Seiko TELEMETER User Manual

TELEMETER

A

(for models with telemeter scale on the dial)

● The telemeter can provide a rough indication of the distance to the source of light

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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.

HOW TO USE THE TELEMETER

Before beginning, check that the stopwatch has been reset.

START

(Flash of light)

STOP

(Crash of thunder)

Approx. 3 km

Please note that the stopwatch second hand moves in 1/5 second increments and does not
always point exactly to the graduations of the telemeter scale. The telemeter scale can be used
only when the measured time is less than 60 seconds.

1

Press button A to start the
stopwatch as soon as you
see the light.

2

When you hear the sound,
press button A to stop the
stopwatch.

Read the telemeter scale

3

that the stopwatch second
hand points to.

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