\begin{table}%t3
%\centering
\par
\caption{Comparison of various astrometric studies involving CdC plate material.
\label{table:3}}
\begin{tabular}{llccl}
 \noalign{\smallskip}
 \hline\hline
 \noalign{\smallskip}
Reference         &  Machine  &  Precision     &  Accuracy   & $N_{\rm pl}$ \\
 \noalign{\smallskip}
 \hline
 \noalign{\smallskip}
\par
This paper        &  Scanner  &  $0\farcs18$   & $0\farcs20$ & 400 \\
Rappaport 2006    &  APM      &  $0\farcs15$   & $0\farcs20$ & 512 \\
Ortiz-Gil 1998    &  PDS      &  $0\farcs15$   & $0\farcs15$ & 1 \\
Geffert   1996    &  MAMA     &  $0\farcs15$   & $0\farcs20$ & 2 \\
 \hline
\end{tabular}
\end{table}