\begin{table}%t1
\caption{\label{table1}Differential rotation parameters $A$ and $B$ from Eq.~(1) and their standard errors~$M$ in deg~day$^{-1}$ for the interactive method.}
%\centering
\par
\begin{tabular}{rrrrrr}
\hline \hline \noalign{\smallskip}
Year  &  Month  & $N$      &   $A \pm M_A$      & $B \pm M_B$       & Source \\
\hline
1998  &   6     &   89     &   $14.62 \pm 0.09$ & $-3.05 \pm 0.40$  &  1    \\
1998  &  11     &   48     &   $14.60 \pm 0.13$ & $-3.61 \pm 0.47$  &  1    \\
1998  &  12     &  175     &   $14.46 \pm 0.08$ & $-3.13 \pm 0.22$  &  1    \\
1999  &   3     &  161     &   $14.70 \pm 0.09$ & $-3.47 \pm 0.29$  &  1    \\
1999  &   4     &  199     &   $14.55 \pm 0.07$ & $-2.78 \pm 0.36$  &  1    \\
1999  &   5     &  250     &   $14.68 \pm 0.07$ & $-3.68 \pm 0.24$  &  1    \\
1999  &  10     &  149     &   $14.67 \pm 0.08$ & $-3.08 \pm 0.24$  &  2    \\
1999  &  11     &  184     &   $14.66 \pm 0.09$ & $-3.56 \pm 0.23$  &  2    \\
\hline
\end{tabular}
\tablefoot {1. Braj\v sa et~al. (\cite{Braj01a}). 2. Braj\v sa et~al. (\cite{Braj08a}). $N$~-- the number  of traced structures in each month after applying the two-step velocity filter.}
\end{table}