\begin{table}%T2
  %\centering
\par
 \caption{Integration times and disk magnitude limits. The latter ones
           were determined with artificial disks of the sizes shown in 
           this table. No disk was found down to the given surface 
           brightness. The reduction routine has a lower performance for 
           stars in clusters and a determination of brightness limits
           was sometimes not possible. These cases are indicated with "--''. 
           Estimated errors for the given magnitudes are $\pm$0.2~mag. 
           The disk brightness limit as a function of disk radius was 
           studied in more detail for the targets HD~4208, HD~33636 and 
           HD~217107 with further radii 1.0, 1.8, 2.5, 3.3, 4.0 and~4.8\arcsec~(cf.~Fig.~\ref{figure:mag}). Disks with radii 
           $>$~5.0\arcsec~are too big for a detection with our 
           software (since they would cover large parts of the detector,
           which makes them unphysical anyway). The {\it S/N}-ratio is 
           the {\it S/N}~per~pixel and was calculated as described in
           Sect.~\ref{sect:discussion}.\label{table:results}} 
  \begin{tabular}{lcrrrlr}
    \hline
    \hline
    Star & Filter & $t_{{\rm exp}}$ & $R_{{\rm disk}}$ & Sep. 
         & Limit             & {\it S/N}   \\
         &        &       [min]        &        [AU]         & [$\arcsec$] 
         & [mag/$\arcsec^2$] &       \\
    \hline
    HD 142
    &  $J$     &     5    &   50       &   2.5   &  14.2  &  4.1    \\
    &        &          &   75       &   3.7   &  16.7  &  4.3    \\
    &        &          &   100      &   4.9   &  15.0  &  3.5    \\
    &  $H$     &     5    &   50       &   2.5   &  14.9  &  3.5    \\
    &        &          &   75       &   3.7   &  17.1  &  3.5    \\
    &        &          &   100      &   4.9   &  16.4  &  2.5    \\
    HD 1237
    &  $J$     &     5    &   50       &   2.9   &  16.0  &  3.6    \\
    (=GJ 3021)
    &        &          &   75       &   4.3   &  16.7  &  2.7    \\
    &  $H$     &     7    &   50       &   2.9   &  14.6  &  4.0    \\
    &        &          &   75       &   4.3   &  15.6  &  3.1    \\
    HD 4208
    &  $H$     &     8    &   34       &   1.0   &  13.1  &         \\
    &        &          &   50       &   1.5   &  14.6  &  2.5    \\
    &        &          &   59       &   1.8   &  15.6  &         \\
    &        &          &   75       &   2.2   &  15.9  &  2.7    \\
    &        &          &   85       &   2.5   &  16.4  &         \\
    &        &          &   100      &   3.0   &  16.4  &  2.1    \\
    &        &          &   110      &   3.3   &  17.1  &         \\
    &        &          &   136      &   4.0   &  17.1  &         \\
    &        &          &   161      &   4.8   &  17.7  &         \\
    HD 23079
    &  $J$     &     5    &   50       &   1.5   &  13.5  &  2.3    \\
    &        &          &   75       &   2.2   &  15.2  &  2.6    \\
    &        &          &   100      &   2.9   &  16.0  &  2.4    \\
    HD 33636
    &  $J$     &     5    &   29       &   1.0   &  13.5  &         \\
    &        &          &   50       &   1.8   &  15.0  &  2.6    \\
    &        &          &   72       &   2.5   &  16.7  &         \\
    &        &          &   75       &   2.6   &  16.7  &  3.1    \\
    &        &          &   93       &   3.3   &  17.5  &         \\
    &        &          &   100      &   3.5   &  17.5  &  2.6    \\
    &        &          &   115      &   4.0   &  17.5  &         \\
    &        &          &   136      &   4.8   &  17.5  &         \\
    HD 52265
    &  $J$     &    10    &   50       &   1.8   &  14.2  &  2.6    \\
    &        &          &   75       &   2.7   &  16.0  &  2.6    \\
    &        &          &   100      &   3.6   &  16.0  &  2.3    \\
    HD 82943
    &  $H$     &     2    &   25       &   0.9   &  11.9  &  1.6    \\
    &        &          &   50       &   1.8   &  14.6  &  4.0    \\
    &        &          &   75       &   2.7   &  16.3  &  6.0    \\
    HD 102647
    &  $H$     &     2    &   25       &   2.3   &  13.1  &  3.6    \\
    (=$\beta$ Leo)
