Rare Swiss deck chronometer with power reserve Circa 1908

Open faced silver deck watch by Longines
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An extremely rare deck chronometer with a 50h power reserve indicator, circa 1908. Accompanied with Longines extract from the archives and chronometer test certificate 1908.
Exceptionally infrequent chronometer calibre numbered two times as prescribed for deck chronometers, screwed gold chatons, fine adjusting device, Guillaume chronometer balance, and lever escapement. Original silvered dial with Roman radial hours, outer minutes track, subsidiary dial for the seconds, 50-hour power reserve indicator, and blued steel hands. Silver polished case with an applied monogram, gold crown and hinge. Case and movement with matching number.
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Diameter: 68 mm
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Weight: 250 g
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Signed: Longines
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This deck chronometer was tested at the Neuchâtel Observatory in 1908 and in Parisi in 1910, Observatoire du Parc de Montsouris Astronomie.