I would like to dedicate this paper to the memory of professor Edith A. Müller, deceased at the age of 77 a year ago, on July 24, 1995, until her retirement working at Geneva Observatory. She had been at the very beginnings of our IAU Commission 46 in the late sixties, she had been its President in 1970 when we all met during the General Assembly in Brighton, she always took great interest in further educational developments. I am personally grateful to her for much helpful advice during Commission 46 meetings at the General Assembly of 1985 in New Delhi. Wonderful teacher and organizer, she was also an extremely kind lady.