\begin{table}%t1
%\centering
\par
\caption{Atomic data of Na lines. $\log gf$ values and damping constants have
been determined from solar spectrum fits.\label{table1}}
%\centering
$$
{\begin{tabular}{rr@{${-}$}lrr}
\hline\hline\noalign{\smallskip}
$\lambda$~ [\AA] & \multicolumn{2}{c}{Transition} & $\log gf$ & $\log C_6$\\
\hline\noalign{\smallskip}
 5682.642 &  $\rm 3p~^2{\rm P}^{0}_{1/2}$ & $\rm 4d~^2{\rm D}_{3/2}$ & --0.72  & --30.05  \\
 5688.214 &  $\rm 3p~^2{\rm P}^{0}_{3/2}$ & $\rm 4d~^2{\rm D}_{5/2}$ & --0.47  & --30.05  \\
 5889.959 &  $\rm 3s~^2{\rm S}_{1/2}$ & $\rm 3p~^2{\rm P}^{0}_{1/2}$ & +0.11  & --31.60  \\
 5895.932 &  $\rm 3s~^2{\rm S}_{1/2}$ & $\rm 3p~^2{\rm P}^{0}_{3/2}$ & --0.19  & --31.60  \\
 6154.228 &  $\rm 3p~^2{\rm P}^{0}_{1/2}$ & $\rm 5s~^2{\rm S}_{1/2}$ & --1.57  & --29.78  \\
 6160.751 &  $\rm 3p~^2{\rm P}^{0}_{3/2}$ & $\rm 5s~^2{\rm S}_{1/2}$ & --1.28  & --29.78  \\
 8183.260 &  $\rm 3p~^2{\rm P}^{0}_{1/2}$ & $\rm 3d~^2{\rm D}_{3/2}$ &  0.28  & --30.73  \\
 8194.800 &  $\rm 3p~^2{\rm P}^{0}_{3/2}$ & $\rm 3d~^2{\rm D}_{5/2}$ &  0.49  & --30.73  \\
\noalign{\smallskip}
\hline
\end{tabular}}
$$
\end{table}