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\begin{document}

\IBVShead{5341}{26 November 2002}

\IBVStitletl{New Photoelectric and CCD Minima and Updated}{ Ephemerides of Selected Eclipsing Binaries}

\IBVSauth{Pribulla, T.$^1$; Va\v{n}ko, M.$^1$; Parimucha, \v{S}.$^2$; Chochol, D.$^1$}

\IBVSinst{Astronomical Institute of the Slovak Academy of Sciences, 059 60 Tatransk\'a Lomnica, Slovak Republic; \\ e-mail: (pribulla,vanko,chochol)@ta3.sk}

\IBVSinst{Faculty of Science, Department of the Theoretical Physics and
Geophysics, University of  P.J. \v{S}af\'arik,\\ 040 01 Ko\v{s}ice,
Slovak Republic; e-mail: parimuch@ta3.sk}

\IBVSabs{This report presents minima times and updated}
\IBVSabs{ephemerides of selected eclipsing binaries}

\IBVStyp{ Eclipsing binary }


\begintext

We present 90 new minima times of 35 eclipsing binaries obtained from
March 2001 to November 2002 as a part of the program of their full light curve
coverages. The $UBVR$ photoelectric observations were taken 
at the Skalnat\'e Pleso (SP) and Star\'a Lesn\'a (SL) observatories of the 
Astronomical Institute of the Slovak Academy of Sciences. In both cases the 
0.6-m Cassegrain telescope equipped with a single-channel pulse-counting 
photoelectric photometer was used. For all observations a 10 second integration
was used. Data reduction, the atmospheric extinction correction and 
transformation to the standard {\it UBV} system were carried 
out in the usual way. $VRI$ CCD observations were obtained at the Roztoky Observatory
($\lambda$ = 21\deg28\arcm54\arcs E, $\varphi$ = 49\deg33\arcm57\arcs N).
The 40cm Cassegrain telescope equipped with the SBIG ST-8 CCD camera and
standard $VRI$ filters was used. The exposure times for the $V$ and $RI$
passbands were 20 s and 10 s, respectively. The frames were reduced using 
standard procedure (bias and dark subtraction, flat field correction) and the
brightness of the variable was determined by aperture photometry with respect
to usually two close standard stars using the MuniPack package 
({\tt http://www.ian.cz/munipack/}). Since the field of view of the camera
is 7\farcm9$\times$11\farcm9 no extinction correction to the differential
 magnitudes has been applied.


