Obituary Jürgen Stock 1923–2004

Jürgen Stock passed away last April 19th at the age of 80. He was born and educated in Germany, where he got his doctoral degree in 1951 from the University of Hamburg; he developed his scientific career in different observatories in Germany, USA, South Africa, Chile, and Venezuela. His fresh approach to scientific problems and unrivaled taste for tackling big technical challenges made him an expert in several fields of astronomy, with incursions into geodesy and meteorology. Jürgen made significant contributions in the fields of astrometry, astronomical photography, stellar spectroscopy, spectral classification, galactic structure, stellar radial velocity determinations from Schmidt telescope objective prism plates, origin and measurement of the atmospheric seeing, application of astrometric techniques to plate tectonics, and, most of all, site testing for astronomical observatories.

No doubt, the astronomical community the world over is in debt with Jürgen for the period of his life from 1960 to 1964 that he spent in Chile climbing mountains on horseback searching for an adequate site for an astronomical observatory, which ended up with the discovery of the privileged conditions for astronomical observation of Cerro Tololo and nearby mountains. Jürgen not only selected the site, he was instrumental in the construction of the road to the top, of the observatory itself, and became the first director of CTIO. The euphoric reports that Jürgen sent periodically to AURA, now known as the Stock Reports, will soon be edited and published for the benefit of the interested public. Meanwhile, Jürgen had kept informed his European contacts of his findings, especially Otto Heckman, his former thesis supervisor. In late 1963 Jan Oort wrote to Heckman concerning the wise decision by ESO to build its observatory in Chile instead of South Africa..... The worst thing is that we need some extra time to check the quality of the mountain and to construct a road to the top – and we should always keep in mind, that we don’t have a Dr. Stock. Or to put it in Jürgen own words..... As a result of this effort, the world’s largest collection of astronomical instruments is now in Chile.

From 1966 to 1970, after ending his term at CTIO in 1965, he worked in the Departamento de Astronomía of the Universidad de Chile in Santiago, where he was the thesis supervisor of several students. In1971 Jürgen moved to Venezuela, where at the age of 48 he was involved again in the construction of a new astronomical observatory in Llano del Hato, near Mérida, and four years later he became the founding director of the Centro de Investigaciones de Astronomía(CIDA), a position that he held until 1982. The 33 years that Jürgen worked at CIDA were fundamental for the establishment of astronomy as a professional scientific discipline in Venezuela. Until the last moments of his life, he contributed his share towards this goal with his continuous dedication to the education and training of professional astronomers, and became a reference point for young scientists in search of advise from an expert. Foreign visitors frequently came to CIDA to collaborate with, or be taught by Jürgen.

In total, Jürgen lived more than half of his life in Latin America. During his childhood, from the age of 2 to 6, he and his family lived in Mexico City. In fact, Spanish was his first language and it was during this period that he became acquainted with the Latin culture. It should then come as no surprise that it was in Chile and Venezuela where he brought up his family with great dedication. The terrible experiences that he lived at age 16 when he was sent involuntarily to the Russian front during the Second World War marked his character for life, making him a modest and humble man, with a clear concept of what is important in life. He would use his life experience, together with anecdotes and stories from the time of the war, to dictate moral and social values to his children.

He is survived by his Chilean wife Silvia, three daughters and two sons, Jeanette, Bernhard, Frances, born in Chile, and Josephine and Eckhard, born in Venezuela, and five grandchildren, Natalie, Christine, Nicole, Jürgen-André, and Sarah.

We will all miss Jürgen as a colleague, as a friend, as a father, as one of the last pioneers of our science.

Gustavo Bruzual and M. Jeanette Stock