2.1.1.9.

"Aspherical mirror" means a mirror composed of a spherical and an aspherical part, defined in 2.1.1.7 and 2.1.1.8 respectively, in which the transition of the reflecting surface from the spherical to the aspherical part has to be marked.
As an example, the curvature of the main axis of the mirrors may be defined in the x/y coordinate system defined by the radius of the spherical primary calotte with:

 a7c0
2.1.1.9. "Aspherical mirror"means a mirror composed of a spherical and an aspherical part, in which the transition of the reflecting surface from the spherical to the aspherical part has to be marked. The curvature of the main axis of the mirror is defined in the x/y coordinate system defined by the radius of the spherical primary calotte with: a0c0