\begin{table}%t4
 %\centering
\par
 \caption{Apparent and absolute magnitudes of Altair, using the Hipparcos parallax
($\pi = 194.45 \pm 0.94$~mas).}\label{ta:phot_mag}
\begin{tabular}{lccccccccc}
\hline\hline
 & $U$ & $B$  & $ V$  &  $R$  &  $I$  &  $J$  &  $H$  &  $K$ & $L$ \\
\hline
$m_\lambda$    & 1.07 &    0.99  &  0.77  &  0.62  & 0.48  &   0.327  &  0.228  &  0.205 & 0.20 \\
$\sigma(m_\lambda)$  & 0.05 &    0.01  &  0.01  &  0.05  &  0.05  & 0.009  &   0.008  &  0.005 & 0.01 \\
$M_\lambda$    & 2.51 &  2.43  &  2.21  &  2.06  &  1.92 &   1.77  &  1.67  &  1.65 & 1.64 \\
\hline
\end{tabular}
\end{table}