Calculating Point Illumination Using a Programmable Pocket Calculator

A program using the inverse-square method and suited for a Hewlett-Packard Model 67 pocket calculator is discussed. Point illumination may be calculated at any nodal point of a square grid 1000 by 1000 for an arbitrary arrangement of 10 point luminaire sources placed at nodal points of the grid. Grid dimensions and particular luminaires are specified by the user.