\begin{table}%t1 \caption{\label{xlog}Log of the XMM X-ray observations of HU Aqr.} %\centerline {\begin{tabular}{llcc} \noalign{\smallskip} \hline\hline \noalign{\smallskip} Date & Detector$^{1}$ & $T_{\rm Exp}$ & Mean rate$^{2}$ \\ & & (ks) & (cts/s) \\ \noalign{\smallskip} \hline \noalign{\smallskip} 2002 May 16--17 & PN-sw & 36.4& 1.11 \\ & MOS1-sw & 37.2 & 0.19 \\ & MOS2-sw & 37.2 & 0.26 \\ 2003 May 19 & PN-ti & 18.5 & 0.94 \\ & MOS1-ti & 20.2 & 0.21 \\ & MOS2-ti & 20.0 & 0.18 \\ 2003 Oct. 24--25 & PN-sw & 11.4 & 0.011 \\ & MOS1-sw & 11.6 & --\\ & MOS2-sw & 11.6 & --\\ 2005 May 16 & PN-ti & 18.6 & --\\ & MOS1-sw & 19.4 & 0.0025 \\ & MOS2-sw & 19.4 & 0.0022\\ \noalign{\smallskip} \hline \noalign{\smallskip} \end{tabular}} \par \smallskip \noindent {\Ni\small $^{1}$ The abbreviations after the PN/MOS detector indicate the instrument mode: sw~=~small window, ti~=~timing. $^{2}$ In the bright phase interval $\phi = 0.62{-}0.91$ and $\phi = 0.05{-}0.18$. Energy range used 0.18--10~keV and 0.3--10~keV for imaging and timing modes, respectively. Count rates have been corrected for the~65\% encircled energy fraction corresponding to the aperture used. } \end{table}