\begin{table}%t1
\caption{\label{tab:all_observations}Observational material for the construction of the light curve.}
%\centering
\par
\begin{tabular}{lrrlc}
\hline\hline\noalign{\smallskip}
Telescope         &  $N_{\rm t}$    & $N_{\rm e}$   & Years          & Source\\ 
\hline\noalign{\smallskip}
\multicolumn{5}{l}{(a) Digitized photographic plates:} \\
Asiago Schmidt     &   24           &  8            & 1968.8--1993.1 & (1)\\
Calar Alto Schmidt &   43           & 15            & 1983.0--2000.7 & (1)\\
Calar Alto 1.2~m  &    8           &  5            & 1976.7--1982.6 & (1)\\
Palomar Schmidt    &    4           &  4            & 1948.7--1989.7 & (1), (3)\\		   
Sonneberg 40~cm   &    9           &  1            & 1992.2--1992.6 & (1)\\
Tautenburg Schmidt &  362           & 77            & 1961.5--1997.0 & (1)\\
&&&&\\
\multicolumn{5}{l}{(b) CCD observations:} \\
Calar Alto 2.2~m  &    3           &  2            & 2008.7--2009.3 & (1)\\
CFHT 3.6~m        &    1           &  1            & 1993.8         & (1)\\
INT (WFS)          &    5           &  1            & 1998.8         & (1)\\
INT 		            &  522           &  6            & 1999.7--2003.7 & (2)\\
Kitt Peak 4~m     &   10           &  2            & 2000.8,2001.7  & (4)\\ 		    		
Skinakas 60~cm    &    5           &  1            & 2007.6         & (1)\\
Tautenburg Schmidt &   30           & 14            & 2006.1--2009.7 & (1)\\
&&&&\\
\multicolumn{5}{l}{(c) Original data from Sharov et~al. (\cite{Sharov98}):} \\
four other telescopes & $\sim $150     & 84            & 1969.0--1997.7 & (5)\\  		\hline
\end{tabular}
\end{table}