1 - I am trying to figure out the longitude at which a geodetic great circle reaches its apex. (I have a point and the azimuth at that point identifying the circle) I have found a good resource that shows how to find the maximum latitude itself (and the azimuth at that latitude) but I cannot figure out how to find the longitude at that point.
2 - Also related how can we find the longitudes at which a geodetic great circle intersects a given parallel?
EDIT: The provided link shows sections from the book The 3-D Global Spatial Data Model Foundation of the Spatial Data Infrastructure Earl F . Burkholder
EDIT2: If it is of any help i have access to forward/inverse geodesy functions. I can find a point and the azimuth at that point given a point-bearing-distance. I can find the distance-bearing between any given 2 points.