Fichier:Shortt_Synchronome_free_pendulum_clock.jpg
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Description
DescriptionShortt Synchronome free pendulum clock.jpg |
English: A Shortt-Synchronome free pendulum clock belonging to the US National Institute of Standards and Technology (NIST), in the NIST Museum, Gaithersburg, Maryland, USA. Invented in 1921 by William Hamilton Shortt, it was the most accurate mechanical clock ever manufactured, achieving an accuracy of around one second per year. This example was purchased by NIST in 1929 and used by physicist Paul R. Heyl in his second determination of the gravitational constant. It consists of a master invar pendulum (left) in a copper vacuum tank and a precision pendulum clock (right). The units are connected by electric wires that operate electromagnets to keep the slave pendulum in the clock synchronized to the master pendulum. The pendulum in the clock is attached to the clock's mechanism and performs the function of moving the clock's gears, leaving the master pendulum to swing virtually free of outside influence. The pendulums make one swing per second, and every 30 swings the slave clock gives the master pendulum a push to keep it swinging. Alterations to image: brightened slightly, changed from GIF to JPEG. |
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Autorisation (Réutilisation de ce fichier) |
Public domain because it is work of the US National Institute of Standards and Technology. Copyright notice on the website: "These World Wide Web pages are provided as a public service by the National Institute of Standards and Technology (NIST). With the exception of material marked as copyrighted, information presented on these pages is considered public information and may be distributed or copied" |
Conditions d’utilisation
Public domainPublic domainfalsefalse |
This image is in the public domain in the United States because it is a work of the United States Federal Government, specifically an employee of the National Institute of Standards and Technology, under the terms of Title 17, Chapter 1, Section 105 of the US Code.
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Historique du fichier
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Date et heure | Vignette | Dimensions | Utilisateur | Commentaire | |
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actuel | 14 juin 2019 à 19:34 | 2 700 × 3 600 (882 kio) | Hohum | New upload, same clock, NIST | |
30 décembre 2009 à 13:35 | 300 × 378 (20 kio) | Chetvorno | {{Information |Description={{en|1=Description={{en|1=A Shortt-Synchronome free pendulum clock belonging to the US National Institute of Standards and Technology (NIST), in the NIST Museum, Gaithersburg, Maryland, USA |
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