\begin{table}%t2
\caption{\label{tab2}Visible spectroscopy performed at TNG.}             
%\centerline
 {\begin{tabular}{cccccccc}        % centered columns (4 columns)
\hline\hline                 % inserts double horizontal lines
\# & Date & UT     &  Texp  & airm  & Sol & airm  & Spect. \\
   &  &  (start)   &        &       & an  & sol   & slope \\
   &  &  (h:m)     &  (s) &       &     & an    & S(\%10$^3~\AA$) \\
\hline                        % inserts single horizontal line
1 & 17 Apr. &  23:56 &   900  &  1.27   & 1 &    1.16 & $6.88\pm0.65$\\
2 & 18 Apr. &  23:56 &   900  &  1.25   & 2 &    1.14 & $7.09\pm0.65$\\
3 & 19 Apr. &  03:04 &   900  &  1.36   & 2 &    1.14 & $7.12\pm0.65$\\
4 & 20 Apr. &  00:03 &   600  &  1.23   & 1 &    1.19 & $7.48\pm0.65$\\
5 & 20 Apr. &  00:15 &   900  &  1.22   & 1 &    1.19 & $8.26\pm0.65$\\
6 & 20 Ap.r &  00:34 &   900  &  1.20   & 1 &    1.19 & $7.75\pm0.65$\\
7 & 20 Apr. &  01:29 &   900  &  1.19   & 1 &    1.19 & $7.25\pm0.65$\\
8 & 20 Apr. &  01:50 &   900  &  1.21   & 1 &    1.19 & $6.48\pm0.65$\\
\hline
\end{tabular}}
\par
\smallskip
1. La 102-1081; 2. hd 144873.
\end{table}