\begin{table}%t4
\caption{\label{apcotab}Aperture corrections.}         
%\centerline
{         
\begin{tabular}{l c c c c c}   
\hline\hline   
File name & Filter & CCD chip & Aperture correction  \\  
\hline
r556732  & $y$ & 1/2/3/4 & 1.265/1.266/1.278/1.266  \\
r556737  & $b$ & 1/2/3/4 & 1.273/1.262/1.274/1.256  \\
r556748  & $v$ & 1/2/3/4 & 1.195/1.191/1.164/1.168  \\
r556754  & $u$ & 1/2/3/4 & 1.171/1.161/1.135/1.148  \\
r556882  & $b$ & 1/2/3/4 & 1.269/1.264/1.259/1.240  \\
r556887  & $y$ & 1/2/3/4 & 1.162/1.166/1.162/1.155  \\
r556893  & $v$ & 1/2/3/4 & 1.268/1.264/1.223/1.238  \\
r556898  & $u$ & 1/2/3/4 & 1.378/1.366/1.312/1.343  \\
r556899  & $u$ & 1/2/3/4 & 1.384/1.362/1.316/1.352  \\
r556997  & $y$ & 1/2/3/4 & 1.254/1.261/1.254/1.244  \\
r557004  & $b$ & 1/2/3/4 & 1.212/1.203/1.204/1.188  \\
r557009  & $v$ & 1/2/3/4 & 1.382/1.382/1.336/1.356  \\
r557018  & $u$ & 1/2/3/4 & 1.209/1.198/1.160/1.185  \\
r557019  & $u$ & 1/2/3/4 & 1.335/1.322/1.282/1.308  \\
\hline
\end{tabular}}\medskip
\par
Column~1 lists the file name for the image as named by the observing and archiving system on the Isaac Newton Telescope. Column~2 lists the filter. Column~3 lists the CCD chip number and Col.~4 the aperture correction for each CCD in the same order as in Col.~3.
\end{table}