\begin{table}%t2
\caption{\label{Tab:masers}Measured proper motions, in the infrared frame, of the maser stars used for astrometric alignment.}
\small%\centerline
 {
\begin{tabular}{lrrrrrr}
\hline
\hline
%&&&&&& \\[-8pt]
Name & RA [arcsec] & Dec [arcsec] & $v_{\rm RA}$ [mas~yr$^{-1}$] & $v_{\rm Dec}$ [mas~yr$^{-1}$] & $\Delta_{\rm radio,IR}$$v_{\rm RA}$ [mas~yr$^{-1}$] & $\Delta_{\rm radio,IR}$$v_{\rm Dec}$ [mas~yr$^{-1}$]\\
 \hline
IRS~15NE &  $1.226\pm0.015$ &  $11.327\pm0.024$ & $-1.51\pm0.15$  &
$-5.81\pm0.15$ & $-0.46\pm0.17$ &  $0.13\pm0.19$\\
IRS~7    &  $0.046\pm0.010$ &  $5.569\pm0.016$ &  $-0.05\pm0.23$  &
$-4.59\pm0.23$ & $-0.53\pm0.55$ & $1.07\pm0.59$\\
IRS~17   &  $13.143\pm0.019$ & $5.566\pm0.030$ &  $-1.70\pm0.12$ &
$-1.04\pm0.12$ & $0.09\pm1.09$ & $0.29\pm1.23$\\
IRS~10EE &  $7.688\pm0.012$ &  $4.220\pm0.020$ & $-0.40\pm0.18$ &
$-1.55\pm0.18$& $0.44\pm0.19$ & $-0.55\pm0.19$\\
IRS~28   &  $10.477\pm0.016$ &  $-5.825\pm0.026$ &  $1.62\pm0.23$ &
$-4.71\pm0.23$ & $0.38\pm0.44$ & $-0.57\pm0.48$\\
IRS~9    &  $5.672\pm0.013$  & $-6.335\pm0.021$  & $3.30\pm0.25$  &
$3.03\pm0.25$ & $-0.24\pm0.26$ & $-0.92\pm0.31$\\
IRS~12N  &  $-3.250\pm0.012$ & $-6.876\pm0.019$ &  $-1.62\pm0.22$ &
$-2.78\pm0.22$ & $0.56\pm0.24$ & $0.07\pm0.28$\\
\hline
\end{tabular}}
\medskip
Positions are given for 2004.44 as offsets from Sgr~A*, positive toward the north and east. Proper motions are given in milli-arcseconds per year, positive toward north and east. The last two columns list the differences between the radio \citep{Reid2007ApJ} and IR~proper motions.
\end{table}