per Aspera ad Astra

(1964) I'm twenty years old and just finished my "candidaats"- exam. I'm coaching a "wiskundepracticum"-group of [first-year] students [one day a week] among them Henk Barendregt (1964) year one of the quiet sun, solar activity (1985) Halley's Comet Return

(1965) My elder daughter Helen becomes two years of age and this time my "practicum"-group of [second-year mathematics] students contains Gerard 't Hooft and Wim Hesselink (1965) year two of the quiet sun, van Allen's radiation belt (1958) World Geophysical Year

page dedicated to the memory of Rainer Hettich and Jowi de Roever
mathematicians, neighbors, wise men and friends

When friends tell us goodbye and wise men pass away,
there's emptiness inside
and in the open sky a cloud does hide
the stars that went astray.