COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                    Number 2017

                                 Konkoly Observatory
                                 Budapest
                                 1981 September 16

                                 HU ISSN 0374-0676




     NOTE ON PUBLISHED TIMES OF MAXIMA OF DY PEGASI

   Last year, Mahdy and Szeidl (1980) published a paper,
"Period Changes of Dwarf Cepheids, I: CY Aquarii, EH Librae,
DY Pegasi", in which our timings of maxima of DY Peg (Quigley
and Africano; 1979) were used. In Table I of our paper, we had
listed the 19 times of maxima we had measured at McDonald
Observatory. In Table II we had listed maxima observed by
earlier workers. Many of the earlier papers do not give times
of maxima but instead tabulate observed points of the light
curves. To determine the times of maxima from such tabulated
data, we had used a quadratic fitting procedure. The majority
of the maxima listed in our Table II were obtained by using
this fitting procedure.

   Mahdy and Szeidl concluded that our quadratic fitting
procedure introduced a systematic lag of 0.0005d. (We won't argue
the point here in this brief note.) Unfortunately, they applied
this 0.0005d correction to our 19 McDonald Observatory timings.
Since the McDonald data was in the form of high speed photometry
light curves (integration times of 2-5 sec), it was a simple
matter to determine the times of maxima directly from the
computer generated plots, and our quadratic fitting procedure
was not used. Thus, the "correction" applied by Mahdy and
Szeidl to the McDonald DY Peg maxima is definitely wrong. In
any future work incorporating this McDonald DY Peg data, the
original, uncorrected values listed in Table I of our paper
should be used.



ROB QUIGLEY             JOHN L. AFRICANO
Dept. of Physics and    Kitt Peak National Observatory
Astronomy               P.O. Box 26732
Western Washington      Tucson, AZ 85726 USA
University
Bellingham, WA 98225
USA


References:

Mahdy, H.A., and Szeidl, B. 1980, Mitteilungen der Sternwarte
   der Ungarischen Akademie der Wissenschaften, Budapest,
   No. 74. [BIBCODE 1980CoKon..74....1M ]
         [CoKon No. 74]
Quigley, R., and Africano, J.  1979, Pub. Astron. Soc. of the
   Pacific, 91, 230. [BIBCODE 1979PASP...91..230Q ]