\begin{table}
\caption{New times of primary (I) and secondary (II) minima.
The standard errors are given in parentheses}
\begin{center}
\normalsize
\tabcolsep 3pt
\begin{tabular}{llccc|llccc}
\hline
System & JD$_{hel}$ & Min. & Obs. & Fil. &
System & JD$_{hel}$ & Min. & Obs. & Fil. \\
       & 2400000+   &      &      &      &
       & 2400000+   &      &      &      \\
\hline
RT And   & 52251.2951(1): & I  & SP & RVR    &  SS Com   & 52403.5158(4)  &  I & RO & VRI \\
         & 52481.4838(1)  & I  & SL & BV     &           & 52404.3402(4)  &  I & RO & VI  \\
AB And   & 52258.2736(2)  & II & SL & BV     &           & 52404.5485(2)  &  I & RO & VI  \\
         & 52484.4591(1)  & I  & SL & BV     &  YY CrB   & 52352.5466(2)  &  I & SL & UBV \\
BX And   & 52231.2850(1)  & I  & SL & BV     &  CG Cyg   & 52490.4190(1)  &  I & SL & BV  \\
EP And   & 52200.3698(1): & II & SL & BV     &  V1191 Cyg& 52413.4450(4)  &  I & RO & VRI \\
SS Ari   & 52528.5036(2)  & II & SL & BV     &           & 52445.4067(2)  &  I & RO & VRI \\
V402 Aur & 52224.467(2)   & II & SL & UBV    &           & 52456.3748(1)  &  I & RO & RI  \\
44i Boo  & 52363.5934(5): & I  & SP & BVR    &           & 52465.4622(4)  &  I & SL & BV  \\
         & 52364.5293(1)  & II & SL & BV     &           & 52528.3033(4)  &  II& SL & BV  \\
DU Boo   & 52380.2145(3)  & II & SL & BV     &           & 52548.3544(3)  &  II& SL & BV  \\
         & 52380.7202(2)  &  I & SL & BV     &  EF Dra   & 52031.3346(2)  &  I & SL & V   \\
FI Boo   & 52043.4593(3)  & II & SL & BV     &           & 52139.4607(1)  &  I & SL & BV  \\
         & 52053.4095(2)  &  I & SL & B      &           & 52189.2824(2)  &  II& SL & BV  \\
SV Cam   & 52195.2740(1)  &  I & SL & BV     &           & 52203.2757(1)  &  II& SL & BV  \\
         & 52198.5365(2)  & II & SL & BV     &           & 52252.2516(8)  &  I & SP & BVR \\
         & 52200.3178(3)  & II & SP & BVR    &           & 52321.5799(1)  &  II& SL & BV  \\
         & 52200.6124(3)  &  I & SP & BVR    &           & 52348.5043(2)  &  I & RO & VRI \\
         & 52282.4535(4)  &  I & SP & BR     &           & 52352.3203(1)  &  I & RO & RI  \\
DN Cam   & 52247.5230(1)  &  II& SL & UBV    &           & 52352.5360(3)  &  II& RO & VR  \\
         & 52568.4322(3)  &  II& SL & UBV    &           & 52401.5073(3)  &  I & SL & BV  \\
FN Cam   & 52445.3947(3)  &  I & SL & UBV    &           & 52550.3423(2)  &  I & SL & BV  \\
TX Cnc   & 52348.4185(3)  &  I & SL & BV     &  FU Dra   & 52464.4278(3)  &  II& SL & BV  \\
         & 52352.4397(2)  &  II& SL & BV     &  SW Lac   & 52156.3371(2)  &  I & SL & UBV \\
WY Cnc   & 52339.4598(6)  &  II& SL & V      &           & 52191.4550(1)  &  II& SL & UV  \\
         & 52342.3736(1)  &  I & SL & UBV    &           & 52505.4351(2)  &  II& SL & BV  \\
         & 52352.3260(1)  &  I & SP & BVR    &  AM Leo   & 52397.3557(1)  &  I & SL & BV  \\
CW Cas   & 52200.2777(1)  &  I & SL & BV     &  V714 Mon & 52309.3076(2)  &  I & SL & BV  \\
         & 52311.2418(1)  &  I & SL & BV     &           & 52311.3742(1)  &  I & SL & BV  \\
         & 52527.4299(2)  &  I & SL & BV     &  V432 Per & 52320.2634(2)  &  I & SL & UBV \\
V523 Cas & 52504.4610(2)  & II & SL & BV     &           & 52547.3745(3)  &  II& SL & UBV \\
         & 52504.5786(1)  &  I & SL & V      &           & 52547.5653(3)  &  I & SL & UBV \\
VW Cep   & 52139.3413(2)  &  I & SL & UBV    &           & 52585.3201(3)  &  II& SL & BV  \\
         & 52182.3447(4)  &  II& SL & UBV    &  XY UMa   & 52251.4842(4)  &  I & SP & BVR \\
         & 52202.2363(1)  &  I & SP & BVR    &           & 52278.5530(10) &  II& SL & BV  \\
         & 52202.3801(2)  &  II& SP & BVR    &           & 52311.3600(3)  &  I & SP & BVR \\
         & 52202.5157(3)  &  I & SP & BVR    &           & 52311.6028(8)  & II & SP & BVR \\
         & 52240.5074(6): &  II& SP & UBVR   &           & 52322.3777(1)  &  I & SL & BV  \\
         & 52452.4398(4)  &  I & SL & UBV    &           & 52322.6132(1)  & II & SL & VB  \\
         & 52453.4164(3)  & II & SL & UBV    &           & 52351.3539(8)  & II & RO & VRI \\
WZ Cep   & 52217.3841(3)  & II & SL & BV     &           & 52351.5951(2)  &  I & RO & VRI \\
EG Cep   & 52444.4255(1)  &  I & SL & BV     &  AA UMa   & 52367.5846(3)  &  II& RO & RI  \\
GW Cep   & 52185.2687(2)  &  I & SL & BV     &  AW UMa   & 52311.6006(6)  &  II& SL & UBV \\
         & 52185.4285(1)  & II & SL & BV     &  ER Vul   & 52492.4670(2)  &  I & SL & V   \\
EE Cet   & 52548.4392(3)  & II & SL & UBV    &           & 52512.3626(4)  & II & SL & BV  \\
\hline
\end{tabular}
\end{center}
\end{table}

