Drive for projector adjustment - defines three angles by alerbraic equation so that projector may be correctly aligned to illuminate positions of solar planets

摘要

The drive system is intended to adjust the position of a projector in a planetarium and includes an elliptical track wherein the track has a midpoint (M), major and minor semi-axis (a, b) a focal point (S) and a planetary rotation angle (V) from the major axis and (Ep) from the mid-point. To ensure the correct location of a planet when projected, the eccentricity (e) of the ellipse is defined by the equation for the mean radius r = a/2 (1 + square root 1-e2) and projection angles (gamma) (phi) delta) are defined by cos (gamma) = square root (1-e)/(1+e) cos (phi) = (Ra-Ri)/(Ra+Ri) cos (delta) =square root (1-e2). Where Ra and Ri are the outer and inner planet radii. Numerical data are given for Mercury, Venus, Mars, Jupiter and Saturn.