\begin{table}%t1 \caption{\label{tab1}Summary of VERA observations in R~Aqr. We give the relative positions of the central star with respect to the J2000~Hipparcos coordinates (and their uncertainties at 2$\sigma$-level).} %\centering \small \begin{tabular}{lcccccl} \hline\hline \noalign{\smallskip} Date & \multicolumn{2}{c}{Star's relative coordinates (mas)} & \multicolumn{3}{c}{Number of spots} & Comments \\ & $\Delta$(AR) & $\Delta$(Dec) & $v=1$ $J$ = 1--0 & $v=2$ $J$ = 1--0 & coincident $v=1,2$ & \\ \hline 23 Dec. 2004 & 135.3 (4.2) & --133.1 (1.4) & 7 & 41 & 1 (1) & \\ 27 Sep. 2005 & 161.4 (0.5) & --154.9 (0.8) & 4 & 76 & 0 (0) & \\ 23 Nov. 2005 & 164.5 (0.3) & --160.7 (0.5) & 79 & 77 & 3 (11) & \\ 24 Dec. 2005 & 166.4 (0.3) & --162.4 (0.6) & 66 & 75 & 11 (16) & \\ 14 Feb. 2006 & 172.7 (0.3) & --165.2 (0.5) & 116 & 157 & 0 (1) & \\ 04 Mar. 2006 & 175.1 (0.3) & --165.7 (0.5) & 56 & 196 & 0 (5) & \\ 08 May 2006 & -- & -- & & & -- & no absolute astrometry \\ 11 Jul. 2006 & -- & -- & & & -- & no absolute astrometry \\ 26 Jul. 2006 & -- & -- & & & -- & no absolute astrometry \\ 30 Aug. 2006 & 195.7 (1.0) & --181.5 (0.8) & 24 & 31 & 0 (0) & \\ 13 Oct. 2006 & 196.6 (2.4) & --188.4 (1.0) & 41 & 73 & 4 (6) & poor fitting\\ \hline \end{tabular} \tablefoot{The spot coincidences have been estimated for spatial distances less than~1/3 (and than~2/3) of the~beam.} \end{table}