\documentstyle[twoside, epsf, ibvs2, ibvse]{article}

\begin{document}

\IBVShead{5602}{17 February 2005}

\IBVStitle{CCD Minima for Selected Eclipsing Binaries in 2004}

\IBVSauth{Nelson, Robert H.}

\IBVSinsto{1393 Garvin Street, Prince George, BC, Canada, V2M 3Z1; e-mail: bob.nelson@shaw.ca}


\begintext

\IBVSEobs{Sylvester Robotic Observatory (SRO):  33 cm f/4.5 Newtonian on Paramount GT-1100s mount}

\IBVSEdet{SBIG ST-7e, Kodak KAF-0401E, 9 $\mu$m $\times$ 9 $\mu$m,\\
&       FOV 15\farcs8 $\times$ 10\farcs5\\
& SBIG ST-9, KAF-0261E, 20 $\mu$m $\times$ 20 $\mu$m,\\
&       FOV 11\farcs9 $\times$ 11\farcs9\footnotemark[1]\\
& SBIG ST-7XE, Kodak KAF-0402ME, 9 $\mu$m $\times$ 9 $\mu$m,\\
&       FOV 15\farcs8 $\times$ 10\farcs5\\
& All cameras were cooled to $-10\deg > T > -30\deg$ C
}
\footnotetext[1]{With x2 tele-extender lens}

\IBVSEred{Aperture photometry using MIRA Pro 7, by Axiom Research.\\
Digital tracing paper method, bisection of chords, curve fitting, and (occasionally) Kwee and van Woerden (1956).}

{\small
\IBVSEmins{
BF Aur	& 53010.7487	& 0.0002	& I	& c	& ST-7e\\
V776 Cas& 53351.7116	& 0.0001	& I	& V	& ST-7XE\\
SU Cep	& 53144.8552	& 0.0001	& I	& V	& ST-9\\
EG Cep	& 53187.8343	& 0.0001	& I	& R	& ST-7XE\\
XZ CMi	& 53010.8555	& 0.0003	& II	& c	& ST-7e\\
RW Com	& 53007.94105	& 0.00005	& II	& c	& ST-7e\\
RW Com	& 53008.06044	& 0.00005	& I	& c	& ST-7e\\
EK Com	& 53093.7813	& 0.0001	& II	& c	& ST-7e\\
BI CVn	& 53095.7933	& 0.0002	& II	& c	& ST-7e; Sine $O-C$ relation\footnotemark[4]\\
V0628 Cyg& 53172.8647	& 0.0003	& I	& c	& ST-7XE; Abrupt period change?? \footnotemark[4]\\
V0700 Cyg& 53261.7653	& 0.0002	& I	& c	& ST-7XE; Piecewise linear $O-C$ plot\footnotemark[4]\\
V0859 Cyg& 53141.8049	& 0.0005	& II	& c	& ST-9\\
V1130 Cyg& 53139.7936	& 0.0001	& I	& c	& ST-9\\
EX Del	& 53160.8803	& 0.0001	& I	& c	& ST-7XE; New period, 0.3309880 d \footnotemark[4]\\
AR Dra	& 53007.83558	& 0.00005	& I	& c	& ST-7e\\
CV Dra	& 53093.8837	& 0.0003	& II	& c	& ST-7e\\
YY Eri	& 53024.6709	& 0.0001	& I	& V	& ST-7e\\
}
}

