Swiss rare quality Ankerchronometer watch Circa 1883

Open faced gold pocket watch by Patek Philippe
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A Swiss very early and very rare quality “EXTRA”, Patek Philippe Ankerchronometer,  circa 1883.
Engine turned 18 Carat gold, “à goutte”, case with monogram and reeded mid section. Ankerchronometer movement, observatory quality “EXTRA”, very big chronometer balance, wolf’s toothing, gear train made of a special alloy, balanced lever, Geneva striping. White enamel dial with Roman hours, sunk subsidiary dial with Arabic seconds and original gold hands.
Matching number on case and movement, movement and dial signed.
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Diameter: 52 mm
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Weight: 113 g
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Signed: Patek Philippe & Co Genève
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Only the very best Patek Philippe movements got marked “Extra” or “Special” and were mostly made for testing purposes at observatories.