Seiko 7T94 Manual - Page 17

English TELEMETER (for models with telemeter scale on the dial) ● The telemeter can provide a rough indication of the distance to the source of light and sound. ● The telemeter indicates the distance from your location to an object that emits both light and sound. For example, it can indicate the distance to the place where lightning struck by measuring the time elapsed after you see a flash of lightning until you hear the sound. ● A flash of lightning reaches you almost immediately while the sound travels to you at a speed of 0.33 km/second. The distance to the source of the light and sound can be calculated on the basis of this difference. ● The telemeter scale is so graduated that the sound travels at a speed of 1 km in 3 seconds.* *Under the condition of temperature of 20°C(68°F). CAUTION The telemeter provides only a rough indication of the distance to the place where lightning struck, and therefore, the indication cannot be used as the guideline to avoid the danger of lightning. It should also be noted that the speed of the sound differs depending on the temperature of the atmosphere where it travels.