COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                      Number 1168

                                 Konkoly Observatory
                                 Budapest
                                 1976 August 16



         THE LONG-TIME VARIABILITY OF AN UMa


According to Shugarov (Astr.Tsirk. 888, 7) AN UMa is an eclipsing
binary with P = 0.1595d. This result was confirmed by Mumford
(IBVS 1133). Meinunger and Wenzel (VSS 7, 405) found for this star
a long-time variability which on all levels of brightness is 
superposed by fast variations.
In the meantime further plates of the field psi UMa were taken at
Sonneberg. The figure shows the long-time variations of AN UMa on
our plates.
Probably these variations are caused by a mechanism like that in
the R CrB-stars, i.e., a system of clouds of variable opacity 
around the whole system.

                     [FIGURE 1]


                                L. MEINUNGER

                            Sonneberg Observatory
                    of Central Institute for Astrophysics
                     of Academy of Sciences of the GDR