\begin{table}%t1
\caption{\label{tab:obs}Details of the three Hinode/SP data sets used.}  
\small %\centering
\par
\begin{tabular}{l c c c c c c c c c c}
\hline \hline\noalign{\smallskip}
 & Date & Time & FOCUS & $\mu$ & Size & Exposure & Noise & $\langle B^{\rm T}_{\rm app}\rangle$ & $\langle |B^{\rm L}_{\rm app}|\rangle$ & $\langle B^{\rm L}_{\rm app}\rangle$  \\
 & [dd/mm/yy]& UT& & & [arcsec] & time [s] & $10^{-3} I_{\rm c}$ & Mx/cm$^2$ & Mx/cm$^2$ & Mx/cm$^2$\\
\hline
set I & $10/09/07$ & 08:00:00 & 2031 & 1 & $58 \times 164$ & 9.6 & 0.8 & 56.7 & 9.7 & 1.6 \\
set II & $27/02/07$ & 00:20:09 & 2048 & 1 & $0.16 \times 164$ & 67.2 & 0.25 & 54.6 & 11.0 & 1.7 \\
set III & $09/09/07$ & 13:05:05 & 2029 & 0.4 & $160 \times 32$ & 9.6 & 1 & 53.5 & 6.8 & 0.3 \\
\hline
\end{tabular}
\tablefoot{The last
three columns, from left to right, give the mean values of the
transversal (with respect to the line of sight), unsigned
longitudinal, and signed longitudinal magnetic flux density.}
\vspace*{4mm}
\end{table}