Swiss pocket watch with calendar and equation of time Circa 1795

Very fine pink gold gentleman’s pocket watch
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A Swiss very fine gentleman’s pocket watch with calendar and equation of time, circa 1795.
18 Carat pink gold polished case with case maker’s punch mark ALH. Enamel dial with Arabic numerals on eccentric hour indicator, central sun hand for the equation of time, two subsidiary chapter rings indicating date and month with the number of days, and gold hands. Keywind, fire gilt full plate movement with chain/fusee, virgule escapement, three-arm brass balance, fine florally engraved and pierced balance bridge.
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Diameter: 54 mm
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Weight: 108 g
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Signed: No name
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The equation of time describes the discrepancy between two kinds of solar time. These are apparent solar time, which directly tracks the sun’s motion, and mean solar time, which tracks a fictitious mean sun with noons 24 hours apart. Apparent (or true) solar time can be obtained by measurement of the current position (hour angle) of the Sun or indicated (with limited accuracy) by a sundial. Mean solar time, for the same place, would be the time indicated by a steady clock set so that over the year, its differences from apparent solar time average to zero.