    &        &          &   50       &   4.5   &  14.6  &  5.1    \\
 \hline
    HD 134987
    &  $J$     &     2    &   25       &   1.0   &  13.2  &  1.8    \\
    &        &          &   50       &   2.0   &  15.9  &  3.8    \\ 
    &        &          &   75       &   3.0   &  15.9  &  4.9    \\
    &  $H$     &     2    &   25       &   1.0   &  12.3  &  1.8    \\
    &        &          &   50       &   2.0   &  13.8  &  3.2    \\
    &        &          &   75       &   3.0   &  15.3  &  3.7    \\
    HD 139664
    &  $J$     &     3    &   25       &   1.5   &  13.6  &  2.8    \\
    &        &          &   50       &   2.9   &  15.1  &  6.6    \\
 &        &          &   75       &   4.3   &  15.9  &  9.1    \\ 
    HD 141569 
    &  $H$     &     5    &   500      &   5.0   &  14.8  &  5.2    \\
    &        &          &   1000     &  10.0   &  15.5  &  3.7    \\
    & $K_{\rm s}$
             &     5    &   500      &   5.0   &  14.5  &  4.3    \\
    &        &          &   1000     &  10.0   &  15.3  &  2.5    \\
    HD 155448
    &  $H$     &    10    &   1000     &   2.0   &  --     &  --      \\
    HD 158643
    &  $H$     &     5    &   500      &   3.9   &  13.7  &  --      \\
    (=51 Oph)
    &        &          &   1000     &   8.0   &  16.2  &  --      \\   
    HD 160691 
    &  $J$     &     2    &   25       &   1.7   &  12.9  &  2.8    \\
    &        &          &   50       &   3.3   &  15.1  &  5.1    \\ 
    &        &          &   75       &   4.9   &  15.1  &  5.1    \\ 
    &  $H$     &     3    &   25       &   1.7   &  13.1  &  2.8    \\
    &        &          &   50       &   3.3   &  14.6  &  5.8    \\
    &        &          &   75       &   4.9   &  14.6  &  6.5    \\
    HD 163296
    &  $H$     &     6    &   500      &   4.1   &  15.5  &  3.1    \\
    &        &          &   1000     &   8.0   &  16.2  &  --      \\
    HD 179949
    &  $H$     &     1    &   25       &   1.0   &  12.6  &  2.0    \\
    &        &          &   50       &   1.9   &  15.3  &  3.8    \\
    &        &          &   75       &   2.8   &  16.3  &  5.5    \\
    HD 207129
    &  $J$     &     3    &   25       &   1.6   &  12.9  &  6.5    \\
    &        &          &   50       &   3.2   &  14.4  &  6.5    \\ 
    &        &          &   75       &   4.8   &  15.1  &  7.8    \\ 
    HD 217107
    &  $J$     &     5    &   37       &   1.0   &  12.3  &         \\
    &        &          &   50       &   1.4   &  13.8  &  2.4    \\
    &        &          &   65       &   1.8   &  15.2  &         \\
    &        &          &   75       &   2.1   &  15.2  &  3.0    \\
    &        &          &   93       &   2.5   &  16.7  &         \\
    &        &          &   100      &   2.7   &  16.7  &  3.4    \\
    &        &          &   120      &   3.3   &  16.7  &         \\
    &        &          &   148      &   4.0   &  17.5  &         \\
    &        &          &   176      &   4.8   &  17.5  &         \\
    HD 319139
    &  $H$     &     5    & *~$^{(1)}$ &   5.0   &  18.0  &  2.9   \\
    &        &          & *~$^{(1)}$ &  10.0   &  17.3  &  2.7   \\
    HR 4796 $^{(2)}$
    &  $H$     &     5    &   100      &   1.5   &  12.6  &  1.0    \\
    &        &          &   500      &   7.5   &  17.3  &  2.4    \\
    & $K_{\rm s}$  
             &     1    &   100      &   1.5   &  11.5  &  1.4    \\
    &        &          &   500      &   7.5   &  16.5  &  2.0    \\
    HT Lup
    &  $H$     &     5    &   500      &   3.1   &  16.4  &  2.6    \\
    &        &          &   1000     &   6.0   &  17.6  &  1.9    \\ 
    & $K_{\rm s}$ 
             &     5    &   500      &   3.1   &  15.3  &  2.6    \\
    &        &          &   1000     &   6.0   &  16.5  &  2.3    \\
    SAO~185668
    &  $H$     &    10    & *~$^{(1)}$ &   1.0   &  --     &  --      \\
    &        &          & *~$^{(1)}$ &   5.0   &  --     &  --      \\
    \hline
  \end{tabular}
\par
  \medskip
$^{(1)}$ {The distances of HD~319139 and SAO~185668 are unknown.}
\\
$^{(2)}$ {A faint object at 4.7\arcsec~distance to HR~4796 turned out to be a background star, which was also identified by Mouillet et~al.\ (\cite{Mouillet}).}
\end{table}