\begin{table}%t3 \caption{\label{polstd}Polarisation degrees and observing dates of standard stars: highly-polarised and (in italics) non-polarised. } %\centerline {\begin{tabular}{{lclcccccc}} \hline\hline\noalign{\smallskip} {Object} & Date & {Filter} & $Q/I^1$ & $U/I^1$ & $P_{\rm Obs}$ & $P_{\rm Foss}$ & $\theta_{\rm Obs} $ & $\theta_{\rm Foss}$ \\ &(UT) & & (\%) & (\%) & (\%) & (\%) & ($^{\rm o}$) & ($^{\rm o}$) \\ \hline {\it WD1615-154} & 02/08/05 & $R$-Bessel & $+0.13$ & $+0.16$ & $0.14$ & ... & $-25$ & ...\\ {\it WD1344+106} & 01/08/05 & $I$-Bessel & $-0.07\pm0.13$ & $+0.13\pm0.11$ & 0--0.199 & ... & $+34\pm23$ & ...\\ \hline {\it WD0310-688} & 19/08/06 & $I$-Bessel & $+0.17$ & $+0.03$ & $0.17$ & ... & +5 & ... \\ {\it WD0310-688} & 21/08/06 & $I$-Bessel & $+0.05$ & $+0.06$ & $0.08$ & ... & +24 & ... \\ \hline Hiltner 652 & 03/08/05 & V-Bessel & $+6.29$ & $+0.33$ & 6.30 & $6.25\pm 0.01$ & 179.7 & $179.18\pm0.20$\\ Hiltner 652 & 03/08/05 & $R$-Bessel & $+5.90$ & $-0.28$ & 5.91 & $6.07\pm0.02$ & 179.8& $179.39\pm0.10$\\ NGC 2024 &03/08/05 & $R$-Bessel & $-0.22$ & $-9.63$ & 9.63 & $9.62\pm 0.01$ & 45.5 & $135.84\pm0.02$\\ NGC 2024 &03/08/05 & $I$-Bessel & $-0.48$ & $-9.13$ & 9.14 & $9.12\pm 0.04$ & 46.4 & $136.26\pm0.15$\\ NGC 2024 & 03/08/05 & V-Bessel & $+0.57$ &$-9.58$ & $9.60$ & $9.65\pm 0.06$ & 134.9 & $135.47\pm0.59$\\ \hline Hiltner 652 & 01/08/06 & $I$-Bessel & $+5.43$ & $-0.64$& $5.47$ & $5.61\pm0.04 ^3$& 179.5 & $179.18\pm0.11^3$\\ Hiltner 652 & 02/09/06 & $I$-Bessel & $+5.55$ & $-0.59$ & $5.52$ & $5.61\pm0.04^3$& 179.8 & $179.18\pm0.11^3$\\ NGC 2024 &03/09/06 & $R$-Bessel & $-0.11$ & $-9.58$ & 9.58 & $9.62\pm 0.01$ & 45.9 & $135.84\pm0.02$\\ NGC2024 & 10/08/06 & $I$-Bessel & $-0.59$ & $-9.16$ & 9.18 & $9.12\pm 0.04$ & 46.0 & $136.26\pm0.15$\\ BD-125133 & 02/09/06 & $I$-Bessel & $+1.04$ & $-3.38$ & 3.54 & $3.57\pm0.09$ & 146.4 & $143.99\pm2.27$\\ \hline \end{tabular}} \medskip \par $^1$ The $Q/I$ and $U/I$ values are {\it not} corrected for the pleochroism (see text). % \item[$^2$] $^2$ The reference polarisation degrees {and angles} are from \citet{Fossa07}. % \item[$^3$] $^3$ \citet{Fossa07} only reports measurements using the PMOS mode. For the $B$ and $V$ filters for which they report measurements in both IPOL and PMOS modes, one finds differences up to $(0.10\pm0.02)$\% and $(0.38\pm0.14)\deg$. % \end{list} \end{table}