\begin{table}
\caption{\label{wat_tab}Parameters of VLBA 22.2~GHz water maser features.}
\begin{tabular}{ccrcrrcrrr}
\hline \hline \noalign{\smallskip}
Feature &  $V_{\rm LSR}$ & \multicolumn{1}{c}{$F_{\rm peak}$}  & & \multicolumn{1}{c}{$\Delta x$} & \multicolumn{1}{c}{$\Delta y$} &  & \multicolumn{1}{c}{$V_{\rm x}$} & \multicolumn{1}{c}{$V_{\rm y}$} & \multicolumn{1}{c}{$\Delta|V|/|V| $} \\
        &  (km s$^{-1}$) & \multicolumn{1}{c}{(Jy beam$^{-1}$)} &  & \multicolumn{1}{c}{(mas)} & \multicolumn{1}{c}{(mas)} &  & \multicolumn{1}{c}{(km s$^{-1}$)} & \multicolumn{1}{c}{(km s$^{-1}$)} &                  \\
\hline
1   & 72.58 &202.89 (4)& & $  -64.38 \pm 0.10 $ & $  -60.45 \pm 0.11 $& &  $ -10.8 \pm 3.5$ & $  3.0 \pm 3.6$ & 31\% \\
2   & 78.48 &22.21  (3)& & $  437.05 \pm 0.11 $ & $   74.67 \pm 0.28 $& &  $  11.6 \pm 3.5$ & $-18.1 \pm6.3 $ & 26\% \\
3   & 79.32 &19.68  (3)& & $  437.16 \pm 0.10 $ & $   73.42 \pm 0.14 $& &  $  10.0 \pm 3.5$ & $ -0.0 \pm 5.0$ & 36\% \\
4   & 75.95 &15.70  (1)& & $  425.22 \pm 0.10 $ & $  159.39 \pm 0.12 $& &  $   9.4 \pm 3.4$ & $ -0.1 \pm 4.3$ & 37\% \\
5   & 73.21 &12.70  (1)& & $  -61.49 \pm 0.26 $ & $  -76.84 \pm 0.14 $& &  $ -22.3 \pm11.7$ & $-42.8 \pm 8.1$ & 19\% \\
6   & 79.32 & 9.44  (3)& & $  -60.71 \pm 0.08 $ & $  -77.23 \pm 0.09 $& &  $ -51.0 \pm 4.6$ & $-30.3 \pm 5.1$ & 8\% \\
7   & 78.26 & 9.21  (1)& & $  425.12 \pm 0.10 $ & $  158.45 \pm 0.13 $& &  $  10.5 \pm 3.6$ & $-26.0 \pm 4.5$ & 16\% \\
8   & 69.00 & 7.75  (1)& & $  -65.47 \pm 0.10 $ & $  -60.76 \pm 0.12 $& &         ...       &       ...       & ...  \\
9   & 66.47 & 5.14  (4)& & $  -66.17 \pm 0.13 $ & $  -60.82 \pm 0.12 $& &  $   3.4 \pm 4.2$ & $ -5.3 \pm 3.5$ & 60\% \\
10  & 61.83 & 5.08  (4)& & $  -53.18 \pm 0.10 $ & $  -54.25 \pm 0.12 $& &  $ -26.3 \pm 4.0$ & $ 3.5 \pm 4.1 $ & 15\% \\
11  & 77.63 & 5.08  (2)& & $  -59.60 \pm 0.12 $ & $  -77.20 \pm 0.12 $& &  $   1.8 \pm 7.0$ & $-45.5 \pm 8.3$ & 18\% \\
12  & 72.57 & 4.92  (1)& & $  -65.17 \pm 0.10 $ & $  -60.67 \pm 0.14 $& &         ...       &       ...       & ...  \\
13  & 76.58 & 4.82  (4)& & $  425.18 \pm 0.10 $ & $  158.79 \pm 0.11 $& &  $   5.9 \pm 3.3$ & $ -3.6 \pm 4.4$ & 53\% \\
14  & 66.05 & 4.76  (3)& & $  -53.84 \pm 0.10 $ & $  -54.65 \pm 0.11 $& &  $ -22.3 \pm 3.5$ & $ 4.1 \pm 4.2 $ & 16\% \\
15  & 76.37 & 4.17  (3)& & $  -53.29 \pm 0.09 $ & $  -30.59 \pm 0.13 $& &         ...       &       ...       & ...  \\
