\begin{table}%t2 \caption{\label{table:opt1}LFI optical performance.} %\centering \par \begin{tabular}{l c c c c c c c} \hline\hline\noalign{\smallskip} & ET & {\it FWHM} & $e$ & XPD & Ssp & Msp \\ \hline 70 &$17$~dB at $22^\circ$ &13.03&1.22&$-$34.73&0.17 & 0.65 \\ 44 &$30$~dB at $22^\circ$ &26.81&1.26&$-$30.54&0.074& 0.18 \\ 30 &$30$~dB at $22^\circ$&33.34&1.38&$-$32.37&0.24 & 0.59 \\ \hline \end{tabular} \tablefoot {All the values are averaged over all channels at the same frequency. ET~is the horn edge taper measured at~$22^{\circ}$ from the horn axis; {\it FWHM} is the angular resolution in arcmin; $e$~is the ellipticity; XPD is the cross-polar discrimination in~dB; Ssp~is the Sub-reflector spillover~(\%); Msp~is the Main-reflector spillover~(\%). See~text for~\mbox{details}.} \vspace{2.5mm}\end{table}