A silvered dial signed "Heele London Astro Physics Lab 46." Heele, a German maker of optical instruments, crafted this clock for the Astro Physics Laboratory 46 in London, as indicated on the dial. The movement features a heavy compensating pendulum with four ruby bearing axes and has a runtime of one week. The case is made of blackened oak with glass panels on the sides. The dial is divided into three sub-dials: a central minute hand, an upper seconds hand, and a lower hour hand marked on a 24-hour scale. A copper weight running along the side of the case powers the clock. The movement has a runtime of a week.
The clock is 129cm height, width: 34,5 cm and depth:23,5 cm.