Janvier No. 309, circa 1796. Very fine and unusual mahogany veneered, one month going, astronomical, sideral and lunar clock, with the phase of the moon. | Important Wristwatches, Watches & Clocks | Geneva, Hotel Des Bergues, 17th October 1992

Important Wristwatches, Watches & Clocks

Geneva, Hotel Des Bergues, Oct 17, 1992

LOT 359

Janvier No. 309, circa 1796. Very fine and unusual mahogany veneered, one month going, astronomical, sideral and lunar clock, with the phase of the moon.

CHF 45,000 - 55,000

Sold: CHF 51,750

C. Rectangular, with sliding back panel, ormolu Sphynges on each side of the base and gilt brass engine-turned bezel. D. Silver chapter ring with twice twelve hours in Roman numerals, each divided in 6 ten minute divisions, the subsidiary inner ten minute dial, divided into 6 ten second divisions and showing sidereal minutes, the sidereal hours, shown by the gilt brass hand with a star burst. This latter hand revolves in 24 sidereal hours, the hand with the revolving moon, coincides with the star hand, once every lunar month. The revolving moon, driven from the center, having an arbor running down the rear of the hand's stem, rotates to show the age and phase of the moon. M. Gilt brass full plate round movement with turned pillars, going barrel, anchor escapement, short pendulum with silk suspension. Signed on the dial and the back plate. In very good condition. Dim. 31.5 x 18.5 x 15 cm

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Notes

Sidereal time: The standard used by astronomers, is measured by the diurnal rotation of the earth, which turns on its axis in 23 hours, 56 minutes and 41 seconds. The sidereal day is therefore 3 minutes, 56 seconds less than the mean solar day. One sidereal minute worth: 59'83611 seconds of the mean time, and the sidereal second: 0. 9972685. One can imagine, the clock was constructed for an astronomer who wished to study the moon. The main hands would indicate, the position of the moon in relation to a particular star, such as the first point of Aries.