The encounters between timekeeping instruments and the selenographic exhibits in the collection of the Mathematics and Physics Salon emphasise the strong attraction of the moon in two related disciplines: astronomy and precision watchmaking.
In the 18th century, Dresden was not only a centre of precision watchmaking but also a hub of celestial observation and lunar research – of selenography, to be precise, the systematic mapping of the moon's surface. At the Mathematics and Physics Salon in Dresden’s Zwinger, astronomers used telescopes to create detailed maps of its visible topographic features. Today, milestones of lunar research in Saxony are on display in the scientific history collection of the museum that belongs to the Dresden State Art Collections. It reopened not long ago after renovation and is co-sponsored by A. Lange & Söhne.
Ever since the first astronomical clocks were built in the 14th century, it has been a declared objective in horology to emulate the progression of the moon as accurately as possible. The technical challenge involved in this complication is to ever more accurately approximate the lunar month of 29 days, 12 hours, 44 minutes, and 3 seconds. With a moon-phase display that needs to be corrected by merely one day every 122.6 years, A. Lange & Söhne has attained a highly realistic degree of accuracy.
Since 1994, the manufacture has presented twelve calibres with moon-phase displays. Among them are the LANGE 1 MOONPHASE and the 1815 RATTRAPANTE PERPETUAL CALENDAR, which had its debut this year.
It took Ernst Fischer of Dresden eleven years to sculpt the front side of the moon according to photographs and his own observations. Because the rotation of the moon is synchronised with that of the earth, it was impossible to map the "dark" side until it was orbited by the Soviet Union's Lunik 3 satellite in 1959. With a split-seconds chronograph, a perpetual calendar, a moon-phase display, and a power-reserve indicator, the 1815 RATTRAPANTE PERPETUAL CALENDAR unites more horological complications than the clearly organised dial suggests at first sight.
The world's longest refractive telescope – 35 metres long – is located in the observatory in Berlin-Treptow. It was established by Friedrich Simon Archenhold. The so-called moon medallions were inspired by his idea. With a ten-fold exaggeration of altitudes, the reliefs present a plastic rendition of the moon's topography. The horological charm of the LANGE 1 MOONPHASE lies in its remarkably accurate and fetchingly realistic display of the waxing and waning moon.
Working in Dresden, the astronomer and land measurer Wilhelm Gotthelf Lohrmann systematically observed the surface of the moon and in 1824 published his findings under the title "Topography of the Moon". In 1827, he was appointed chief inspector of the Mathematics and Physics Salon and later, as the director of the newly founded Technical Academy, one of Ferdinand A. Lange's teachers. The recently launched Lange model 1815 RATTRAPANTE PERPETUAL CALENDAR unites the technical fascination of a split-seconds chronograph with the precision of a perpetual calendar.
