\begin{table}%t1
\caption{Ground-based observatories participating in the 2004--2005 observing season
of the WEBT campaign.}
\label{obs}
\small%\centerline
{
\begin{tabular}{l r c r }
\hline\hline
Observatory    & Tel. size     & Bands                & $N_{\rm obs}$\\
\hline
SAO RAS (RATAN)& 600 m$^a$     & 2.3, 4.8, 7.7,      & 33  \\
               &               & 11.1, 21.7 GHz      &     \\
Mets\"ahovi    & 14 m          & 37 GHz              & 142 \\
Noto           & 32 m          & 5, 8, 22 GHz        &  56 \\
Medicina       & 32 m          & 5, 8 GHz            &  23 \\
Effelsberg     & 100 m         & 4.9, 10.5 GHz       &  68 \\
UMRAO          & 26 m          & 4.8, 8.0, 14.5 GHz  & 112 \\
Pico Veleta    & 30 m          & 1, 2, 3 mm          &  18 \\
Campo Imperatore & 110 cm      & $J, H, K$           & 154 \\
Bohyunsan      & 180 cm        & $V, R, I$           & 126 \\
Mt. Maidanak   & 150 cm        & $U, B, V, R, I$     & 733 \\
Abastumani     &  70 cm        & $R$                 & 328 \\
Crimean        &  70 cm        & $B, V, R, I$        & 100 \\
Skinakas       & 130 cm        & $B, V, R, I$        &  83 \\
Tuorla         & 103 cm        & $R$                 &  20 \\
Armenzano      &  40 cm        & $B, V, R, I$        &  87 \\
Michael Adrian & 120 cm        & $R$                 &  48 \\
Asiago         & 182 cm        & $B, V, R, I$        &  38 \\
Torino         & 105 cm        & $R, I$              &  20 \\
Roque (KVA)    &  35 cm        & $R$                 &  69 \\
Roque (NOT)    & 256 cm        & $U, B, V, R, I$     &  24 \\
Roque (TNG)    & 358 cm        & $U, B, V, R, I$     &  10 \\
CASLEO         & 215 cm        & $B, V, R, I$        & 108 \\
La Silla (NTT) & 358 cm        & $R$                 &   5 \\
Boltwood       &  40 cm        & $R$                 & 129 \\
Bell           &  60 cm        & $R$                 &  23 \\
Kitt Peak (RCT)& 130 cm        & $R$                 &  24 \\
Kitt Peak (WIYN)& 90 cm        & $B, V, R, I$        &  12 \\
\hline
Total          &               &                     & 2593\\
\hline
\end{tabular}}
\medskip
$^a$ Ring telescope.
\end{table}