German astronomical center seconds cylinder watch Circa 1785

Rose gold complicated watch by Philipp Matthäus Hahn
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A museum quality German 14 Carat rose gold open faced astronomical centre seconds cylinder pocket watch with calendar, circa 1785. Full plate movement, open barrel, cylinder escapement with a steel cylinder, large five armed brass balance with steel balance spring, open work balance bridge with regulator scale. White enamel dial, in the upper part to the left a subsidiary dial with the date in black Arabic numerals, the months and length of the months in red Arabic numerals, to the right radial time indication with Roman hours and outer Arabic quarter hour numerals, in the lower part a subsidiary dial showing the phases of the moon in combination with the duration of moonlight into red and black quarter segments and the planets associated with the days, an outermost main chapter ring with Arabic seconds. Plain case.
Dial and movement signed,
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Diameter: 62 mm
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Signed: Hahn à Echterdingen
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Weight: 132 g
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Philipp Matthäus Hahn was born on November 25^th, 1739 in Scharnhausen and he died on May 2^nd, 1790 in Echterdingen. He was a German avid protestant clergyman, astronomer, inventor and minister of the parishes Onstmettingen, Kornwestheim and Echterdingen, but also one of the most eminent precision mechanics and watch and clockmakers of the 18th century. Hahn produced a large number of high-quality pocket watches, most of them with calendar and moon phase indications. He made calendar movements of exceptional mechanical quality and attractive design. He also made hall clocks as well as astronomical bracket clocks. In about 1763 he devised a precision sundial or helio chronometer that incorporated the correction for the equation of time. Today his large observatory clock is one of the highlights of the clock museum in Furtwangen. Hahn was the first maker in Germany to use the cylinder escapement in his pocket watches. He further was very interested in the production of calculators and scales, in 1774 he designed one of the earliest mechanical calculators and laid the foundation for Württemberg’s industry of weighing machines, which still enjoys an international reputation today. His sons continued his work and signed their watches and clocks with the signature Hahn Hofmechanikus Stuttgart. Along with his sons Christoph Matthäus, Johann Georg, Christian Gottfried and Immanuel, Hahn’s brothers Georg David Polykarp and Egidius Stephanius Gottfried also worked temporarily in his workshop. The most notable makers in Hahn’s group were Jacob Auch, Georg Matthäus Burger, Georg Joseph Sandra, Philipp Gottfried Schaudt, Johann Gottfried Ewald Sechting, Mauritius Steiner and Christoph Friedrich Strubel.