\begin{table}%t2
%\centering
\par
\caption {Technical characteristics of the telescopes used for the
  $J$-band follow up.\label{teltab}} 
\begin{tabularx}{18cm}{XXXXXX} \hline\hline
 Telescope Name& Diameter(m) & Instrument  & Exp time for 5$\sigma$
 detection of $J({\rm AB})=21$ object  & Pixel scale & Field of view \\ \hline  
NTT & 3.6  & SOFI & 45~s & 0.288'' & $4.9' \times 4.9'$ \\\hline
Kitt Peak 2.1~m & 2.1 &  SQIID & $\sim$320~s  & 0.69'' & $5.1' \times 5.3'$   \\\hline
 Harlan-Smith Telescope &  2.7  & ROKCAM  & $\sim$3000s &0.35\arcsec &  
 $1.5' \times 1.5'$\\\hline
 NOT & 2.5 &  NOTCam &$\sim$100~s   & 0.24\arcsec & $4.0' \times 4.0'$\\\hline
\end{tabularx}
\end{table}