Tachometer Scale 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, as in this case, one mile. As the moving vehicle, for instance, passes the starting-point of the measured course whose length corresponds with that used as the basis of calibration, the observer releases the chronograph hand and stops it as the vehicle passes the finishing-point.
Telemeter Scale By means of the telemeter scale it is possible to measure the distance of a phenomenon which 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 on the speed at which sound travels through the air, viz, approximately 340 meters or 1,115 feet per second ).
For example, during a thunderstorm the time that has elapsed between the flash of lightning and the sound of thunder is registered on the chronograph scale.
Coming in March! We will have the new RGM Classic Chronograph Model #455. Less than 100 watches will be made with this classic 1940's inspired design.
•38.5 mm X 14.0 mm •Polished Stainless Steel •Sapphire Crystal •Blued Steel hands •2 dial options with the tachometer in black or red •Solid case back • RGM/ETA 7750 Automatic, 25 jewels, 28,800 . Rhodium, finished in - Cote de , •Strap option in tan or dark blue leather •List $3,900.00