Evolution of the Geminids observed over 60 years

Visual observations collected over 60 years ( 1944 - 2003) are analysed. The profiles and values of the population index near the activity peak are rather constant over the entire period and confirm the strong mass segregation within the stream. The peak activity is characterized by a plateau in the pro. le with a ZHR between 120 and 130 lasting for about 12 h between lambda(.) = 261.5 degrees and 262.4 degrees ( J2000). This is consistent with an age of the Geminid stream of about 6000 years. The position of this plateau is constant. Variations of the ZHR by more than 10% within the peak period are found in data of well-observed returns. These structures of about 0.2 degrees duration can be traced over more than a decade with an average drift of about) 0.02 degrees in solar longitude per year.