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mark a certain altitude, which is graphically shown by the segments on the circumference, to get an
intermediate difference measurement. However, the bezel is mainly related to the compass function.
Where do I find the correct declination for my area so I can set my Wristop
Computer?
Local declination, either E or W, is usually marked on maps with either one-degree or half-degree
accuracy.
EFFECT OF AIR TEMPERATURE ON ALTITUDE MEASUREMENT
The atmospheric pressure means the weight of air mass above the observer: at a higher altitude there
is less air than at a lower altitude. The principle of an altimeter is to measure the different air
pressure between different altitudes.
The air weight is affected by the outside temperature. Consequently the air pressure difference
between two altitudes is also dependant on temperature.
The altitude calculation of Wristop Computer is based on the air pressure at certain normal temperatures.
Each altitude has a definitive normal temperature. The normal temperatures at each altitude are
presented in table 1.
Altitude (m) Altitude (ft) Temperature (C) Temperature (F)
above sea level above sea level
0 0 15.0 59.0
200 656 13.7 56.7
400 1312 12.4 54.3
600 1969 11.1 52.0
800 2625 9.8 49.6
1000 3281 8.5 47.3
1200 3937 7.2 45.0
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