Today on this April 15th, this beauty of a timepiece indicates the Equation of Time at zero, meaning that Apparent Solar Time (or True Sundial) is equal to Mean Solar Time (or Civil Hour). This occurs four times a year.
As of tomorrow, the indicator will move gradually to the left until May 14th and will return to zero again on June 12th and later on September 1st and December 24th.
That watchmakers manage to render a so complex celestial phenomenon in a mechanical watch is a proof of admirable know-how and mastery.
In Haute Horlogerie, Equation of Time (EoT) is rightly considered the most sophisticated and poetic of complications.
Here she is in all her glory...