\begin{table}%t2
\caption{\label{tab:obs}The parameters of the individual ISOPHOT PHT-P observations.}\vspace*{-2mm}
%\centerline
{\small
\begin{tabular}{lccccccccc}
\hline\hline\noalign{\smallskip}
%%Detector  &  Filter & PHT reference wavelength $\lambda_{ref}$ & Central wavelength $\lambda_c$ & Bandwidth ({\it FWHM}) $\Delta\lambda$ & 
%%Target Dedicated Time & Number of pointings & Absolute & Filter-to-filter & Mean error (PIA)\\
Detector  &  Filter & $\lambda_{\rm ref}$ & $\lambda_{\rm c}$ & $\Delta\lambda$ &  TDT & Number of & Absolute & Filter-to-filter & Mean error \\
 & & & & & number & pointings & accuracy & accuracy &  (in PIA) \\
 & & ($\mu$m) & ($\mu$m) & ($\mu$m) & & & (\%) & (\%) & (M~Jy~sr$^{-1}$)\\
\noalign{\smallskip}
\hline\noalign{\smallskip}
P1 & P7.3  & 7.3  & 7.41  & 3.38 & 43100201 & $2\times13$ & 40 & $<$20 & 6.18 \\
P1 & P7.7  & 7.7  & 7.66  & 0.82 & 43100211 & $2\times13$ & 40 & $<$20 & 3.59 \\
P1 & P10   & 10.0 & 10.00 & 1.80 & 43100202 & $2\times13$ & 40 & $<$20 & 4.73 \\
P1 & P11.3 & 11.3 & 11.36 & 0.81 & 43100203 & $2\times13$ & 40 & $<$20 & 9.00 \\
P1 & P11.5 & 12.0 & 11.88 & 6.53 & 43100204 & $2\times13$ & 40 & $<$20& 0.46 \\
P2 & P20   & 20.0 & 21.03 & 9.03 & 43100205 & $2\times13$ & $<$15 & 5 & 0.54 \\
\noalign{\smallskip}
\hline
\end{tabular}}%\vspace*{-2mm}
\tablefoot{$\lambda_{\rm ref}$, $\lambda_{\rm c}$, and $\Delta\lambda$ are the
reference wavelength, the central wavelength, the width of the PHT filter, respectively.}%\vspace*{-2mm}
\end{table}