COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1721

                                   Konkoly Observatory
                                   Budapest
                                   1979 December 21


   UBV PHOTOELECTRIC OBSERVATIONS OF V 1016 Cyg DURING 1979


   V 1016 Cyg (MHalpha 328-116) is considered as the prototype
of a small group of unusual variable stars.
   The properties of its remarkable emission-line spectrum
and details on its evolution have been given in the literature 
(see e.g. Mammano and Ciatti (1975), Ciatti et al. (1978),
Ciatti et al. (1979)). No accurate photoelectric photometry of
this interesting object has been secured up today. Prior to
1963 (when unusual nova-like brightening took place) photographic
observations showed the star was probably fainter than 15.5 pg
(Fitzgerald et al. 1966). In 1965 the variable reached 11.8 pg
rising slowly to 10.8-10.7 at the beginning of 1968 (Ciatti et
al. 1971). Since then the star has maintained a nearly constant
brightness (Ciatti et al. 1978).
   During 1979 UBV photoelectric observations of V 1016 Cyg
have been carried out at the 91 cm Cassegrain telescope of the
stellar station of the Catania Astrophysical Observatory using
BD +39deg3965 as comparison star and checking our measurements
with a set of standard stars. The comparison star has not shown
any noticeable variation. Our observations range from the 7th
July 1979 (J.D. 2444067) to the 9th November 1979 (J.D. 2444187).
   The reduction of observations to the standard UBV system
is in progress but the mean magnitudes of variable we found are
V=10.46, B=10.05 and U=9.99.
   In the Figure we report the magnitude differences
(V 1016 Cyg - BD +39deg3965) versus Julian Day for each night
of observation.
   From the Figure we can see that V 1016 Cyg is increased
almost constantly in its V luminosity of about 0.05 mag., from

			[FIGURE 1]

Delta m_V=~2.24 to Delta m_V=~2.19, while B and V magnitudes seem to be
constant.
   It is difficult to say if this V light curve is an increasing
part of a long period variable or if the star is increasing
indefinitely its V luminosity. There are, however, some indications 
for the latter hypothesis: the last photographic (1977) observations
by Ciatti et al. (1978) give values of 10.8 and 10.7 for B and V
magnitude, respectively. Our photoelectric observations, as we say
above, give mean values of 10.85 and 10.45 for B and V magnitudes.
This fact is consistent with the hypothesis that the star is increasing 
its V luminosity almost constantly (from 1977?) up today.

					E. MARILLI, G. STRAZZULLA
					Osservatorio Astrofisico di Catania
					Citta Universitaria
					95125 Catania - Italia

References:
Ciatti, F., Mammano, A., Rosino, L.: 1971, IAU Colloquium No. 15,
	Bamberg, 64 [BIBCODE 1971ndnf.coll...64C ]
Ciatti, F., Mammano, A., Vittone, A.: 1978, Astron. Astrophys. 68, 251 [BIBCODE 1978A&A....68..251C ]
Ciatti, F., Mammano, A., Vittone, A.: 1979, Astron. Astrophys.
	(Research Note, preprint)
Fitzgerald, M. P., Houk N., McCuskey, S. W.: 1966, Astrophys. J. 144, 1135 [BIBCODE 1966ApJ...144.1135F ]
Mammano, A., Ciatti, F.: 1975, Astron. Astrophys. 39, 405 [BIBCODE 1975A&A....39..405M ]