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.