\begin{table}
\caption{New ephemerides of the observed eclipsing close binaries.
The standard errors are given in parentheses, e.g., the entry 52137.5296(14)
should be interpreted as 52137.5296$\pm$0.0014.}
\begin{center}
\normalsize
\begin{tabular}{lllcl}
\hline
System   &   JD$_0$       & Period         & Interval    &  Period          \\
         & 2\,400\,000+   &                &             &  change          \\
\hline
RT And   & 52481.4848(3)  & 0.62892929(2)  & 1971 - 2002 & $\searrow$       \\
AB And   & 52484.4584(6)  & 0.33189189(12) & 1994 - 2002 & LT + $\nearrow$  \\
BX And   & 52231.2862(7)  & 0.61011291(10) & 1981 - 2002 & LT ?             \\
EP And   & 52137.5296(14) & 0.40411058(15) & 1982 - 2001 & $\rightarrow$    \\
SS Ari   & 52528.7093(13) & 0.40598385(19) & 1981 - 2002 & $\searrow$       \\
V402 Aur & 52224.7691(12) & 0.6034992(3)   & 1991 - 2001 &                  \\
44i Boo  & 52364.6634(7)  & 0.26781915(6)  & 1988 - 2002 & LT + $\nearrow$  \\
DU Boo   & 52380.720(2)   & 1.0558882(9)   & 1991 - 2002 &                  \\
FI Boo   & 51718.3979(14) & 0.3899978(4)   & 1991 - 2001 &                  \\
CW Cas   & 52527.4311(8)  & 0.3188621(2)   & 1994 - 2002 & $\searrow$       \\
V523 Cas & 52504.5730(7)  & 0.23369229(5)  & 1987 - 2002 & LT               \\
SV Cam   & 52282.4579(6)  & 0.59307301(9)  & 1979 - 2002 & LT ?             \\
DN Cam   & 52568.6830(6)  & 0.49830902(15) & 1991 - 2002 &                  \\ 
FN Cam   & 52445.3977(9)  & 0.6771318(5)   & 1991 - 2002 &                  \\
TX Cnc   & 52352.6287(13) & 0.38288247(9)  & 1977 - 2002 & $\nearrow$ ?     \\
WY Cnc   & 52352.3270(7)  & 0.82936867(14) & 1984 - 2002 & $\searrow$       \\
VW Cep   & 52506.4328(9)  & 0.27831149(17) & 1995 - 2002 & LT + $\searrow$  \\
WZ Cep   & 52217.5933(17) & 0.41744491(12) & 1982 - 2001 &                  \\
EG Cep   & 52444.4282(6)  & 0.54462272(6)  & 1974 - 2002 & $\nearrow$       \\
GW Cep   & 52185.5871(7)  & 0.31882957(12) & 1991 - 2001 & $\searrow$       \\
EE Cet   & 52548.6291(10) & 0.3799207(3)   & 1991 - 2002 &                  \\
SS Com   & 52403.5127(19) & 0.4128184(6)   & 1996 - 2002 & $\nearrow$       \\
YY CrB   & 52352.5464(6)  & 0.3765642(3)   & 1991 - 2002 & $\rightarrow$    \\
CG Cyg   & 52490.4173(5)  & 0.63114360(10) & 1990 - 2002 & LT ?             \\
V1191 Cyg& 52548.5110(16) & 0.3133818(8)   & 1997 - 2002 & $\nearrow$       \\
EF Dra   & 52550.3408(7)  & 0.42402593(9)  & 1989 - 2002 & LT + $\nearrow$ ?\\
FU Dra   & 52464.5785(5)  & 0.30671687(11) & 1991 - 2002 & $\rightarrow$    \\
SW Lac   & 52505.5960(8)  & 0.32071417(16) & 1994 - 2002 & LT + $\nearrow$  \\
AM Leo   & 52397.3557(13) & 0.36579762(12) & 1988 - 2002 & LT ?             \\
V714 Mon & 52311.3756(9)  & 0.34450930(15) & 1995 - 2002 & $\rightarrow$    \\
V432 Per & 52547.5658(7)  & 0.3833101(2)   & 1997 - 2002 & LT ?             \\
XY UMa   & 52351.5911(5)  & 0.47899511(4)  & 1931 - 2002 & LT + $\nearrow$  \\
AA UMa   & 52367.8160(14) & 0.46812712(15) & 1987 - 2002 & $\nearrow$       \\
AW UMa   & 52311.8218(12) & 0.4387261(2)   & 1995 - 2002 & $\searrow$       \\
ER Vul   & 52512.7111(11) & 0.69809518(13) & 1978 - 2002 & $\rightarrow$    \\
\hline
\multicolumn{5}{l}{LT - light-time effect, $\nearrow$ - period increase,
$\searrow$ - period decrease,}\\
\multicolumn{5}{l}{$\rightarrow$ - constant period}
\end{tabular}
\end{center}
\end{table}


