\begin{table}%t1 \caption{\label{tab:visir_observations}Summary of the VLT/VISIR observations.} \par %%\centering \par \begin{tabular}{lcccc} \hline \hline \noalign{\smallskip} Target & Observing epoch & Airmass & $T_{\rm int}$ & $F_{\nu}$(12.8~\mum) \\ & (Universal time) & & [s] & N/S [Jy] \\ \hline T Tau & 2008 Feb. 04 \ \ 02:09 & 1.73 & 143.5 & 7.8/12.1\\ HD 41047 & 2008 Feb. 04 \ \ 02:42 & 1.04 & 54.3 & 5.60 \\ T Tau & 2008 Feb. 08 \ \ 00:40 & 1.45 & 137.8 & 8.5/16.7\\ HD 75691 & 2008 Feb. 08 \ \ 01:17 & 1.33 & 52.0 & 9.72 \\ \hline \end{tabular} \tablefoot {All images were taken through the [NeII]~filter. The last column lists the source brightness at 12.8~\mum. For~the T~Tau observations, fluxes for the north and south components are individually given. The adopted fluxes of the calibrators HD~41047 and HD~75691 are taken from \cite{1999AJ....117.1864C}. The absolute flux calibration is good to~$\approx$10\%.} \vspace*{5mm} \end{table}