Letter from the Publisher

UNNING EqUATIoN of TIME ModElS
distinctly more user-friendly yet far more complex in terms of their
construction, “running” equation of time watches have two hands fitted
coaxially with the minute hand, respectively indicating mean time and true
time. They require no mental arithmetic, since true time is continuously
displayed directly on the dial. This system, which had long been regarded as the
exclusive preserve of pocket-watches, first appeared on wristwatches in 2004
and represents a genuine feat in terms of miniaturization. The Gyrotourbillon 1
by Jaeger-leCoultre, which caused a sensation mainly because of its spherical
tourbillon (see Tourbillon chapter), also features an offset hour/minute
subdial bearing a running equation of time displayed by an additional minute
hand adorned with a tiny golden sun. The Equation marchante “le Brassus”
by Blancpain is also distinguished by its double equation of time display:
the running equation of time itself appears in the center with an additional
central minute hand tipped with a golden sun; and a subdial at 2 o’clock boasts
a retrograde hand indicating the number of minutes of difference. This
sophisticated device is combined with an ultra-thin perpetual calendar.
Blancpain has also associated a running equation of time display and a perpetual
calendar in a model from the Villeret collection named
“Equation marchante pure,” but without any
additional segment-type display.
• 402 Grand Complications, Vol. VII
left
Jaeger-LeCoultre ,
Gyrotourbillon 1
right
Blancpain, Equation
marchante “Le Brassus”