\begin{table}%t1
\par
\caption {\label{tab1}Parameters of NGC~6522 given in the literature.   }
%\centerline
 {\begin{tabular}{llllll@{}llll}
\hline
\hline
$E(B-V)$ &
[Fe/H] &
$v_{\rm r}$ &
$(m-M)$ &
 $d_{\odot}$ &
Ref.  \\
 &
 &
(km~s$^{-1}$) &
 &
 (kpc) & \\
\noalign{\vskip 0.2cm}
\noalign{\hrule\vskip 0.2cm}
\noalign{\vskip 0.2cm}
0.45    & --1.44            &       +8   & 15.37  & 6.2    & 1 \\
--      & --1.44            & --3    & --     & --     & 2  \\
0.48    & --1.44            & --21.1      & 16.52  & 7.8    & 3 \\
0.50    & --1.44            & --18.7      & --     & --      & 4 \\
--     & --1.50/--1.21      & --         & --    & --     & 5  \\
0.52    & --1.60             & --         & --     & --    & 6 \\
0.39    & --1.28            & --28.5      & --    & 7.3   & 7 \\
0.48    & --1.44            & --         & --    & 7.4   & 8 \\
--      &--1.44/--1.42/--1.35 & --         & ---    & --     & 9 \\
0.48    & --1.44            & --         & ---    & 7.8    & 10 \\
\noalign{\smallskip} \hline 
\end{tabular}}
\smallskip
References: 1 Zinn (\cite{Zinn85}); 2 Armandroff (\cite{Armandroff89});
3 Harris (\cite{Harris96}); 4~Rutledge et~al. (\cite{Rutledge97}a);  5 Rutledge et~al. (\cite{Rutledge97}b) (given in Zinn \& West \cite{Zinn84} and Carretta \& Gratton metallicity scales); 6 Terndrup \& Walker (\cite{Terndrup94});
7 Terndrup et~al. (\cite{Terndrup98}) 
($A_{V}=1.42$ is given);
8 Piotto et~al. (\cite{Piotto02}); 9 Kraft \& Ivans (\cite{Kraft03}); 10 Bica et~al. (\cite{Bica06}).
\end{table}