...
Magnetic declination = 1.3 deg E
sonic: Vazimuth = azimuth(magnetic) + declination - 90
(Vazimuth is the direction that the sonic V axis is pointing)
prop: azimuth = azimuth(magnetic) + declination + 180
...
Magnetic declination = 1.3 deg E
sonic: Vazimuth = azimuth(magnetic) + declination - 90
(Vazimuth is the direction that the sonic V axis is pointing)
prop: azimuth = azimuth(magnetic) + declination + 180