\begin{table}%t1
\caption{\label{comchem_dataset}Subset of the data from \citet{Rauer2002} used for analysis with the ComChem model. The first column gives the date of the observation, $r_{\rm h}$ (negative for pre-perihelion) and $\Delta$ are the heliocentric and geocentric distance of the comet, the fourth column gives the telescope and instrument used, the fifth column denotes how many spectra have been averaged in the observing run, the sixth column shows the resulting total integration time, $\Delta\rho$ is the spatial resolution of the profiles and the last column lists comments on the observations.}
%\centering
\par
\begin{tabular}{l|ccccccl}
 \hline\hline
Date    &$r_{\rm h}$  &  $\Delta$ & Telescope/ &Number of spectra    & Total int. time   & $\Delta\rho$ & Comment \\
    & [AU]  &  [AU]     & Instr.&  averaged     & [s]         & 10$^3$[km]  &\\
\hline
17.8.1996  & --3.39   &  2.8  & Danish 1.5/DFOSC     & 2     & 1800      & 7.86 & \chem{C_3} contaminated \\
2.10.1996  & --2.86   &  3.0  & Danish 1.5/DFOSC   & 2     & 1800      & 8.09 &  \\[.5ex]
23.11.1997 & 3.51    &  3.4  & ESO 1.5/B\&C    & 4     & 4800      & 18.8 & not photometric \\
6.12.1997  & 3.66    &  3.5  & Danish 1.5/DFOSC    & 6     & 5400     & 10.3 &  \chem{C_3} contaminated \\
19.12.1997 & 3.78    &  3.6  & ESO 1.5/B\&C    & 3     & 3600      & 21.6 &  \\
20.1.1998  & 4.13    &  4.0  & ESO 1.5/B\&C    & 4     & 3900      & 23.7 &  \\
21.1.1998  & 4.14   &  4.0   & Danish 1.5/DFOSC   & 4     & 3900      & 11.7 & \chem{C_3} contaminated \\
21.3.1998  & 4.74   &  4.8   & ESO 1.5/B\&C   & 3     & 2700      & 25.6 &  \\
\hline
\end{tabular}
\end{table}