\begin{table}%t4		
     \caption{\label{ObservingCon}Observing conditions.}			
     %\centerline
{\begin{tabular}{c c c c c c c c}
     \hline\hline\noalign{\smallskip}
      Comet & Observation time (UT)$^a$ & {\it r} (AU)$^b$ & $\Delta$ 
      (AU)$^c$ & $\alpha$ ($^{\circ}$)$^d$ 
      & PA ($^{o}$) $^e$
      & Total exposure time $^f$
      & Airmass$^g$\\
     \hline
     C/2003 O1 (LINEAR) & 2005 May 16 02:13 & 7.39 & 6.89 & 9.96  & 180.3 & 3000 & 1.094 \\
     C/2004 K1 (Catalina) & 2005 May 15 23:51 & 3.43 & 2.57 & 10.3 & 204.3 & 1500 & 1.139 \\
     \hline
     \end{tabular}}
     \medskip
\par
     $^a$ UT time in the middle of the total exposure 
      time (coadded image). $^b$ Heliocentric distance. $^c$ Geocentric distance. $^d$ Sun-target-observer angle. $^e$~Position angle of the extended Sun-target radius vector. $^f$ Resulting from coadding of the individual frames. $^g$ In the middle of the total exposure time (coadded image).
\end{table}