COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                      NUMBER 701

                                    Konkoly Observatory
                                    Budapest
                                    1972 July 31

              MU Cas - NOT AN RRs STAR


   30 photoelectric observations (1 P 21, integral light)
on July 18 1972 from 22h08m to 24h17m UT show no variations
in excess of 0.02 mag, the difference MU Cas minus comparison 
star having been constant - 0.27 +- 0.01 mag. For comparison 
served the star roughly 6' preceding the variable (see
chart by ROMANO of GR 13 in Treviso Pubbl. 17,p.40; MU Cas=
= S 4672). Thus Lange's statement (Astronomical Circular
USSR No. 542), the variability of MU Cas might be of ultra
short periodic type, probably is not correct: neither his
period (90 min.) nor the amplitude (0.6 mag.) could be 
verified.




Deutsche Akademie der Wissenschaften          W. WENZEL
Zentralinstitut fur Astrophysik
Sternwarte
DDR - 64 Sonneberg