\begin{table}%t7
%\centering
\par
\caption{\label{tab7}Variability of 00291+59 and a faint field star.}
\begin{tabular}{lcccccc}
\hline \hline \noalign{\smallskip}
Date   &\multicolumn{2}{c}{----- Field star -----}&\multicolumn{4}{c}{-------------------------- 00291+59 ------------------------}\\
&mean mag&1$\sigma$ range      &mean mag&1$\sigma$ range&Significance of variability&Variability level\tablefootmark{1}\\
\hline\noalign{\smallskip}
15 Aug. &$i'$ = 19.127&0.014&$i'$ = 18.016&0.043&3.2 $\sigma$&$43 \pm 14$\\
       &$r'$ = 19.172&0.029&$r'$ = 17.833&0.041&1.4 $\sigma$&$<$130    \\
16 Aug. &$i'$ = 19.121&0.028&$i'$ = 18.043&0.045&1.6 $\sigma$&$<$130    \\
       &$r'$ = 19.188&0.042&$r'$ = 17.954&0.048&1.2 $\sigma$&$<$170    \\
17 Aug. &$i'$ = 19.094&0.038&$i'$ = 18.447&0.086&2.3 $\sigma$&$86 \pm 38$\\
       &$r'$ = 19.144&0.070&$r'$ = 18.296&0.057&0.8 $\sigma$&$<$270    \\
18 Aug. &$i'$ = 19.109&0.033&$i'$ = 18.935&0.079&2.4 $\sigma$&$79 \pm 33$\\
19 Aug. &$i'$ = 19.118&0.032&$i'$ = 19.378&0.077&2.4 $\sigma$&$77 \pm 32$\\
25 Sep. &$i'$ = 19.139&0.023&$i'$ = 18.206&0.026&1.0 $\sigma$&$<$110    \\
29 Sep. &$i'$ = 19.140&0.030&$i'$ = 18.543&0.033&1.1 $\sigma$&$<$120    \\
\hline
\end{tabular}
\tablefoot{\tablefoottext{1}{The level of variability in milli-mag (when it is detected at the $>$2$\sigma$ level), or 3$\sigma$ upper limit.}}
\vspace*{-2.5mm}
\end{table}