\begin{table}%T2
\caption{Observations Log.}
\label{m51log}
%\centering
\par
\begin{tabular}{rccccccccc}
\hline\hline
\noalign{\smallskip}
Transition & Date    	& Freq	& $T_{\rm sys}$ & Beam 	& $\eta _{\rm mb}$ & $t$(int) & \multicolumn{3}{c}{Map parameters} \\
& & & & Size & & & Points & Size & Spacing \\
	   & (MM/YY) 	& (GHz)	& (K)	  & ($\arcsec$) & 	       	   & (s) & & ($\arcsec$) & ($\arcsec$) \\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
$\co$ $J=2{-}1$	  & 12/90; 05/91 & 230 &  920 & 21 & 0.69 &  480 &  40 & $30\times50$ & 10 \\
$\co$ $J=3{-}2$    & 12/93        & 345 & 1475 & 14 & 0.53 &  400 &  18 & $40\times50$ & 12 \\
	   	  & 05/97; 05/01 &     &  660 &    & 0.60 &   70 & 400 & $60\times120$ & 6 \\
$\co$ $J=4{-}3$    & 03/94; 04/96 & 461 & 3950 & 11 & 0.50 &  600 &  16 & $24\times20$ &  6 \\
		  & 12/01        &     & 2100 &	   & 0.52 & 1200 &   6 & $18\times12$ &  6 \\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
$\treizeco$ $J=2{-}1$ & 06-95         & 220 &  370 & 21 & 0.69 & 2520 &  1 & --  & --  \\
$\treizeco$ $J=3{-}2$ & 05-97; 05/01  & 330 &  600 & 14 & 0.63 & 3600 &  9 & $15\times15$ & 7.5 \\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
CI $^{3}$P$_{1}$--$^{3}$P$_{0}$ & 11-94 & 492 & 6675 & 10 & 0.53 &  960 & 4 & -- & -- \\
\hline
\end{tabular}
\end{table}