Dr Svante Elis Stromgren (1870-1947), Professor of Astronomy at Copenhagen University, collaborated with the Danish watchmaker Jens Olsen (1872-1945) to create the display shown on this watch. The watch is made according to Olsen and Stromgren's patent which was first registered in Germany in 1914 (no.283094), followed by Switzerland in 1915 (no.73312), U.S.A. in 1916 (no.1187110) and Denmark in 1918 (no.22822). The display of mean and solar time is most unusual. Rather than incorporate a separate dial for sidereal time or a separate display for the equation of time within a subsidiary dial or sector, showing simply the difference in minutes + or - between solar and mean time, this watch has two concentric minute hands allowing both forms of time to be shown simultaneously upon the same dial using the same minute calibrations. As the watch runs, so the minute hand for sidereal time will advance ahead of or fall behind the mean-solar minute hand, thereby reflecting the actual difference in time between the two.
The two central minute hands may be advanced in tandem or separately - by depressing the crown, the hand setting may be placed into either tandem or single setting and the hand or hands moved using the hand-set pusher and crown in the usual manner. This rapid form of adjustment allowed the watch to be quickly and conveniently set.