\begin{table}%t1
\caption{Residuals between datasets from different sources. These are given as 
$X_2-X_1$ where~$X$ is the studied variable from the data sources~1 and~2.\label{tab1}}
%\centerline
{\begin{tabular}{llllll}
\hline  \hline     
 X & S1 & S2 & $N$ & $m_X$ & $\sigma$  \\
 \hline
$\Delta_{VV}$ &$\mu_V(1)$ &$\mu_V(2)$ & 13 & --0.014 & 0.044 \\
$\Delta_{VJ}$ &d$VJ(1)$ &$dVJ(2)$ & 14 & 0.015  & 0.045 \\
$\Delta_{VK}$ &d$VK(1)$ &$dVK(2)$ & 14 & 0.015  & 0.047 \\
$\Delta_{BV}$ &IMP02+ & Gal94 &          21 & --0.003 & 0.028 \\
$\Delta_{VI}$ &IMP02+ & Gal94 &          15 & --0.019 & 0.034 \\
$\Delta_{BR}$ &IMP02+ & Pal90 &          18 & --0.010 & 0.030 \\
$\Delta_{UR}$ &IMP02+ & Pal90 &          18 & --0.010 & 0.065 \\ 
\hline
\end{tabular}}
\par
\smallskip
(1) Variable~$X$; (2), (3) sources S1, S2 with abbreviated keys: 
$\mu_V(1)$, $V$-profile from OHP frames; $\mu_V(2)$, $V$-profile from Gal94; 
d$VJ(1)$, $\Delta_{VJ}$ from 2MASS and OHP frames; d$VJ(2)$, $\Delta_{VJ}$ from 2MASS 
and Gal94 $V$-profiles; d$VK(1)$ and d$VK(2)$, same sources for $\Delta_{VK}$. Source 
IMP02 contains data from this reference and from miscellaneous OHP\protect frames; 
(4) $N$~number of data; (5) $m_X$ mean residual; (6) standard\protect deviation~$\sigma$. 
\end{table}