\begin{table}%t1
    \caption{\label{tab:obslog}Log of the ROSAT and XMM-Newton observations and of the optical
    photometry of AI~Tri.}
    %\centering
\par
    \begin{tabular}{clccrrcl}
      \hline\hline 
      \noalign{\smallskip}      
      Date & Telescope\tablefootmark{a} & Instrument & Filter &
      $t_{\rm exp} [{\rm s}]$ & $t_{\rm cycle} [{\rm s}]$ &
      Duration [h] & Observer\\[-3.2mm] \\ 
      \hline                    
      1998 Jan. 15$-$Feb. 05 & ROSAT & HRI & 0.1$-$2.4~keV & & & 9.6
         & PI Schwarz\\
      2005 Aug. 15 & XMM-Newton & EPIC/pn & 0.1$-$10~keV & & & 0.3
         & PI Reinsch\\
      2005 Aug. 15 & XMM-Newton & EPIC/MOS & 0.1$-$10~keV & & & 1.4
         & PI Reinsch\\
      2005 Aug. 15 & XMM-Newton & OM & UVM2 & & & 1.1 & PI Reinsch\\
      2005 Aug. 15 & XMM-Newton & RGS & 0.3$-$2.5~keV  & & & 1.3 & PI Reinsch\\
      2005 Aug. 22 & XMM-Newton & EPIC & 0.1$-$10~keV & & & 5.6 & PI Reinsch\\
      2005 Aug. 22 & XMM-Newton & OM & UVM2 & & & 5.6 & PI Reinsch\\
      2005 Aug. 17 & AIP 70~cm & TK1024-01 & V & 60 & 66 & 6.5 & Schwarz\\
      2005 Aug. 29 & AIP 70~cm & TK1024-01 & V & 60 & 66 & 7.6 & Schwarz\\
      2006 Nov. 09 & IAG 50~cm & STL-6303E & WL & 180 & 191 & 6.6 & Traulsen\\
      2006 Nov. 15 & IAG 50~cm & STL-6303E & V & 240 & 251 & 4.7 & Traulsen\\
      2006 Nov. 16 & IAG 50~cm & STL-6303E & V & 240 & 247 & 1.8 & Traulsen\\
      2007 Jan. 14 & IAG 50~cm & STL-6303E & V &  90$-$180 &  97$-$187 & 2.2
         & Traulsen\\
      2007 Jan. 25 & AIP 70~cm & TK1024-01 & V &  90 & 95 & 4.6 & Schwarz\\
      2007 Jan. 29 & M{\sc onet}/North & Alta E47+ & V &  15 &  18 & 1.8 &
           Hessman\\
      2007 Jan. 30 & M{\sc onet}/North & Alta E47+ & V &  15 &  18 & 2.0 &
           Hessman\\
      2007 Mar. 14 & IAG 50~cm & STL-6303E & V & 150 & 157 & 1.8 & Traulsen\\
      2007 Mar. 14 & AIT 80~cm & STL-1001E & V &  20$-$30 &  23$-$33 & 1.5
         & Nagel\\
      \hline                  
    \end{tabular}
    \tablefoot{\tablefoottext{a}{AIP: Astrophysikalisches Institut Potsdam. IAG:
      Institut f\"ur Astrophysik G\"ottingen. AIT: Institut f\"ur Astronomie
      und Astrophysik T\"ubingen, Abt.~Astronomie (Kepler Center for Astro and
      Particle Physics).}}
  \end{table}