Meridional plane

The meridional plane to point P contains the great circle, which u. a. runs through points Z, P, H.

Meridional planes in a spherical coordinate system contain the polar axis. You are thus perpendicular to the equatorial plane . All directions within a meridional plane form a meridian .

In the case of a rotationally symmetrical optical system, for example, the optical axis is chosen as the polar axis of the coordinate system .

See also sagittal plane .