\documentstyle[epsf]{article}
\input ibvs.sty

\begin{document}
\IBVShead{4381}{9 October 1996}

\title{New Elements of V628~Cygni}
\vspace{-1em}
\centerline{[BAV Mitteilungen Nr.\,89]}
\vskip 8mm

\begintext

V628~Cyg = S~4554 Cyg was discovered by Hoffmeister (1949) on
photographic plates of the Sonneberg Observatory. He classified the
star as an Algol-type variable in the range between 13\fm 0 and 13\fm 5. First
investigation of this variable was performed by Rohlfs (1950, 1951). She
provided a photographic light curve, reclassified the variable as a W~UMa-type 
and determined first elements as:
\vskip 1mm
\hspace*{3cm}Min\,I = HJD\,2427955.138 + 0\fd 651650 $\times$ E \hfill(1)
\vskip 1mm

A few years later Romano (1967) investigated V628 Cyg again.
He derived 9 minima and improved the elements of Rohlfs as follows:
\vskip 1mm
\hspace*{3cm}Min\,I = HJD\,2427955.138 + 0\fd651652 $\times$ E\hfill(2)
\vskip 1mm

Moreover Romano determined the range of variability between 
12\fm 2 and 12\fm 7 (phg) in the primary and between 12\fm 2 and
12\fm 5 (phg) in the secondary minimum.

With this data V628 Cyg is listed in the fourth edition of the GCVS
(Kholopov et al. 1985). For a quarter of a century the variable had remained 
obviously unobserved, when we put V628 Cyg on our observing program.
The CCD observations were made with SBIG ST6 cameras without filters,
attached to a 32cm RC telescope (W.M.) and a 20cm SC telescope (F.A.).
GSC\,3595.1630 served as comparison star and several other stars in the
same field were used to check its constancy.
In our instrumental system the amplitude of
variability is 0\fm60 for the primary minima and 0\fm52 for the secondary
minima.

A period analysis program, based on the algorithm of 
Schwarzenberg--Czerny (1989) showed that the period given in the GCVS
is a spurious one with the relation
\[\rm\frac{1}{p'}-\frac{1}{p} = \frac{1}{2}\]
Using all available minima a weighted least squares fit led to the new 
elements:
\vskip 1mm
\hspace*{3cm}Min\,I = HJD\,2449177.4629 + 0\fd 96659115 $\times$ E\hfill(3)
\hspace*{78mm}$\pm$4 \hspace*{20mm}$\pm$5
\vskip 1mm     

All our times of minimum light were determined with the Kwee--van Woerden (1956) method. 
\vfill \eject

\centerline{2}

\epsfysize=9.5cm
\centerline{\epsffile{4381-f1.ps}}
\centerline{
Figure 1. Differential light curve of V628~Cyg drawn with the new
ephemeris (3)}

\epsfysize=10cm
\centerline{\epsffile{4381-f2.ps}}
\centerline{Figure 2. O$-$C diagram for V628~Cyg using the new
ephemeris (3).}

 $\bullet$ represents  photoelectric, $\circ$ photographic series, + visual
 observations and $\Box$ photographic plate minima.
\vfill \eject

