COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1521

                               Konkoly Observatory
                               Budapest
                               1978 December 27



           NOTES ON FOUR VARIABLE STARS



YY Del

This well observed star was discovered by Hoffmeister, C. and
announced as an eclipsing binary (11.1m - 11.9m ph). The star was
suspected to have a variable period. Using 436 sky-patrol plates
(Sonneberg Observatory) I could derive linear elements for two
intervals:

        J.D. 2425000 - 2436100
        Min.(hel.)= J.D.2427685.391+0.7930882d E (EA)
    and J.D. 2436100 - 2443700
        Min.(hel.)= J.D.2438210.391+0.7930935d E (EA)
           (11.31m - 12.02m/11.35m ph; D = 0.19p)

AL Del

Hoffmeister, C. discovered this variable star in 1931. There are
not many observations of this star, only Jensch, A. (1938) and
Whitney, B.S. (1951) have published some times of minima. 
Observations on 131 plates of the Sonneberg 40 cm-astrograph (1940
to 1973) confirm the elements of the GCVS 1969. The star is
fainter than given in GCVS.

DM Del

This bright star was find to be variable by Hoffmeister, C. in
1935. Visual and photographic observations (Hartha Sky-Patrol)
were carried out in 1978.
From 12 newly observed minima I obtained the following improved
elements:
        Min.(hel.) = J.D. 2442685.302+0.8446733 E (E)
              (8.7m - 8.90m/8.86m ph)
Note that this elements satisfy all the observations published
except some minima of BBSAG.
Diethelm, R. derived new elements (BBSAG Bull. 27. 5. 1976) which
are clearly erroneous (see also for example Schneller's photoelectric 
observations in AN 285. 265, 1960).

BH Ser

This RR Lyrae-variable was discovered by Vyssotsky in 1941. 
Investigations of this star were carried out on Sonneberg Sky
Patrol plates from 1930 to 1977.
There has been a period-jump from 0.434545d to 0.4345527d in 1955.
The present elements are:
        Max.(hel.)= J.D. 2441482.427+ 0.4345527d E.

Further particulars will be published in "Mitteilungen der Bruno-
H.-Burgel-Sternwarte Hartha".





                         THOMAS BERTHOLD
                         Bruno-H.-Burgel-Sternwarte
                         DDR-7302 Hartha