The periods of MU Cephei

Period analysis of BAA-VSS and JAS/SPA observations of Mu Cephei shows that two main periods of 850 and 4400 days were present during the years 1959-1993. This result is in good agreement with periods found in earlier data. It is likely that the 730-day period given in the GCVS and that of 920 days found in subsets of the data are aliases of the 850-day period.