Armillary spheres were part of the Sanskrit astronomical tradition, and had been used for understanding the structure of the heavens. Goladīpikā (‘Illumination of the sphere’) is a text in two versions by the same author which deals with structures of the armillary sphere and various related astronomical topics. A close examination of the ways the armillary sphere is described in the two versions of the text will help us understand the main characteristics of the two versions of Parameśvara's Goladīpikā and the reasons why the author duplicated his treatise. This case study thus demonstrates how astral sciences sources from the same author may present mathematical practices surrounding the same instrument in contrasting and complementary ways according to intention.