\IBVSedata{5341-t1.txt}
\IBVSedata{5341-t2.txt}

We have calculated the times of minima separately for all filters 
using the Kwee and Van Woerden's method, parabola fit, sliding integration 
method, tracing paper and ``center of mass'' method which were described 
in detail by Ghedini (1982). The computer codes were kindly provided by 
Kom\v{z}\'{\i}k (2000). The average times of the minima from all used filters
are given in Table~1. Part of the new minima of 44i Boo can be found in 
Pribulla et al. (2001). For DU Boo we determined only one normal primary 
minimum from all observations obtained in spring 2002.

We have also collected all available minima times of these eclipsing binaries
from literature and from compilations provided by Kreiner (2001). 
The CCD, photoelectric and visual minima were weighted according to their
average precision. Since the period changes in close binaries are rather 
frequent and pronounced, the presented ephemerides (Table~2) were obtained by 
fitting the data in the last approximately linear section of the ($O-C$) 
diagram.
The orbital periods of some of the presented binaries (e.g., AB And, BX And, 
V523 Cas, SV Cam, VW Cep, EF Dra, SW Lac, XY UMa) are modulated by the presence of further component(s) in the system. 
Hence, the linear ephemerides of these systems are expected to be valid
with a sufficient precision (0.01 - 0.02 in phases) only during few years. 

{\it Acknowledgements:} This study was supported by VEGA grant 1157/2002 of the
Slovak Academy of Sciences.

\references

Ghedini, S., 1982, {\it Software for Photometric Astronomy}, Willmann-Bell Publ.\ Comp., Richmond

Kom\v{z}\'{\i}k, R., 2000, {\it private communication}

Kreiner, J.M., Kim, C.W., Nha, I.L., 2001, {\it An atlas of $O-C$ diagrams of 
eclipsing binary stars}, Wydawnictwo Naukove AP, Krak\'ow

Pribulla, T., Tremko, J., Rovithis-Livaniou, H., Rovithis, P., 2001, {\it 
Odessa Astronomical Publications}, {\bf 14}, 74

\end{document}

