BREIL CHRONO FS20 Manual De Instrucciones página 11

F TELEMETER*
The Telemeter is a distance indicator wich allows distance to be calculated on the basis
of the speed of sound. It is useful, therefore, for aviation, navy, army and artillery
purposes. It can also measure how far away a thunderstorm is.
The hand is started the second a flash, smoke or lightning is seen and stopped when
the actual sound is heard. The distance, from 1 to 20 kilometres, between the observer
and the explosion or storm is read from the telemetry scale.
* Not available on all models.
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