1575-1580, appointed to the Lutheran pastorate in Backnang, near Stuttgart. 1580, appointed professor of mathematics, Univ. of Heidelberg. 1584-1631, professor of mathematics, Univ. of Tuebingen, replacing Apian who had been dismissed for refusing to sign Lutheran oath of religious allegiance. Between 1588 and 1629, elected dean of Tuebingen arts faculty eight times. While a student he had been supported by a stipend from the Duke of Wuerttemberg, in order that he might be prepared for service in the Lutheran church.
Influence has to have been behind the professorial appointment, probably influence at court.
He made most of his own astronomical instruments, but was not involved in any kind of instrument trade. I won't list this because it does not involve the development of a new instrument.