\centerline{3}
\vskip 1mm
\begin{center}
Table 1. Observed times of minima for V628 Cyg, epochs and residuals
 computed with respect to the linear ephemeris (3) derived in this paper.
\vskip 1mm
\small
\begin{tabular}{ccccccccclrlc}
\hline
JD hel.&W&T$^{\star}$&Epoch&(O$-$C)&Lit& &JD hel.&W&T$^{\star}$&Epoch&(O$-$C)&Lit\\
2400000+& & & & & & &2400000+& & & & & \\
\hline
\\
 27955.439&1&P&$-21956$.5&$-0$.032&[1]& &32862&359.3&V& $-16879$.0 &$-0$.012  & [2] \\
 27983.471&1&P&$-21927$.5&$-0$.031&[1]& &32865&301.3 &V  &$-16876$.0 &$+0$.030  &[2] \\
 28285.565&1&P&$-21614$.0&$+0$.003  &[1]& &37130&489.1 & P & $-12454$.0 &$-0$.048  & [3] \\
 28344.467&1&P&$-21553$.0&$-0$.057  &[1]& &37517 &455.1 & P & $-12063$.0&$-0$.019  & [3] \\
 28404.461&1&P&$-21491$.0&$+0$.009  &[1]& &37530 & 511.1 & P & $-12050$.5&$-0$.012  & [3] \\
 28778.465&1&P&$-21104$.0&$-0$.058  &[1]& & 37547& 440.1 & P & $-12032$.0&$+0$.002  & [3] \\
 28779.464&1&P&$-21103$.0&$-0$.026  &[1]& &37549 & 444.1 & P & $-12030$.0&$+0$.073  & [3] \\
 29109.525&1&P&$-20762$.5&$-0$.056  &[1]& &37560 & 462.1 & P & $-12019$.5&$-0$.025  & [3] \\
 29111.515&1&P&$-20760$.5&$+0$.001  &[1]& &37848 & 545.1 & P & $-11721$.5&$+0$.014  & [3] \\
 29112.455&1&P&$-20759$.5&$-0$.026  &[1]& &37936 & 491.1 & P & $-11630$.5&$-0$.000  & [3] \\
 29158.376&1&P&$-20711$.0&$-0$.018  &[1]& &37938 & 410.1 & P & $-11628$.5&$-0$.014  & [3] \\
 29187.378&1&P&$-20681$.0&$-0$.013  &[1]& &47671 & 507.5 & F & $ -1558$.0&$-0$.007  & [4] \\
 29401.479&1&P&$-20460$.5&$-0$.012  &[1]& &47744 & 489.1 & F:& $ -1483$.5&$-0$.003  & [4] \\
 29431.472&1&P&$-20429$.5&$+0$.016  &[1]& &48500 & 398.1 & F:& $  -701$.5 &$+0$.032  & [5] \\
 29579.342&1&P&$-20276$.5&$-0$.002  &[1]& &48801 & 460.5 & F & $  -389$.0&$+0$.001  & [5] \\
 30378.257&1&P&$-19449$.0&$+0$.025  &[1]& &49119 &4667.10& E & $   -60$.0&$-0$.0007 & [6] \\
 30516.451&1&P&$-19306$.0&$-0$.003  &[1]& &49177 &4637.10& E & $     0$.0&$+0$.0008 & [6] \\
 30587.510&1&P&$-19233$.5&$+0$.011  &[1]& &49555 &4011.10& E & $   391$.0&$+0$.0011 & [7] \\
 31074.244&1&P&$-18729$.0&$+0$.067  &[1]& &49568 &4489.10& E & $   404$.5&$-0$.0001 & [7] \\
 31327.417&1&P&$-18467$.0&$-0$.007  &[1]& &49630 &3112.10& E & $   468$.5&$+0$.0003 & [7] \\
 32820.350&3&V&$-16923$.5&$+0$.026  &[2]& &49637 &5596.10& E & $   476$.0&$-0$.0007 & [7] \\
 32827.569&3&V&$-16915$.0&$-0$.005  &[2]& &49639 &4933.10& E & $   478$.0&$-0$.0002 & [7] \\
 32830.490&3&V&$-16912$.0&$+0$.017  &[2]& &49658 &3437.10& E & $   497$.5&$+0$.0017 & [7] \\
 32831.442&3&V&$-16911$.0&$+0$.002  &[2]& &49688 &3052.10& E & $   528$.5&$-0$.0011 & [8] \\
 32832.411&3&V&$-16910$.0&$+0$.004  &[2]& &50000 &5127.10& E & $   851$.5&$-0$.0026 & [7] \\
 32833.387&3&V&$-16909$.0&$+0$.014  &[2]& &50291 &4563.10& E & $  1152$.5&$-0$.0029 & [8] \\
 32835.301&3&V&$-16907$.0&$-0$.005  &[2]& & & & & & & \\
\hline
\end{tabular}
\end{center}

\vskip 2mm
\normalsize 
\noindent
$^{\star}$ P\, denotes photographic minima, V\, visually observed,\\
\hspace{2mm} E\, CCD observed minima and F photographic series.\\
Those marked with \lq :\rq\ got reduced weight.\\
\large
\vskip 1mm
\normalsize
[1]: E.~Rohlfs: VSS 1, 487,
[2]: C.~Hoffmeister: VSS 1, 487,
[3]: G.~Romano: MSAI 38, 16,
[4]: W.~Moschner \& W.~Kleikamp: BAVM, No.\, 56,
[5]: W.~Moschner \& W.~Kleikamp: BAVM, No.\, 68,
[6]: W.~Moschner: BAVM, No.\, 68,
[7]: W.~Moschner: this paper,
[8]: F.~Agerer: this paper.
\large
\vskip 4mm 
The individual measurements can be requested and will be sent
via e-mail.
\vskip .8cm

\beginauthors
\authorsrightcol
 F.~AGERER
 W.~KLEIKAMP
 W.~MOSCHNER
 Bundesdeutsche Arbeitsge\-mein\-schaft
 f\"ur Ver\"anderliche Sterne e.V. (BAV)
 Munsterdamm 90,
 D-12169 Berlin, Germany
\endauthors

\vskip 2mm
E-mail: 

agerer.zweik@t-online.de,                            %email


wilhelm.kleikamp@t-online.de,                             %email


wolfgang.moschner@t-online.de                            %email

\vfill \eject

\centerline{4}
\vskip 1mm

\begin{references}

Hoffmeister, C.: 1949, {\it Erg. AN}, {\bf 12}, 1

Kholopov, P.~N.~et al.: 1985, General Catalogue of Variable Stars,
4th Edition, Nauka, Moscow

Kwee, K.~K., van Woerden, H.: 1956, {\it Bull.~Astr.~Inst.~Netherlands}, {\bf 12}, 32

Rohlfs, E.: 1950, {\it Mitteilungen \"uber ver\"anderliche Sterne (Sonneberg)}, No.\,121

Rohlfs, E.: 1951, {\it Ver\"offentlichungen der Sternwarte zu Sonneberg},
{\bf 1}, (5) 487

Romano, G.: 1967, {\it Asiago Contr.}, No.\,193

Schwarzenberg-Czerny, A.: 1989, {\it Monthly Notices R. Astr. Soc.},
{\bf 241}, 153

\end{references}

\vskip 1cm
\centerline{\bf EDITORS' NOTE}
\vskip 1cm
\noindent Mr. Anton Paschke called our attention that the new RR Lyrae-type variable
GSC\,2576\_466 discovered by Gladders and Robb (see IBVS No.\,4350) is
identical with the new variable No.\,22 discovered by Antipin (IBVS No.\,4343).
The two notes have been published so close in time that they are undoubtedly
independent discoveries.

\end{document}
