\begin{table}%t1 \caption{O--C derived from photometry and spectroscopy of \hvezda. $s$ denotes standard deviation in mmags.} \label{OCtab} %\centering \par \small \begin{tabular}{rrlrcl} \hline \hline %\rule{0pt}{1.07em} Year~& O--C [d] \hspace{3pt} &$~s$&$N~$&Data&Source\\ \hline 1972 & 0.0580(70) & 4.4 & 48 & $\it{UVB}$ & \citet{winzer}\\ 1991 & $-0.0010(60)$ & 11 & 409 & $B_{{\rm T}}V_{{\rm T}}H\!p$ & \citet{esa97}\\ 1994 & $-0.0005(20)$ & $3.8$ & 317 &$uvby$ & \citet{adela}\\ 1995 & 0.0005(18) & $3.3$ & 299 &$uvby$ & \citet{adela}\\ 2006 & 0.0341(24) & & 564 &$EW$ & Lehmann et~al.\\ 2008 & 0.0000(17) & $4.8$ & 940 &$\mathit{BV}$ & this paper\\ \hline \end{tabular} \label{table} \end{table}