\begin{table}%t1
\caption{\label{obslog}Log of the observations of V372~Ser.}
\small%\centerline
 {
\begin{tabular}{lrcl}
\hline
\hline
HJD$-$2~400~000 &  No. of frames  & Quality$^{{a}}$ & Telescope\\
\hline
54~217.3745-.5945 & 305 & 2 & RCC\\
54~220.4249-.4670 &  55 & 3 & RCC\\
54~221.3889-.5685 & 250 & 3 & RCC\\
54~222.3767-.5986 & 310 & 2 & RCC\\
54~223.3726-.5865 & 300 & 2 & RCC \\
54~242.3355-.5162 & 202 & 2 & RCC \\
54~244.3418-.3808 &  48 & 3 & RCC \\
54~245.3444-.5280 & 223 & 2 & RCC \\
54~245.3971-.6290 & 211 & 1 &IAC80\\
54~248.3915-.6535 & 165 & 1 &IAC80\\
54~249.4283-.6746 & 250 & 1 &IAC80\\
54~250.4068-.6728 & 270 & 1 &IAC80\\
54~251.4152-.6580 & 224 & 1 &IAC80\\
\hline
\end{tabular}}
\medskip
$^{{a}}$ The quality of the night is characterized by the extinction coefficient~$k'_V$ in units 
$V$~mag~${\rm (air mass)}^{-1}$: 
1: stable and $k'_V<0.25$, 
2: stable and $0.25\leq k'_V\leq 0.5$,
3: $k'_V>0.5$ or 
   $k'_V<0.5$ and unstable or
   $k'_V>0.5$ and interruptions because of clouds.
\end{table}