\begin{table}%t2
\caption{Mean differences between variable/comparison~2 and comparison~1 star per season and per filter.}\label{tab:means}
%\centering
\par
\begin{tabular}{ccccccc}
\hline  \hline
 Data type & Campaign & No. & Filter $u$ & Filter $v$ & Filter $b$ & Filter $y$ \struutup \\
 &&& Mean (St. dev.)& Mean (St. dev.) & Mean (St. dev.) & Mean (St. dev.) \struutdown \\
\hline
 V--C1  & OAN 2002 & 429 &  --2.2251 (0.022) & --2.2572 (0.014) &  --1.6962 (0.012) &  --1.3136 (0.011)\struutup \\
C2--C1  & OAN 2002 & 420 &  --1.1529 (0.015) & --0.7820 (0.006) &  --0.3107 (0.005) &  --0.0353 (0.004)\\
\cline{2-7}
 V--C1  & OSN 2002 & 748 &  --2.2205 (0.011) & --2.2608 (0.009) &  --1.7454 (0.008) &  --1.3279 (0.007)\\
C2--C1  & OSN 2002 & 750 &  --1.0932 (0.009) & --0.7351 (0.004) &  --0.3120 (0.003) &  --0.0424 (0.004)\\
\cline{2-7}
 V--C1  & OAN 2003 & 269 &  --2.2216 (0.016) & --2.2835 (0.011) &  --1.7666 (0.010) &  --1.3264 (0.008)\\
C2--C1  & OAN 2003 & 269 &  --1.1408 (0.011) & --0.7843 (0.002) &  --0.3155 (0.002) &  --0.0340 (0.002)\\
\cline{2-7}
 V--C1  & OSN 2004 & 144 &  --2.2317 (0.010) & --2.2697 (0.008) &  --1.7509 (0.007) &  --1.3336 (0.006)\\
C2--C1  & OSN 2004 & 144 &  --1.1052 (0.011) & --0.7407 (0.003) &  --0.3160 (0.004) &  --0.0459 (0.003)\struutdown \\
\hline
\end{tabular}
\end{table}