\begin{table}%T1 \caption{\label{log}Log of observations.} \small%\centerline { \begin{tabular}{lllll} \hline \hline\noalign{\smallskip} Object & $\it{V}^{a}$ & Date & $N^{b}$ & Total IT$^{c}$\\ & (\rm mag) & & & (s) \\ \hline \multicolumn{5}{c}{T~Tauri}\\ %\hline RY Tau & 10.2 & 2004/Sep./05 & 8 & 2400 \\ & & 2005/Sep./03 & 4 & 2400 \\ PX Vul & 11.7 & 2005/Sep./03 & 8 & 4800 \\ %\hline \multicolumn{5}{c}{standards}\\ %\hline HD 147084$^{d}$ & 4.6 & 2004/Sep./05 & 8 & 1600 \\ HD 187929$^{d}$ & 3.9 & 2005/Sep./03 & 8 & 640 \\ HD 10476$^{e}$ & 5.2 & 2005/Sep./03 & 8 & 800 \\ \hline \end{tabular}} \smallskip $^a$ From Simbad; $^b$ number of waveplate positions; $^c$ total integration time ($N\ \times$ individual IT by waveplate position); $^d$ polarized; $^e$ unpolarized. \end{table}