\begin{table}%t1
%\centering
\par
%\tabcolsep 0.20truecm
\caption{Journal of photometric observations of NGC~1901 and standard star
         fields, together with calibration coefficients (2005, November~29).\label{tab1}}
 {\begin{tabular}{ccccc}
\hline\hline
\multicolumn{1}{c}{Field}         &
\multicolumn{1}{c}{Filter}        &
\multicolumn{1}{c}{Exposure time} &
\multicolumn{1}{c}{Seeing}        &
\multicolumn{1}{c}{Airmass}       \\
 &  \multicolumn{3}{c}{[sec.]} & [$\prime\prime$]  \\
\hline
NGC 1901        & $U$ & 1200, 60, 5 & 1.1 & 1.150--1.280 \\
                & $B$ &  900, 30, 3 & 1.0 & 1.150--1.280 \\
                & $V$ &  600, 30, 1 & 1.0 & 1.150--1.280 \\
                & $I$ &  600, 30, 1 & 1.0 & 1.150--1.280 \\
\hline
TPhoenix        & $U$ & 180, 200   & 1.0 & 1.024, 1.444 \\
                & $B$ &  90, 120   & 1.1 & 1.023, 1.447 \\
                & $V$ &  20, 30    & 1.1 & 1.024, 1.450 \\
                & $I$ &  40, 40    & 1.1 & 1.022, 1.452 \\
\hline
PG 0231+006     & $U$ & 200, 240   & 1.1 & 1.291, 1.801 \\
                & $B$ &  60, 90    & 1.1 & 1.293, 1.807 \\
                & $V$ &  40, 40    & 1.1 & 1.296, 1.809 \\
                & $I $&  40, 30    & 1.1 & 1.294, 1.810 \\
\hline
Rubin~149       & $U$ & 180, 240   & 1.0 & 1.311, 1.651 \\
                & $B$ &  90, 120   & 1.1 & 1.316, 1.649 \\
                & $V$ &  30, 40    & 1.0 & 1.318, 1.647 \\
                & $I$ &  40, 40    & 1.0 & 1.313, 1.643 \\
\hline
Calibration     & \multicolumn {3}{l}{$u_1 = +3.285 \pm 0.004$} \\
coefficients    & \multicolumn {3}{l}{$u_2 = +0.032 \pm 0.006$} \\
                & \multicolumn {3}{l}{$u_3 = +0.46$}            \\
                & \multicolumn {3}{l}{$b_1 = +2.188 \pm 0.004$} \\
                & \multicolumn {3}{l}{$b_2 = -0.160 \pm 0.006$} \\
                & \multicolumn {3}{l}{$b_3 = +0.27$}            \\
                & \multicolumn {3}{l}{$v_{1bv} = +2.188 \pm 0.014$} & \multicolumn {1}{l}{$i_1 = +2.789 \pm 0.044$} \\
                & \multicolumn {3}{l}{$v_{2bv} = +0.017 \pm 0.018$} & \multicolumn {1}{l}{$i_2 = +0.021 \pm 0.043$} \\
                & \multicolumn {3}{l}{$v_3 = +0.12$}                & \multicolumn {1}{l}{$i_3 = +0.06$}            \\
                & \multicolumn {3}{l}{$v_{1vi} = +2.188 \pm 0.016$}  \\
                & \multicolumn {3}{l}{$v_{2vi} = +0.013 \pm 0.016$}  \\
\hline
\end{tabular}}
\end{table}