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\IBVShead{4988}{21 November 2000}

\IBVStitle{First Photoelectric Observations of GQ Draconis}

\IBVSauth{Atay, Eray; Alis, Sinan; Keskin, M. Mustafa; Koksal, Sule; Saygac, A. Talat} 

\IBVSinsto{University of Istanbul, Faculty of Science, Department of Astronomy and Space Sciences,\\ \indent 34452 Universite-Istanbul, Turkey, email: mea\_ast@yahoo.com}

\SIMBADobjAlias{GQ Dra}{HD 158260}

\begintext

\IBVSTnam{GQ Dra = HIP 85277 = HD 158260}

\IBVSTcoo{17\hr25\mm29\fsec44}{+51\deg29\arcm35\farcs3}{2000}

\IBVSTobs{TUBITAK\IBVSfm\ National Observatory (TUG), 40-cm Cassegrain telescope}

\IBVSfoot{TUBITAK: The Scientific and Technical Research Council of Turkey}

\IBVSfig{9cm}{4988-f1.ps}{All nights observations in three filter. $B-0\fmm2$, $V$ and $R+0\fmm2$ plotted respectively}

\IBVSTdet{OPTEC, Inc.\ SSP-5A Photometer}

\IBVSTfil{Johnson $B$, $V$ and $R$}

\IBVSTcomp{BD +51\deg2234 = HIP 86191}

\IBVSTsysn

\IBVSTdata{Upon request}

\IBVSTtyp{ EB }

\IBVSTrem{
GQ Dra is a double star and the brighter companion is an EB type
eclipsing variable. Its variability was discovered by Hipparcos (ESA,
1997). We carried out photoelectric photometry of that variable. Mean $V$
band magnitude derived from Tycho photometry is 8\fmm94. The system has
a 0\fday765899 orbital period and a Hipparcos epoch is given as JD
2448500.5641 (ESA, 1997). GQ Dra was observed in 21, 22, 23, 24, 26,
29, 30 September and 1 October 2000 from TUBITAK National Observatory
by the authors Alis and Atay. HIP 86191 was used as a comparison star
which is defined constant by Hipparcos (ESA, 1997).  We made two times
10-second integrations in each filter. Each observation set contains
six variable and two comparison star measurements. Differential
atmospheric corrections were made in the usual way. The comparison star
has the same spectral type as the variable, therefore we did not use
the second-order extinction coefficients.  GQ Dra shows a Beta Lyrae
type light curve. The folded light curve is displayed on Figure~1 in
three filters.  During this observing session we observed one primary
and one secondary minimum. Times of minima were determined by the Kwee
and van Woerden (1956) method. The minimum times for $V$ band are given
below in Heliocentric Julian Date:
\begin{center} 
${\rm Min~I = HJD}~2451812.31325 \pm 0.00038$\\
$O - C~{\rm(Min~I)} = 0.0024$\\
${\rm Min~II = HJD}~2451 817.28809 \pm 0.00109$\\
$O - C~{\rm(Min~II)} = 0.0009$
\end{center}
}

\IBVSTack{We would like to thank TUBITAK National Observatory for their
kind support. This work is also supported by the Research Fund of
Istanbul University. Project no.\ OR-104/07032000.}

\references

ESA, 1997, The Hipparcos \& Tycho Catalogues, ESA SP--1200

Hardie, R.H., 1962, Stars and Stellar Systems, Vol.\ II, {\it Astronomical
Techniques}, (W.A. Hiltner, ed.) Univ.\ of Chicago Press,
Chicago, p.\ 178.

Henden, A.A. and Kaitchuck, R.H., 1990,
{\it Astronomical Photometry}, Willmann-Bell, Inc.

Kwee, K.K., and van Woerden, H., 1956, {\it B.A.N.}, {\bf 12}, 327


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