An 18th century illustration of a compass in fine colour

An illustration of a compass, with a rose inside a square with foliate boders, with a needle pointing just west of north. It was engraved by Johann Christoph Berndt for the celestial atlas 'Mercurii Philosphici Firmamentum Firmianum', named for Thomas's patron, Leopold Anton von Firmian, Archbishop of Salzburg. Corbinianus Thomas (1694-1767), a Benedictine monk, was Professor of Mathematics and Theology at the University of Salzburg. His star atlas was first published in 1730 at Frankfurt, with a second edition at Augsburg the following year. He used an odd system for nomenclature: Bayer Greek letter for the star, Roman numeral for the magnitude and Arabic numeral for the star catalogue reference.