Arthur Berry, A Short History of Astronomy
“ The theory of the “reduction” of observations (chapter X., § 218) was first systematised and very much improved by Friedrich Wilhelm Bessel (1784-1846) , who was for more than thirty years the director of the new Prussian observatory at Königsberg. His first great work was the reduction and publication of Bradley’s Greenwich observations (chapter X., § 218) . This undertaking involved an elaborate study of such disturbing causes as precession, aberration, and refraction, as well as of the errors of Bradley’s instruments. ”
