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Eötvös Effect

The other Earth Rotation effect of interest in ballistics is the Eötvös Effect.  It is an east/west effect that produces a vertical deviation from the target.  Shots in an easterly direction impact high, and shots in a westerly direction impact low.  It is dependent on both latitude and azimuth (compass direction).  It is maximum at the equator, shooting either straight east or west, and vanishes to zero at the poles.

deflection (ft) = 0.000072722 * distance(ft) * Cos(latitude) * Sin(azimuth) * time of flight(seconds)

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Default values for the calculation are shown below.
Change any or all of the input variables for your particular shooting situation.

Latitude (degree)
Azimuth (degrees)
Distance (yards)
Time of Flight (seconds)



Eötvös Effect (Feet) + POI High, - POI Low

The vertical deviation in MOA is calculated using this equation supplied to me by ameteur Dutch physicist C. Teunissen. The beauty of this equation is that the answer is directly usable in a scope with bullet drop marked in moa.
Deviation (moa) = 0.25 * tof * cos(latitude) * sin(azimuth)


Deviation (MOA) + POI High, - POI Low