The Dutch astronomer Jacobus Cornelis Kapteyn (1851-1922) founded a unique astronomical data analysis laboratory, helped compile a monumental star catalog, discovered the two star streams, and constructed a model of our galaxy.

Jacobus Kapteyn was born on Jan. 19, 1851, in Barneveld. At 18 he entered the University of Utrecht and 6 years later obtained his doctorate in physics. He became a professional astronomer somewhat accidentally: just as he received his doctoral degree, the position of observer at the Leiden Observatory became vacant. He applied and obtained it, a decisive event in his life, for it appears likely that it was during his subsequent 3 years at Leiden that he resolved to try to understand the structure of the universe. In 1878 he became professor of astronomy, calculus of probabilities, and theoretical mechanics at the University of Groningen. The following year he married Catharina E. Kalshoven; they had three children.

The University of Groningen...