This mechanical marvel, of which 75 were produced, reproduces in miniature the movements of the Earth relative to the Sun and the stars. Its guilloché dial represents a star map. Driven by a flying tourbillon, it rotates once round the dial in 23 hours 56 minutes and 4 seconds, corresponding to one rotation of the Earth relative to the stars. Simultaneously a small sun rotates once round the dial in 24 hours exactly, to represent the Earth’s rotation relative to the Sun. The slight discrepancy between the two rotations gives the date and zodiacal calendar. And so as not to do things by halves, a minute repeater featuring Jaeger-LeCoultre’s latest innovations in the field of sound (crystal cathedral gong, trebuchet hammers) translates the time into sound at the owner’s discretion.