\begin{table}%t2 \caption{\label{table2}Photometric measurements.} %\centerline {\small \begin{tabular}{ccccrrrc} \hline\hline Band & $\lambda_{\rm{central}}$ & Date & Instrument & \multicolumn{1}{c}{T~Tau N} & \multicolumn{1}{c}{T~Tau Sa} & \multicolumn{1}{c}{T~Tau Sb} & Reference\\ & [$\mu$m] & & & & & & \\ \hline $U$ & 0.36 & 21--10--2004 & Phot. / Mt. Maidanak& $11.74\pm0.04$~mag &-- &-- & $^a$\\ $B$ & 0.43 & Oct. 2004 & KING / MPIA & $11.2\pm0.1$~mag &-- &-- & $^b$\\ $V$ & 0.55 & Oct. 2004 & KING / MPIA &$9.9\pm0.1$~mag &-- &--&$^b$\\ $R$ &0.70 & Oct. 2004 & KING / MPIA & $ 8.9\pm0.1$~mag &--&-- & $^b$\\ $I$ & 0.90 & Oct. 2004 & KING / MPIA &$ 8.3\pm0.1$~mag &--&-- & $^b$\\ $J$ & 1.25 & 14--12--2002 & NACO / VLT& $7.1\pm0.1$~mag & $>$14.5~mag & $12.9\pm0.1$~mag & $^c$\\ $H$ & 1.65 & 14--12--2002 & NACO / VLT& $6.2\pm0.1$~mag &$12.3\pm0.1$~mag & $10.4\pm0.1$~mag & $^c$\\ $K$s & 2.16 & 14--12--2002 & NACO / VLT & $5.7\pm0.1$~mag& $9.2\pm0.1$~mag & $ 8.8\pm0.1$~mag & $^c$\\ $L$' & 3.80 & 13--12--2002 & NIRC-2 / Keck& $4.32\pm0.05$~mag & $5.64\pm0.03$~mag & $ 6.25\pm0.03$~mag & $^{d,e}$\\ $M$s & 4.67 & 13--12--2002 & NIRC-2 / Keck& $4.13\pm0.10$~mag & $ 4.96\pm0.06$~mag & $ 5.77\pm0.06$~mag & $^{d,f}$\\ & 8.5 & Oct./Nov. 2004 & MIDI/VLTI & $5.6\pm0.2$~Jy & $2.6\pm0.2$~Jy & $1.0\pm0.1$~Jy & $^b$\\ & 9.0 & Oct./Nov. 2004 & MIDI/VLT& $6.7\pm0.3$~Jy & $1.5\pm0.2$~Jy & $0.6\pm0.1$~Jy & $^b$\\ & 9.5 & Oct./Nov. 2004 & MIDI/VLTI & $7.4\pm0.5$~Jy & $1.0\pm0.2$~Jy & $0.4\pm0.1$~Jy & $^b$\\ & 10.0 & Oct./Nov. 2004 & MIDI/VLTI & $8.4\pm0.4$~Jy & $1.1\pm0.2$~Jy & $0.5\pm0.1$~Jy & $^b$\\ & 10.5 & Oct./Nov. 2004 & MIDI/VLTI & $8.8\pm0.4$~Jy & $1.6\pm0.3$~Jy & $0.7\pm0.2$~Jy & $^b$\\ & 11.0 & Oct./Nov. 2004 & MIDI/VLTI & $8.8\pm0.4$~Jy & $2.3\pm0.3$~Jy & $0.9\pm0.2$~Jy & $^b$\\ & 11.5 & Oct./Nov. 2004 & MIDI/VLTI & $8.7\pm0.4$~Jy & $3.2\pm0.4$~Jy & $1.1\pm0.2$~Jy & $^b$\\ & 12.0 & Oct./Nov. 2004 & MIDI/VLTI & $8.4\pm0.5$~Jy & $4.4\pm0.5$~Jy & $1.3\pm0.2$~Jy & $^b$\\ & 12.5 & Oct./Nov. 2004 & MIDI/VLTI & $7.8\pm0.5$~Jy & $5.3\pm0.6$~Jy & $1.3\pm0.3$~Jy & $^b$\\ %\hline $Q$ & 19.91 & 27--08--1996 & MAX / UKIRT & \multicolumn{1}{r}{$20\pm 5$~Jy} &\multicolumn{2}{r}{------------------ \ \ $28\pm7$~Jy\ \ -----------} & $^g$\\ &25 & 25--09--1997 & ISOPHOT &\multicolumn{3}{r}{-----------------------$\ \ \ \ 40.88\pm \ \ 6.13$~Jy\ \ ---------------------} & $^b$\\ & 60 & 25--09--1997 & ISOPHOT & \multicolumn{3}{r}{-----------------------$\ \ 117.77\pm 17.67$~Jy\ \ ---------------------} & $^b$\\ & 100 & 25--09--1997 & ISOPHOT & \multicolumn{3}{r}{-----------------------$\ \ 105.55\pm 15.83$~Jy\ \ ---------------------} & $^b$\\ & 150 & 25--09--1997 & ISOPHOT & \multicolumn{3}{r}{-----------------------$\ \ 113.39\pm 17.01$~Jy\ \ ---------------------} & $^b$\\ & 170 & 25--09--1997 & ISOPHOT & \multicolumn{3}{r}{-----------------------$\ \ \ \ 82.79\pm 12.42$~Jy\ \ ---------------------} & $^b$\\ & 350 & 2004--2005 & CSO & \multicolumn{3}{r}{-----------------------$\ \ \ \ 8.149\pm0.253$~Jy ----------------------} & $^h$\\ & 450 & 1997--2002 & SCUBA / JCMT & \multicolumn{3}{r}{-----------------------$\ \ \ \ 1.655\pm0.218$~Jy ----------------------} & $^h$\\ & 840 & 28--10--1994 & JCMT \& CSO & \multicolumn{3}{r}{-----------------------$\ \ \ \ 1.350\pm0.675$~Jy ----------------------} & $^i$\\ & 850 & 1997--2002 & SCUBA / JCMT & \multicolumn{3}{r}{-----------------------$\ \ \ \ 0.628\pm0.017$~Jy ----------------------} & $^h$\\ & 1100 & 01--12--1994 & OVRO & $0.397\pm0.035$~Jy & \multicolumn{2}{r}{----------------- \ \ $<$0.100~Jy\ \ ----------} & $^i$\\ & 1300 & April 1988 & IRAM & \multicolumn{3}{r}{-----------------------$\ \ \ \ 0.280\pm0.009$~Jy ----------------------} & $^h$\\ & 2800 & 1996--1997 & BIMA & $0.050\pm0.006$~Jy & \multicolumn{2}{r}{----------------- \ \ $<$0.009~Jy----------} & $^j$\\ \hline \end{tabular}} \medskip $^a$ Melnikov, S. (private communication); $^b$ this work; $^c$~\cite{herbst07}; $^d$~\cite{duchene05}: flux ratios; $^e$~\cite{beck04}: flux of T~Tau~N; $^f$~\cite{ghez91}: flux of T~Tau~N; $^g$~\cite{herbst97}; $^h$~\cite{andrews05} and references therein; $^i$~\cite{hogerheijde97}; $^j$ \cite{akeson98}. \end{table}