\begin{table}%t6
\center
\caption{Average parameters for all photometric solutions and
constraining the sample to the 3-parameter fits. The table gives:
in Col.~1 the passband/filter combination; in Col.~2 the median
zeropoint in Vega System ($Zp$) including solutions obtained from fits with an
arbitrary number of free parameters; in Col.~3 the scatter computed
from the distribution of zeropoints (rms); in Col.~4 the largest
offset of a night calibration relative to the median reported,
$(\Delta Zp)_{\max}$; in Cols.~5--7 the same as in the three previous
columns, except that now the estimate of the median is computed using
only 3-parameter fits.}
\label{tab:zpquality}\small
\begin{tabular}{ccccccc}
\hline\hline
Passband &  $Zp$ & rms & $(\Delta Zp)_{\max}$ & $Zp$ & rms & $(\Delta {\rm Z}p)_{\max}$  \\
\hline
U\#877&22.02&0.27&$-$0.72&22.06&0.22&$-$0.68 \\
U\#841&21.58&0.08&0.11&--&--& -- \\
B\#842&24.64&0.08&$-$0.21&24.58&0.05&$-$0.27 \\
V\#843&24.18&0.08&0.16&24.23&0.1&0.21 \\
R\#844&24.52&0.08&-0.17&24.49&0.09&$-$0.2 \\
I\#879&23.34&0.02&0.02&23.35&0.0&0.03 \\
I\#845&23.14&0.11&$-$0.3&23.18&0.13&$-$0.26 \\
\hline
\end{tabular}
\end{table}