COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                       Number 896

                                   Konkoly Observatory
                                   Budapest
                                   1974 June 12


         POSSIBLE BEATS IN TWO DELTA SCUTI STARS


  Observations of two Delta Scuti suspects were obtained using
a 40 cm. reflector and a dry ice cooled 1P21. An OG-4 (4mm) filter
approximates the V magnitude. Observations were made differentially
between variable and comparison stars.
  Percy (J., 1973, R.A.S.C.J. 67, 139) has reported 18 UMa (HR 3662)
as a possible Delta Scuti star with a period of about 3 hours and
an amplitude of about 0.03 magnitude. This star has been observed
on four nights using 25 UMa (HR 3775) and 26 UMa (HR 3799) as 
comparison stars. On two nights the star was found to be variable with
amplitude and period in agreement with Percy's results. On the
remaining two nights no variation in 18 UMa was evident; the standard
deviation of the variable minus comparison magnitude differences
was about 0.003 magnitude which is about the same as the standard
deviation of the comparison minus comparison magnitude differences.
Thus the star was practically constant for 2.5 hours on one night
and 5.0 hours on another night.
  Percy also reports that either 24 Cnc (HR 3312/3) or 28 Cnc
(HR 3329) is variable with an amplitude of about 0.02 magnitude, and
a period of about 2.5 hours. Observations of both stars with 19 Cnc
(HR 3268) as a comparison star were obtained on four nights. From
these observations it is clear that 28 Cnc is the variable with a
period of about 2.3 hours and an amplitude which ranged from 0.025
magnitude to a few thousandths of a magnitude. The star 24 Cnc shows
some scatter but does not appear to have been variable with an 
amplitude greater than 0.005 magnitude on any of the four nights.
  Both 18 UMa and 28 Cnc are Delta Scuti stars. Both stars show
variations in amplitude that make the beat phenomenon a possibility.
Further observations of high quality are needed.

Joseph R. Grundy Observatory    S.J. HORAN
Franklin and Marshall College   J.L. MICHAEL
Lancaster, Pennsylvania 17604   M.A. SEEDS
U.S.A.