16  & 72.58 & 3.86  (1)& & $  -62.93 \pm 0.09 $ & $  -60.06 \pm 0.11 $& &         ...       &       ...       & ...  \\
17  & 77.21 & 3.06  (4)& & $  -61.51 \pm 0.08 $ & $  -78.62 \pm 0.09 $& &         ...       &       ...       & ...  \\
18  & 74.26 & 2.80  (2)& & $  -59.39 \pm 0.11 $ & $  -77.00 \pm 0.14 $& &  $  -4.2 \pm 7.0$ & $-46.0 \pm 9.2$ & 20\% \\
19  & 78.90 & 2.54  (4)& & $  -55.73 \pm 0.11 $ & $ -102.53 \pm 0.13 $& &         ...       &       ...       & ...  \\
20  & 75.10 & 2.37  (3)& & $   32.66 \pm 0.08 $ & $  -14.48 \pm 0.09 $& &         ...       &       ...       & ...  \\
21  & 79.74 & 2.27  (3)& & $  420.54 \pm 0.10 $ & $  126.25 \pm 0.12 $& &  $   5.4 \pm 3.6$ & $ -2.5 \pm 3.7$ & 62\% \\
22  & 56.99 & 2.18  (1)& & $  -52.03 \pm 0.10 $ & $  -53.90 \pm 0.13 $& &         ...       &       ...       & ...  \\
23  & 78.69 & 2.10  (1)& & $  -52.17 \pm 0.15 $ & $  -31.90 \pm 0.18 $& &         ...       &       ...       & ...  \\
24  & 71.52 & 1.95  (2)& & $          0       $ & $         0        $& &  $       0      $ & $      0      $ & ...  \\
25  & 78.26 & 1.72  (4)& & $  435.51 \pm 0.10 $ & $   77.83 \pm 0.13 $& &  $   6.0 \pm 3.6$ & $ -3.4 \pm 4.0$ & 54\% \\
26  & 65.63 & 1.64  (1)& & $  -66.53 \pm 0.14 $ & $  -60.98 \pm 0.11 $& &  $ -29.5 \pm 4.7$ & $12.9 \pm 4.1 $ & 14\% \\
27  & 68.36 & 1.52  (1)& & $  -64.97 \pm 0.13 $ & $  -60.60 \pm 0.12 $& &         ...       &       ...       & ...  \\
28  & 81.21 & 1.43  (3)& & $  -62.98 \pm 0.08 $ & $  -77.14 \pm 0.09 $& &         ...       &       ...       & ...  \\
29  & 79.95 & 1.41  (4)& & $  -63.87 \pm 0.13 $ & $ -163.86 \pm 0.10 $& &  $ -18.6 \pm 7.3$ & $-35.6 \pm 5.6$ & 15\% \\
30  & 78.05 & 1.29  (1)& & $  -49.12 \pm 0.14 $ & $ -160.46 \pm 0.11 $& &  $  -6.5 \pm 9.1$ & $-14.4 \pm10.9$ & 67\% \\
31  & 72.37 & 1.09  (1)& & $  -62.09 \pm 0.09 $ & $  -76.67 \pm 0.11 $& &         ...       &       ...       & ...  \\
32  & 80.37 & 0.76  (4)& & $  -57.43 \pm 0.09 $ & $ -162.26 \pm 0.11 $& &         ...       &       ...       & ...  \\
33  & 79.53 & 0.75  (3)& & $  -32.44 \pm 0.10 $ & $  -29.99 \pm 0.12 $& &  $  -4.5 \pm 3.4$ & $-12.4 \pm 3.7$ & 28\% \\
34  & 80.79 & 0.71  (1)& & $  425.21 \pm 0.10 $ & $  158.23 \pm 0.11 $& &         ...       &       ...       & ...  \\
35  & 72.16 & 0.67  (1)& & $  -60.58 \pm 0.10 $ & $  -77.28 \pm 0.11 $& &         ...       &       ...       & ...  \\
36  & 78.48 & 0.59  (2)& & $  -49.46 \pm 0.08 $ & $ -161.70 \pm 0.13 $& &         ...       &       ...       & ...  \\
