\begin{table}%t1
\caption{The exposure time and the observation details for the {\it Chandra} and HST~observations of NGC~5548. ACIS stands for the Advanced CCD~Imaging Spectrometer and HRC for High Resolution Camera. The E140M grating covers the wavelength range between $1150{-}1730$~\AA, the E230M~grating between $1607{-}3119$~\AA.}\label{tab:obs}
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\par
\begin{tabular}{llll}
\hline \hline
Instrument & Detector & Start date  & Exposure (ks)\\
\hline
HETGS     & ACIS-S &2002 Jan. 16& 154 \\
LETGS     & HRC-S  &2002 Jan. 18& 170 \\
LETGS     & HRC-S  &2002 Jan. 21& 170 \\
\hline
HST STIS  & E140M  &2002 Jan. 22& 7.6 \\
HST STIS  & E230M  &2002 Jan. 22& 2.7 \\
HST STIS  & E140M  &2002 Jan. 23& 7.6 \\
HST STIS  & E230M  &2002 Jan. 23& 2.7 \\
\hline
\end{tabular}
\end{table}