Definition

In optics, one of the two points on the OPTICAL AXIS of a LENS (or a system of LENSES) such that a RAY emergent from the second point is parallel to the RAY incident at the first. The first nodal point is referred to as the front nodal point or incident nodal point,and the second nodal point as the rear nodal point or emergent nodal point. An AMPHIDROMIC POINT. In ASTRONOMY, a NODE.