37  & 66.89 & 0.56  (1)& & $  -66.88 \pm 0.12 $ & $  -61.05 \pm 0.11 $& &         ...       &       ...       & ...  \\
38  & 80.58 & 0.55  (1)& & $  437.41 \pm 0.10 $ & $   67.80 \pm 0.15 $& &  $  11.4 \pm 7.2$ & $ -6.8 \pm10.8$ & 63\% \\
39  & 75.32 & 0.49  (2)& & $ -548.55 \pm 0.09 $ & $ -314.11 \pm 0.11 $& &         ...       &       ...       & ...  \\
40  & 79.53 & 0.48  (2)& & $  -49.38 \pm 0.09 $ & $ -162.86 \pm 0.17 $& &         ...       &       ...       & ...  \\
41  & 76.79 & 0.44  (2)& & $ -548.30 \pm 0.09 $ & $ -314.13 \pm 0.09 $& &         ...       &       ...       & ...  \\
42  & 79.32 & 0.43  (4)& & $ -293.32 \pm 0.08 $ & $ -100.02 \pm 0.08 $& &         ...       &       ...       & ...  \\
43  & 67.94 & 0.42  (1)& & $  -53.79 \pm 0.09 $ & $  -54.67 \pm 0.11 $& &         ...       &       ...       & ...  \\
44  & 80.58 & 0.39  (1)& & $ -287.44 \pm 0.10 $ & $  -98.35 \pm 0.12 $& &  $ -18.6 \pm 3.5$ & $ -1.5 \pm 3.8$ & 19\% \\
45  & 88.59 & 0.38  (1)& & $  -64.55 \pm 0.13 $ & $ -162.29 \pm 0.12 $& &  $  -7.6 \pm 8.2$ & $-34.9 \pm10.7$ & 30\% \\
46  & 63.94 & 0.38  (4)& & $  -54.44 \pm 0.11 $ & $  -54.30 \pm 0.09 $& &         ...       &       ...       & ...  \\
47  & 80.16 & 0.36  (1)& & $  440.10 \pm 0.10 $ & $   58.11 \pm 0.16 $& &  $  18.7 \pm 7.1$ & $-26.3 \pm10.6$ & 30\% \\
48  & 62.47 & 0.35  (4)& & $  -64.15 \pm 0.09 $ & $  -60.07 \pm 0.09 $& &         ...       &       ...       & ...  \\
49  & 79.32 & 0.33  (3)& & $ -293.50 \pm 0.10 $ & $ -100.37 \pm 0.12 $& &  $  -8.8 \pm 3.5$ & $ -8.5 \pm 4.0$ & 31\% \\
50  & 78.26 & 0.32  (2)& & $  -61.72 \pm 0.08 $ & $  -78.38 \pm 0.17 $& &         ...       &       ...       & ...  \\
51  & 62.25 & 0.31  (3)& & $  -54.39 \pm 0.10 $ & $  -54.57 \pm 0.10 $& &         ...       &       ...       & ...  \\
52  & 69.42 & 0.31  (1)& & $  -40.40 \pm 0.10 $ & $   -7.34 \pm 0.11 $& &         ...       &       ...       & ...  \\
53  & 79.74 & 0.31  (1)& & $  284.39 \pm 0.10 $ & $  -55.26 \pm 0.12 $& &  $   0.2 \pm 4.0$ & $-18.3 \pm 4.9$ & 27\% \\
54  & 77.21 & 0.30  (1)& & $  -58.94 \pm 0.10 $ & $  -77.13 \pm 0.13 $& &         ...       &       ...       & ...  \\
55  & 80.16 & 0.28  (1)& & $  437.51 \pm 0.10 $ & $   67.22 \pm 0.20 $& &         ...       &       ...       & ...  \\
56  & 76.16 & 0.27  (1)& & $ -103.16 \pm 0.10 $ & $ -150.22 \pm 0.12 $& &         ...       &       ...       & ...  \\
