Astronomic precession

[manucordier]

Ok thanks.

However it seems to me (but of course I am not en expert) that it is badly named because the term "astronomic precession" recalls much more the earth axis precession ( Astronomy: precession of earth ) than the "apparent wander" (or "earth rate drift", I believe both terms are synonyms, right ?).

One more question, do you agree Kieth with that one:

If we consider an aircraft flying from a point A to a point B:

Travel precession is synonym for transport precession = (LongitudeB - LongitudeA) * sin(mean lattitude)

and

Earth rate drift is synonym for apparent wander = (15°/h)*sin(mean lattitude)

Is that right ?

If what I've said is right, then the following is false :
(from FlyAround JAR Bank)

Posit:

g, the longitude difference
Lm, the average latitude
Lo, the latitude of the tangent

The correct formula expressing the travel precession applied during a transoceanic and polar navigation, is equal to:

Right answer (according to FlyAround): 15°/h sin(Lm)

Do you agree Kieth ?

Thanks again.

Emmanuel.