Plane \mathbb{G} can be considered the longitude plane because the great circle made by its intersection with sphere S is always a line of longitude. Plane \mathbb{B} can be considered the tangent plane since it always contains a line tangent to circle C at point P. The dihedral angle between planes \mathbb{G} and \mathbb{B} is angle \alpha, the angle of interest.

Plane \mathbb{Y} can be considered the elevation plane and it stays perpendicular to plane \mathbb{G} and passes through sphere center SO and point P. The smallest angle between the cardinal axis of the sphere and plane \mathbb{G} is angle \lambda , or ∠SNSOP.

Point P can be defined as an arc length along circle C equal to angle \phi, or ∠SNCOP.

The angle between the axis of cone N and the cardinal axis of sphere S is angle \upsilon, or ∠SNSOCO.