\begin{table}%t1 \caption{\label{tbl:obstime}Observation runs at the Nordic Optical Telescope contributing to this survey.} \small%\centering \par \begin{tabular}{llcrl} \hline\hline\noalign{\smallskip} ID & Dates & $N_n$ & $N_t$ & Observers \\ \hline N1 & 1999 July 19--23 & 4.0 & 13 & JES, RS, JMGP \\ N2 & 1999 Oct.~14--19 & 5.0 & 31 & JES, RH\O \\ N3 & 2000 July 7--11 & 4.0 & 25 & RH\O, RS \\ N4 & 2000 Oct.~4--8 & 4.0 & 38 & JES, RH\O \\ N5 & 2001 July 25--29 & 4.0 & 22 & RH\O, RS \\ N6 & 2002 Oct.~10--15 & 0.5 & 4 & JES\tablefootmark{a} \\ N7 & 2004 June 4 -- 8 & 4.0 & 44 & JES, RH\O \\ No & 2005 Feb.~15--20 & 5.0 & 0 & JES\tablefootmark{b} \\ N8 & 2006 Dec.~10--15 & 0.3 & 4 & JES\tablefootmark{a} \\ N9 & 2007 Dec.~14--16 & 3.0 & 14 & RH\O, JHT\tablefootmark{c} \\ X1 & 2004 Oct.~15--17 & 0.3 & 4 & JES, RH\O\tablefootmark{d} \\ S1 & 2004 May 21--24 & 4.0 & 20 & RO \\ S2 & 2005 May 30--June 1 & 4.0 & 15 & RO \\ S3 & 2007 Oct.~20--24 & 3.0 & 11 & RO \\ S4 & 2008 Sep.~22-25 & 3.0 & 20 & RO \\ S5 & 2008 July 26--30 & 2.0 & 67 & RH\O\tablefootmark{e} \\ S6 & 2009 Jan.~24--27 & 3.0 & 5 & RO \\ T1 & 2001 Feb.~24 & 0.6 & 7 & RH\O\tablefootmark{f} \\ T2 & 2001 April 10, 13 & 2.0 & 24 & RH\O\tablefootmark{e} \\ T3 & 2002 Sep.~13--14& 0.2 & 4 & RH\O, JHT\tablefootmark{f} \\ T4 & 2003 Feb.~10--19& 0.5 & 5 & RH\O, JHT\tablefootmark{f} \\ T5 & 2004 Jan.~13 & 0.5 & 9 & RH\O, JHT\tablefootmark{f} \\ T6 & 2005 May 5 & 0.7 & 16 & RH\O\tablefootmark{f} \\ T7 & 2006 May 9 & 0.7 & 15 & RH\O\tablefootmark{f} \\ T8 & 2008 Feb. 24, 26 & 0.2 & 2 & RH\O\tablefootmark{f} \\ ST & 2006 June 10 & 0.5 & 2 & JMGP\tablefootmark{g} \\ \multicolumn{2}{l}{Total} & 59.0 & 421 & \\ \hline \end{tabular} \tablefoot{The ID column gives our run identifier, used to refer to a particular observation run in Table~\ref{tbl:limits} and when discussing particular observations. $N_{\rm n}$ gives the number of nights used for this survey programme. For nights allocated to the survey, the number includes all nights, regardless of whether any observations were actually made or not. For nights where this programme served as a backup for another, only the fraction of nights actually used for this programme is listed. The $N_{\rm t}$ column shows the number of targets observed. Note that reobservations and observations of sdO stars (to be analysed in a separate paper) are included in these totals. The notes indicate.\\ \tablefoottext{a}{Run primarily dedicated to an unrelated target.}\\ \tablefoottext{b}{Run lost due to snow and ice.}\\ \tablefoottext{c}{Run primarily for follow-up of our pulsators.}\\ \tablefoottext{d}{{\sc Xcov}~24 multi-site campaign.}\\ \tablefoottext{e}{Run primarily dedicated to search for sdO stars.}\\ \tablefoottext{f}{Run primarily for technical investigations.}\\ \tablefoottext{g}{Spanish service time.}} \end{table}