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Magnetic declination = 1.3 deg E
sonic: Vazimuth = azimuth(magnetic) measured + declination - 90 (
Vazimuth is the direction that the sonic V axis is pointing), and is the rotation angle of horizontal wind components from instrument to geographic coordinates.
prop: azimuth = azimuth(magnetic) measured + declination + 180
prop azimuth is the angle that is added to the wind directions measured by the prop, so that they are relative to true north.