Weighted Solution of Longitude Equations

Abstract

Most of the error in the determination of longitude is caused by error in pointing, which is a displacement of direction. Only a negligible percentage is due to errors in time observations. Therefore, in the adjustment, the errors must be considered as displacements, expressed in seconds of arc, and not as time which, as a different yardstick of displacement, differs with every star. The use of the Mayer formula by weighting the observation equations by cos2δ is here recommended; this results in a simpler form of the equation, with less work and a more logical estimate of the true value.