\begin{table}%t1
\caption{Instrumentation of the used observatories.}\label{tab_instruments}
%\centering
\small
\begin{tabular}{lccr}
\hline\hline
Observatory & Resolution &$\lambda$
\hspace{.1cm}range & \# ${\rm spectra}$ \\
 & (\AA{}) & (\AA{}) & used\\
 \hline 
 \multicolumn{4}{l}{MSST: first half (19/05/2002--27/05/2002):}\\
Steward 2.3 m & 1.8 & 3686--4534 & 2595 \\ 
Siding Spring 2.3 m & 2.2 & 3647--5047 & 852 \\ 
Danish/ESO 1.54 m &5.9 & 3648--5147 & 663\\
\hline 
\multicolumn{4}{l}{Second half (18/06/2002--25/06/2002):}\\
Danish/ESO 1.54 m &5.9 & 3648--5147 & 1562\\
NOT 2.56 m & 9.3 & 3039--6669 & 3320 \\ 
\hline 
\end{tabular}
\end{table}