95th Auction
2017/5/6
Lot 146
Breguet, Movement No. 4113, 143 x 100 x 115 mm, circa 1940
An extremely rare Siderometre Type 101 with illumination and thermostat-controlled heating system
Case: aluminium. Dial: white. Movm.: brass movement, 2 barrels, gold screw compensation balance.
Siderometres were used in aviation in order to achieve fast positioning by displaying accurate sidereal time in an easily readable way.
The importance of these instruments is shown by an entry on the current Breguet web site (www.breguet.com/de/periodes-historiques/1864-1969): "The year 1939 is marked by the submission of the sidereal time-keeper patent. This goes hand-in-hand with the will of a company now submerged in the world of aviation, in keeping with the spirit established previously by Breguet with the navy. The sidereal time-keeper - or siderometer – is a precious instrument panel tool, of which about thirty units were purchased by the French Air Force and by the airline Air France."
Watch-Wiki explains the instrument as follows: To facilitate the calculations necessary for positioning, sidereal time is shown in degrees, minutes and seconds of arc of Earth’s rotation (as compared to hours, minutes and seconds of time). The dial has a centre seconds indication (actually 60 arc minutes), which accurately shows the measured period of time in arc minutes and 15 - 30 - 45 arc seconds. Arc degrees of sidereal time are displayed in three separate apertures, with a range of 000 to 360 (and reverting back to 000). The high quality gilt brass movement is fitted with two separate spring drives, one of them for the clock and the other for the digital dials.
(watch-wiki.org/index.php?title=Breguet_Siderometer_Type_102_(Nr._4379), as of 03/03/2017. The text also provides further information on the functionality of the instrument.)
An extremely rare Siderometre Type 101 with illumination and thermostat-controlled heating system
Case: aluminium. Dial: white. Movm.: brass movement, 2 barrels, gold screw compensation balance.
Siderometres were used in aviation in order to achieve fast positioning by displaying accurate sidereal time in an easily readable way.
The importance of these instruments is shown by an entry on the current Breguet web site (www.breguet.com/de/periodes-historiques/1864-1969): "The year 1939 is marked by the submission of the sidereal time-keeper patent. This goes hand-in-hand with the will of a company now submerged in the world of aviation, in keeping with the spirit established previously by Breguet with the navy. The sidereal time-keeper - or siderometer – is a precious instrument panel tool, of which about thirty units were purchased by the French Air Force and by the airline Air France."
Watch-Wiki explains the instrument as follows: To facilitate the calculations necessary for positioning, sidereal time is shown in degrees, minutes and seconds of arc of Earth’s rotation (as compared to hours, minutes and seconds of time). The dial has a centre seconds indication (actually 60 arc minutes), which accurately shows the measured period of time in arc minutes and 15 - 30 - 45 arc seconds. Arc degrees of sidereal time are displayed in three separate apertures, with a range of 000 to 360 (and reverting back to 000). The high quality gilt brass movement is fitted with two separate spring drives, one of them for the clock and the other for the digital dials.
(watch-wiki.org/index.php?title=Breguet_Siderometer_Type_102_(Nr._4379), as of 03/03/2017. The text also provides further information on the functionality of the instrument.)
estimated
23.000—30.000 €
Price realized
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