57  & 89.43 & 0.26  (1)& & $  -49.16 \pm 0.12 $ & $ -158.89 \pm 0.12 $& &         ...       &       ...       & ...  \\
58  & 71.95 & 0.23  (1)& & $  -67.77 \pm 0.10 $ & $  -61.37 \pm 0.11 $& &         ...       &       ...       & ...  \\
59  & 80.58 & 0.22  (4)& & $  -82.16 \pm 0.08 $ & $ -104.88 \pm 0.09 $& &         ...       &       ...       & ...  \\
60  & 77.42 & 0.21  (2)& & $ -546.43 \pm 0.08 $ & $ -314.43 \pm 0.10 $& &         ...       &       ...       & ...  \\
61  & 70.68 & 0.21  (2)& & $  -65.69 \pm 0.08 $ & $  -60.78 \pm 0.09 $& &         ...       &       ...       & ...  \\
62  & 77.21 & 0.20  (1)& & $  418.75 \pm 0.10 $ & $   92.99 \pm 0.12 $& &  $   5.8 \pm 3.8$ & $ -1.6 \pm 4.7$ & 64\% \\
63  & 70.05 & 0.20  (3)& & $   27.36 \pm 0.09 $ & $  -15.57 \pm 0.12 $& &         ...       &       ...       & ...  \\
64  & 59.51 & 0.19  (3)& & $  -57.57 \pm 0.09 $ & $  -63.38 \pm 0.11 $& &         ...       &       ...       & ...  \\
65  & 75.74 & 0.17  (3)& & $ -549.28 \pm 0.09 $ & $ -314.97 \pm 0.11 $& &         ...       &       ...       & ...  \\
66  & 81.63 & 0.16  (1)& & $  -70.96 \pm 0.10 $ & $  -88.63 \pm 0.13 $& &         ...       &       ...       & ...  \\
67  & 79.74 & 0.16  (3)& & $  -53.11 \pm 0.09 $ & $ -105.70 \pm 0.10 $& &         ...       &       ...       & ...  \\
68  & 70.89 & 0.16  (4)& & $  -51.85 \pm 0.09 $ & $  -73.26 \pm 0.10 $& &         ...       &       ...       & ...  \\
69  & 74.68 & 0.15  (4)& & $   31.19 \pm 0.09 $ & $  -13.67 \pm 0.09 $& &         ...       &       ...       & ...  \\
70  & 70.89 & 0.14  (4)& & $  -38.58 \pm 0.09 $ & $  -53.28 \pm 0.09 $& &         ...       &       ...       & ...  \\
71  & 68.57 & 0.14  (4)& & $  -53.90 \pm 0.09 $ & $  -54.56 \pm 0.09 $& &         ...       &       ...       & ...  \\
72  & 67.31 & 0.13  (1)& & $  -63.71 \pm 0.10 $ & $  -60.09 \pm 0.14 $& &         ...       &       ...       & ...  \\
73  & 75.10 & 0.13  (1)& & $ 442.20  \pm 0.10 $ & $  98.34  \pm 0.14 $& &         ...       &       ...       & ...  \\
74  & 75.74 & 0.12  (1)& & $  -51.19 \pm 0.10 $ & $  -68.44 \pm 0.16 $& &         ...       &       ...       & ...  \\
75  & 66.05 & 0.11  (3)& & $ -541.56 \pm 0.10 $ & $ -291.69 \pm 0.12 $& &         ...       &       ...       & ...  \\
76  & 79.53 & 0.11  (4)& & $  -51.08 \pm 0.09 $ & $ -160.20 \pm 0.10 $& &         ...       &       ...       & ...  \\
77  & 73.21 & 0.10  (1)& & $  -67.84 \pm 0.10 $ & $  -61.58 \pm 0.15 $& &         ...       &       ...       & ...  \\
