A treatise on spherical astronomy
A university-level textbook on spherical astronomy by Sir Robert Stawell Ball, published by Cambridge University Press in 1908 for students of mathematics and observational astronomy. The figures are line diagrams in pen: circles with tangent lines and labelled radii, orbital ellipses with directional arrows, and curved paths marked with Greek letters, dotted angle arcs and zodiac symbols for Aries and Libra.
