Location of the rotation axis of a tumbling cylindrical earth satellite by using visual observations: Part I: Theory

Previously published methods for location of the rotation axis of an Earth satellite using visual observations have relied upon a continuous recording of its brightness variations—the photometric signature. A method is described for locating the axis by using simpler data: observations of the ratio of maximum brightness to minimum brightness during a rotation period are required. Each observation identifies an area of the celestial sphere towards which the axis must point. Several observations are required to limit the areas indicated and to remove ambiguities. The method is demonstrated, using estimates of brightness ratio obtained by visual observers.