\begin{table}%t3
  \caption{\label{tab:table3}Mean results from the local astrometric corrections$^{a}$.}
\small%\centerline
 {
        \begin{tabular}{lrrrrrrr}
      \hline \hline
&&&&&&& \\[-8pt]
      Solution & $Nq$ & $\overline{Ns}$ &
      $\overline{C\alpha \cos \delta}$ & $\overline{C\delta}$ &
      $Nrad$ & $\overline{\Delta\alpha \cos \delta}$ & $\overline{\Delta\delta}$ 
       \\
     \hline 
BU6 & 47~822 & 13.0 & --23.5 (106.2) & --145.3 (104.2) &
 1320 &   --43.5 (177.0)  & +12.2 (171.6) \\
BN6 & ~3023 & ~14.1 & +4.2 (45.6) & --230.0 (81.7) &
 123 &   --70.5 (136.6)  & --9.9 (121.6) \\
BT6 & 83~951 & ~52.8 & +3.3 (107.9) & --178.8 (111.2) &
 1897 &   --18.2 (172.9)  & --12.0 (167.5) \\
BU4 & 43~991 & ~13.8 & --21.8 (105.1) & --147.8 (103.6) &
 1273 &   --41.9 (176.6)  & +11.0 (171.8) \\
BN4 & ~3095 & ~14.1 & +4.7 (45.8) & --229.1 (80.3) &
 ~124 &   --68.8 (136.6)  & --11.4 (121.9) \\
BT4 & 84~012 & ~52.7 & +3.2 (107.7) & --178.9 (111.1) &
 1896 &   --18.6 (172.2)  & --12.9 (167.0) \\
GU6 & 76~671 & ~22.7 & --58.4 (109.7) & --8.8 (91.4) &
 1633 &   --27.2 (178.3)  & +33.7 (166.2) \\
GN6 & ~4131 & ~16.3 & --56.3 (51.8) & --5.4 (87.8) &
 ~150 &   +21.8 (148.8)  & --11.9 (136.5) \\
GT6 & 93~976 & 119.1 & --55.9 (135.4) & --27.3 (119.2) &
 1984 &   --5.1 (162.3)  & +0.4 (157.3) \\
GU4 & 77~110 & ~22.6 & --58.2 (109.9) & --8.9 (91.4) &
 1634 &   --26.5 (178.2)  & +33.0 (165.5) \\
GN4 & ~4356 & ~16.2 & --56.6 (51.5) & +6.2 (86.3) &
 ~154 &   +20.1 (150.0)  & --14.0 (133.3) \\
GT4 & 93~978 & 119.1 & --55.8 (135.4) & --27.4 (119.3) &
 1983 &   --5.2 (161.8)  & +0.3 (157.4) \\
SU6 & 59~184 & ~30.0 & +6.5 (22.3) & +14.2 (26.2) &
 ~241 &   +5.7 (44.3)  & +25.6 (49.9) \\
SN6 & ~4035 & ~16.0 & --7.6 (24.2) & --26.8 (48.9) &
 ~~37 &   --15.0 (45.7)  & --1.8 (37.7) \\
ST6 & 74~838 & 167.6 & +5.3 (49.4) & +20.8 (55.5) &
 ~301 &   +9.8 (65.9)  & +30.1 (63.1) \\
SU4 & 59~125 & ~30.0 & +6.4 (21.8) & +14.1 (25.8) &
 ~240 &   +6.2 (43.3)  & +24.1 (47.6) \\
SN4 & ~4036 & ~16.0 & --7.5 (23.9) & --26.5 (48.3) &
 ~~37 &   --14.7 (45.4)  & --0.8 (37.0) \\
ST4 & 74~838 & 167.6 & +5.4 (49.3) & +19.9 (55.2) &
 ~301 &   +9.7 (65.9)  & +29.0 (63.3) \\
 \hline 
\end{tabular}}
\medskip
$^{a}$ Comparative results given by all types of local correction designed. The solutions nomenclature is formed by one letter designating the quasar position input catalog, followed
by one letter designating the stellar reference frame, and by the codes~$6$ and~$4$ informing whether the algorithm is of the six or four-parameter model.  $Nq$~is the number of quasars for which a given local correction was possible and succeeded. $\overline{Ns}$~is the average number of catalog stars contributing to the solution.   $\overline{C\alpha ~{\rm cos}~ \delta}$ and $\overline{C\delta}$~columns bring the mean corrections on right ascension and declination, and the
standard deviations (in brackets). The final two columns show the average optical to radio offset, preceded by the number of sources entering the average~($Nrad$). All angular values are in milli-arcsec. See the text for detailed explanations on the solutions and samples.
\end{table}