78  & 81.00 & 0.09  (4)& & $  412.27 \pm 0.09 $ & $  171.84 \pm 0.10 $& &         ...       &       ...       & ...  \\
79  & 73.84 & 0.09  (2)& & $  -68.81 \pm 0.09 $ & $  -61.71 \pm 0.15 $& &         ...       &       ...       & ...  \\
80  & 76.16 & 0.09  (3)& & $ -540.64 \pm 0.09 $ & $ -267.93 \pm 0.14 $& &         ...       &       ...       & ...  \\
81  & 77.21 & 0.09  (1)& & $  419.08 \pm 0.10 $ & $  168.99 \pm 0.13 $& &         ...       &       ...       & ...  \\
82  & 71.94 & 0.09  (3)& & $  -99.30 \pm 0.09 $ & $ -173.21 \pm 0.11 $& &         ...       &       ...       & ...  \\
83  & 69.42 & 0.09  (1)& & $  -68.13 \pm 0.11 $ & $  -61.87 \pm 0.15 $& &  $ -26.8 \pm 8.2$ & $ 8.0 \pm 10.6$ & 30\% \\
84  & 76.58 & 0.08  (1)& & $  -52.05 \pm 0.10 $ & $  -68.04 \pm 0.16 $& &         ...       &       ...       & ...  \\
85  & 63.73 & 0.08  (2)& & $  -53.41 \pm 0.09 $ & $  -54.35 \pm 0.14 $& &         ...       &       ...       & ...  \\
86  & 85.85 & 0.07  (4)& & $   -4.96 \pm 0.09 $ & $ -151.45 \pm 0.12 $& &         ...       &       ...       & ...  \\
\hline \noalign{\smallskip}
\multicolumn{10}{c}{Reference Feature: Absolute position \& Proper motion}\\
Feature & \multicolumn{3}{c}{RA(J2000)} & \multicolumn{3}{c}{ Dec(J2000) } & \multicolumn{1}{c}{$V_{\rm x}$} & \multicolumn{1}{c}{$V_{\rm y}$} & \multicolumn{1}{c}{$\Delta|V|/|V| $} \\
 & \multicolumn{3}{c}{(h m s)} & \multicolumn{3}{c}{(\degr $'$ $''$)} & \multicolumn{1}{c}{(km s$^{-1}$)} & \multicolumn{1}{c}{(km s$^{-1}$)}& \\
\hline
24 &\multicolumn{3}{c}{18:34:40.28950 $\pm$ 0.00010}&\multicolumn{3}{c}{$-$09:00:38.2044 $\pm$ 0.0015}&$ 5.3 \pm 8.6 $&$ 21.3 \pm 8.6 $& 39\% \\
\hline
\end{tabular}
\tablefoot{For each identified feature, the label (given in Col.~1) increases with decreasing brightness. Columns~2 and~3 report the LSR velocity and brightness of the brightest spot (for the epoch specified by the number in brackets). Columns~4 and~5 give the position offset relative to the feature~\#24, in the east and north directions, respectively. Columns~6 and~7 report the projected components of the feature proper motion relative to the feature~\#24, along the east and north directions, respectively. Column~8 shows the relative error of the proper motion amplitude.
The absolute position and proper motion of the reference feature~\#24 are reported at the bottom of the table.}
\end{table}