\begin{table}%t2
\caption{\label{secpar}{Observational parameters for neutron stars with two epochs of observations.} 
}
\par
%\centerline
 {
\begin{tabular}{@{} l   c  c  c     c  c   c  c  c  c @{}}
\hline\hline
Neutron star & $m_{\rm BD}$$^{a}$ & $m_{\rm 13Jup}$$^{a}$ &  $m_{\rm lim}$$^{b}$ & 
Epoch difference &
$r_{\rm proj}$$^{c}$ & refX$^{d}$ & refY$^{d}$ & Align$_X$$^{e}$ & Align$_Y$$^{e}$ \\
             & [mag] & [mag] & [mag] & [yr] & [AU] & [mas] & [mas] & +/-- & +/--\\
\hline
Geminga & 18.2 & 22.3 & 22.4 & 3.05 & 10~000 & 148.4 & 148.4  & + & {--} \\
RX~J0720.4-3125 &  19.0 & 23.0 & 22.9 & 2.95 & 20~000 & 147.7 & 147.7 &+ & -- \\
RX~J1856.6-3754 & 17.3 & 21.4 & 21.5 & 3.0 & 10~800 & 147.8 & 147.7 & + &+ \\
PSR~J1932+1059 & 21.5 & 23.5 & 21.5  &2.9, 3.9 &  see text & 147.5 & 147.3  & -- &+\\
\hline
\end{tabular}}
\par
\smallskip
$^{a}$ $m_{\rm BD}$  and $m_{\rm 13Jup}$ are the brightest $H$-band magnitudes expected for a brown dwarf companion or a gas planet of 13 Jupiter mass respectively (see also text); 
$^{b}$ $m_{\rm lim}$ is the magnitude limit reached in both epochs; 
$^{c}$ $r_{\rm proj}$ is the covered projected physical separations; 
$^{d}$  (refX, refY) are the pixel scale of the reference {\it ISAAC} image;
$^{e}$ reference image axes are roughly aligned with RA (X) and DEC (Y) to within 1 degree, although
sometimes with opposite direction (indicated by ``--'' instead of ``+'').   
\end{table}