Stührling Original Fine Luxury Timepieces

TACHOMETER or TACHYMETER

A scale on the dial, flange, or bezel of a chronograph that, in conjunction with the second hand, gives the speed of a moving object. The tachometer scale is calibrated to show the speed of a moving object, such as a vehicle, over a known distance. The standard length on which the calibration is based is always shown on the dial, e.g. 1,000, 200 or 100 meters, or ---- in somes cases ---- one mile. As the moving vehicle, for instance, passes the starting-point of the measured course whose length corresponds to that used as the basis of calibration, the observer releases the chrongraph hand and stops it as the vehicle passes the finishing point. The figure indicated by the hand on the tachometer scale represents the speed in kilometers or miles per hour.

TELEMETER
By means of the telemeter scale, it is possible to measure the distance of a phenomenon that is both visible and audible. The chronograph hand is released at the instant the phenomenon is seen; it is stopped when the sound is heard, and its position on the scale shows, at a glance, the distance in kilometers or miles separating the phenomenon from the observer. Calibration is based upon the speed at which sound travels through the air, approximately 340 meters or 1,115 feet per second. During a thunderstorm, the time that has elapsed between the flash of the lightning and the sound of the thunder is registered on the chronograph scale.

TOURBILLON PRINCIPLE

The purpose of the tourbillon is to compensate for the effects of gravity on a mechanical watch. When it is in a vertical position, a mechanical watch’s regulating organ – the balance, balance spring and escapement – undergoes imperceptible errors of rate with each oscillation, due to the effects of gravity. By housing the regulating mechanism in a cage rotating on its own axis, generally once a minute, a variety of vertical positions results, which compensate for each other, producing a very constant average rate and extreme running precision.

Though as good as moot in a wristwatch, this superb horological highlight is seen as a sign of technological know-how in the modern era. Its manufacture, one of the most complex and delicate, necessitates a perfect mastery of watchmaking and its techniques. Although this device is not absolutely necessary for accuracy purposes today, it is still appreciated as a complication of high-quality watches.