\begin{table}%t1
%\centering
\par
\caption{\label{tab1}Data used to search for transient objects.}
\begin{tabular}{lccc}
\hline
\hline
\noalign{\smallskip}
 Date      & Exposure & Seeing & 90\% detection  \\
          & [min] & [arcsec] & efficiency [mag]    \\
\hline
\noalign{\smallskip}
%\noalign{\smallskip}
\multicolumn{4}{c}{Abell 1689 -- VLT/ISAAC $SZ$-band}\\
\hline
%\noalign{\smallskip}
\multicolumn{4}{c}{pointing 1}\\
2003 02 09$^a$  &   159 &   0.52     & 24.28, transient \\
2003 04 27      &    43 &   0.43     & 24.28, transient  \\
2004 01 13      &    43 &   0.52     & 23.58, non-detect   \\
2004 02 14      &    43 &   0.58     & 23.64, non-detect \\
\hline
\multicolumn{4}{c}{pointing 2}\\
2003 01 16      &    43 &   0.58     & 23.48\\
2003 02 15      &    43 &   0.50     & 23.60 \\
2003 04 27      &    86 &   0.44     & 23.64  \\
2004 01 12      &    43 &   0.55     & 23.64\\
\hline
\multicolumn{4}{c}{pointing to cluster core}\\
2007 04 08      &   117 &   0.64 &  23.95  \\
2007 05 14/15   &   117 &   0.65 &  23.95  \\
2007 06 06      &    39 &   0.70 &  23.15  \\
\hline
\multicolumn{4}{c}{AC 114 -- VLT/ISAAC $J$-band}\\
\hline
%\noalign{\smallskip}
2002 08 20 &      108   &   0.49 & 23.87 \\
2007 07 13$^b$ &  234   &   0.43 & 24.04 \\
2007 08 09 &      117   &   0.73 & 23.79 \\
2007 09 02 &      117   &   0.55 & 23.83 \\
2007 09 28 &      117   &   0.46 & 24.04 \\
\hline
%\noalign{\smallskip}
\multicolumn{4}{c}{Abell 1835 -- VLT/ISAAC $SZ$-band}\\
\hline
%\noalign{\smallskip}
area 1          &       &        &         \\
2004 04 20      & 231 	&   0.49 & 24.06   \\ 
2004 05 15	& 135 	&   0.62 & 24.06   \\
2007 04 18	& 117 	&   0.79 & 23.80   \\ 
2007 05 18	& 78  	&   0.74 & 23.83   \\
2007 07 18	& 117 	&   0.62 & 23.80   \\
area 2    	&     	& 	 &	   \\
2007 04 18      & 117 	&   0.79 & 23.70   \\
2007 05 14/18   & 60  	&   0.80 & 23.45   \\
2007 07 18      & 117 	&   0.62 & 23.70   \\
\hline
\end{tabular} \\
$^a$ Average of observations obtained on 5, 11 and 15 February.\\
$^b$ Average of observations obtained on 11, 12, 13 and 15 July.
\end{table}