\begin{table}%t2
    %\centering

    \caption{\label{tab:fluxes}Calibrator fluxes in Jy.}
    \begin{tabular}{lrrrrrr}
      \hline\hline
      & \multicolumn{2}{c}{B0420$-$014} & \multicolumn{2}{c}{B0607$-$157} & \multicolumn{2}{c}{B0528$+$134}\\
                 & 3\mm & 1\mm & 3\mm & 1\mm & 3\mm & 1\mm \\
      \hline
      27.11.1999 &      &      &      &      &  3.5 &  1.4 \\
      30.03.2002 &  4.8 &      &  2.3 &      &      &      \\
      16.04.2002 &  4.8 &      &  2.5 &      &      &      \\
      22.04.2002 &  4.8 &      &  2.4 &      &      &      \\
      23.12.2002 & 12.5 &      &  2.6 &      &      &      \\
      18.03.2003 & 12.0 &  7.8 &  2.1 & 0.87 &      &      \\
      26.03.2003 & 12.8 &      &  2.1 &      &      &      \\
      \hline
    \end{tabular}
      \end{table}