Philipp Matthäus Hahn

Philipp Matthäus Hahn (25 November 1739 in Scharnhausen (today part of Ostfildern), Duchy of Württemberg – 2 May 1790 in Echterdingen (today part of Leinfelden-Echterdingen)) was a German pastor, astronomer and inventor.

In about 1763 he devised a precision sundial, or heliochronometer that incorporated the correction for the equation of time.

[1] In 1774[2] he designed one of the earliest mechanical calculators of which two are known to have survived to the present day.

A renowned clockmaker, several horological museums display his works, including the Deutsches Uhrenmuseum which contains a mechanical orrery (planetarium) and a Weltmaschine by the "Priestermechaniker (priest mechanic)".

According to Reinhard Breymayer, Friedrich Schiller's verses "Brüder - überm Sternenzelt/ muß ein lieber Vater wohnen" ("Brothers, above the starry canopy/ There must dwell a loving Father"), reflecting the poet's Philosophy of Love, are a reference to the astronomer and pastor Hahn's Theology of Love.