{\small
\IBVSEmins{
SX Gem	& 53048.6821	& 0.0001	& I	& c	& ST-7e\\
AV Gem	& 53015.7747	& 0.0002	& I	& c	& ST-7e\\
QW Gem	& 53040.6172	& 0.0002	& I	& c	& ST-7e\\
SZ Her	& 53145.8592	& 0.0001	& I	& V	& ST-9\\
AK Her	& 53136.7703	& 0.0005	& I	& c	& ST-9\\
V0502 Her& 53082.0075	& 0.0002	& II	& c	& ST-7e\\
V0502 Her& 53121.8893	& 0.0002	& II	& c	& ST-7e\\
V0742 Her& 53090.895	& 0.001	        & II	& c	& ST-7e\\
V0842 Her& 53081.8388   & 0.0001        & I     & V     & ST-7e\\
V0842 Her& 53111.80053	& 0.00005	& I	& c	& ST-7e\\
V0878 Her& 53088.9686	& 0.0002	& I	& V	& ST-7e\\
V0921 Her& 53087.9381	& 0.0002	& I	& c	& ST-7e; Period uncertain\footnotemark[2]\\
V0342 Lac& 53166.8349	& 0.0003	& II	& c	& ST-7XE\\
Y Leo	& 53089.6776	& 0.0001	& I	& c	& ST-7e; Cyclic $O-C$ relation\footnotemark[4]\\
VZ Leo	& 53087.7141	& 0.0001	& I	& c	& ST-7e\\
AP Leo	& 53092.7672	& 0.0002	& I	& V	& ST-7e\\
AP Leo	& 53111.7045	& 0.0002	& I	& c	& ST-7e\\
BL Leo	& 53112.7145	& 0.0003	& II	& c	& ST-7e\\
CE Leo	& 53051.882	& 0.0001	& I	& c	& ST-7e\\
RT LMi	& 53006.9073	& 0.0001	& I	& c	& ST-7e\\
RZ Lyn	& 53047.6917	& 0.0003	& I	& c	& ST-7e\\
DF Lyr	& 53173.8661	& 0.0001	& II	& c	& ST-7XE\\
MZ Lyr	& 53138.868	& 0.001	        & I	& c	& ST-9\\
V0404 Lyr& 53159.79647	& 0.00005	& I	& c	& ST-7XE\\
IX Mon	& 53053.709	& 0.001	        & I	& c	& ST-7e\\
V2357 Oph& 53137.7985	& 0.0005	& II	& c	& ST-9\\
V0647 Ori& 53020.767	& 0.002	        & II	& c	& ST-7e\\
IM Per	& 53352.6518	& 0.0002	& II	& c	& ST-7XE\\
AS Ser	& 53143.7715	& 0.0003	& II	& c	& ST-9; Poor $O-C$ relation\footnotemark[4]\\
CX Ser	& 53143.8626	& 0.0004	& I	& c	& ST-9; Period uncertain\footnotemark[2]\\
V1123 Tau& 53020.5985	& 0.0002	& I	& c	& ST-7e\\
XZ UMa	& 53048.7928	& 0.0001	& I	& c	& ST-7e; Possible eccentric orbit\footnotemark[4]\\
TW UMa	& 53089.756	& 0.001	        & I	& c	& ST-7e\\
AA UMa	& 53040.7538	& 0.0003	& I	& c	& ST-7e\\
II UMa	& 53081.713	& 0.002	        & I	& V	& ST-7e\\
GI Vul	& 53132.9381	& 0.0002	& I	& c	& ST-7e\\
KN Vul	& 53160.7803	& 0.0003	& I	& c	& ST-7XE\\
NO Vul	& 53123.8924	& 0.0001	& I	& c	& ST-7e\\
GSC 3449-0680& 53058.68	& 0.001	        & II	& R	& ST-7e; Newly discovered variable\footnotemark[3 ]\footnotemark[4]\\
GSC 3449-0680& 53058.96	& 0.001	        & I	& R	& ST-7e\\
GSC 3449-0680& 53066.809& 0.001	        & I	& R	& ST-7e\\
GSC 3449-0680& 53074.938& 0.001	        & II	& R	& ST-7e\\
GSC 3449-0680& 53077.744& 0.001	        & II	& R	& ST-7e\\
}
}

\footnotetext[2]{Sparse data}
\footnotetext[3]{See IBVS 5600}
\footnotetext[4]{See ``Eclipsing Binary $O-C$ Files'' in the references}


\IBVSErem{
Attention is directed towards the website maintained by the author and others (see Eclipsing Binary $O-C$ Files below) that provides Excel files with times of minima and $O-C$ plots for some 1400+ eclipsing systems.  It is being continually updated and expanded.  Another very useful utility (see below) is the Eclipsing Binary Ephemeris Generator, maintained by Shawn Dvorak, which gives eclipse predictions visible at a specified location for a give night.}

\IBVSEack{
Thanks are due to Environment Canada for the website satellite views (see reference below) that were essential in predicting clear times for observing runs in this cloudy locale.  Thanks are also due to Attilla Danko for his ``Clear Sky Clocks'', (see below).  
This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France.}


\references

Danko, A., Clear Sky Clocks, {\tt http://cleardarksky.com/}

Dvorak, S., Eclipsing Binary Ephemeris Generator, \\
{\tt http://www.rollinghillsobs.org:8000/perl/calcEBephem.pl}

Kwee, K.K., \& van Woerden, H., 1956, {\it B.A.N.}, {\bf 12}, (464), 327-330

Nelson, R.H., Eclipsing Binary $O-C$ Files,  \\
{\tt http://www.aavso.org/observing/programs/eb/omc/nelson\_omc.shtml} 

Satellite Images for North America, {\tt http://gfx.weatheroffice.ec.gc.ca/}

\endreferences

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