Medical Definition of nodal point
: either of two points so located on the axis of a lens or optical system that any incident ray directed through one will produce a parallel emergent ray directed through the other.
Where is the nodal point?
The first (front) nodal point is the position on the optical axis of a lens where the entering ray crosses the optical axis. The second (rear) nodal point is the position on the optical axis of a lens where the departing ray crosses the optical axis.
Where is nodal point and what is its significance?
Either of a pair of points situated on the axis of an optical system so that any incident ray sent through one will produce a parallel emergent ray sent through the other. The distance between leveling network nodal points and GNSS permanent stations is not a constant value.
