object’s presence in the ICRF2 defining source list (http://hpiers.obspm.fr/icrs-pc/); Col. 5: goodness of fit (gof) as given by Gontier et al. (2001); Col. 6: V magnitude; Col. 7: object type – BL Lac (B), quasar (Q), and galaxy (G); Col. 8: redshift; Col. 9: near-infrared colour index J − K_s as obtained from the 2MASS; Col. 10: imager name; Cols. 11 and 12 give the differences in the sense observed minus ICRF2 positions, to the sources whose IDs are listed in Col. 1; Cols. 13 and 14 give the values of σ_I, as described in Sect. 4, to the sources whose IDs are listed in Col. 1; Cols. 15 and 16 give the value of 3σ, as described in Sect. 4, to the sources whose IDs are listed in Col. 1. The notation α ∗  indicates multiplication by cosδ. Magnitudes, object type, and redshifts were mostly taken from the “Information on radiosources” link at http address given above. The SIMBAD was queried in case of missing information on the redshifts. The concerned sources are: 0237 − 233, 1127 − 145, 1445 − 161, 2000 − 330, 2344 + 092. Regarding the magnitude, it should be noticed that these objects are variable.