Auroras rank among our planet’s most awe-inspiring natural phenomena: Fluorescent light cloaks the nocturnal darkness with mysterious green veils. With three of its most spectacular models, A. Lange & Söhne embarked on a journey to Iceland for a first-hand encounter with one of Mother Nature’s most fascinating extravaganzas, breathtaking impressions between light and darkness in primeval natural surroundings. Stunning luminosity that echoes the northern lights: Grand Lange 1 “Lumen,” Zeitwerk “Luminous” and Grand Lange 1 Moon Phase “Lumen.”
The interplay of opposites culminates in perfection with the northern lights in the Arctic sky above Iceland. For A. Lange & Söhne’s three luminous models, this is the ideal setting to showcase the spectacular contrast between light and darkness. The trio of fascinating light virtuosos that accompanied the Nordic expedition earlier this year included the Grand Lange 1 Moon Phase “Lumen,” which was first presented in January 2016. In addition to the Zeitwerk “Luminous” and the Grand Lange 1 “Lumen,” it is the third A. Lange & Söhne model with a semi-transparent sapphire-crystal dial. Its light-permeable coating allows the numerals to absorb a sufficient amount of light energy to uniformly glow in the dark for several hours.
Grand Lange 1 Moon Phase “Lumen”
Grand Lange 1 Moon Phase “Lumen”
The dial is made of blackened silver with generous apertures and a semi-transparent black-tinted sapphire-crystal glass wafer. The special coating applied to the glass blocks most of the visible light but not the UV spectra that “charge” the luminous pigments on the outsize date mechanism and cause them to glow in the dark. The tens cross is coated with a white luminous compound and printed with black numerals. Conversely, the units disc, also featuring black numerals, is made of transparent glass and rotates in front of the luminous background of the date aperture.
The lunar disc is made of glass. First, the glass surface is coated with a patented process. Then, 1164 stars and the moon are cut out with a laser beam. The luminous compound behind the lunar disc makes the moon and the stars shine. The large moon-phase display occupies a prominent position on the main dial. Once properly set, it only needs to be corrected by one day every 122.6 years.
Grand Lange 1 “Lumen”
How Luminous Displays Work
Watches with luminous displays need a light source that charges the luminous compound applied to the display elements and allows them to glow. Thanks to the semi-transparent black-tinted dial and an ingenious mechanism, the displays of the Grand Lange 1 Moon Phase “Lumen” and of the other A. Lange & Söhne “Lumen” models can be permanently charged with light energy.
Why the Northern Lights Are Green
The rare natural phenomenon can be observed in the polar region merely during a few days between September and March. Complex physical processes create the polychrome auroras in the upper strata of the Earth’s atmosphere. The green light, to which our eyes are particularly receptive, occurs at an altitude of about 100 kilometres. Here, oxygen atoms collide with the electrically charged particles of the solar winds. These collisions emit light with a wavelength of 557.7 nanometres, which the human eye perceives as green.