This book provides, for the very first time, a critical edition and an English translation (accompanied by critical notes and technical analyses) of the chapter on spheres (golādhyāya) from Nityānanda’s Sarvasiddhāntarāja, a Sanskrit astronomical text written in seventeenth-century Mughal India. Readers will learn how terrestrial and celestial phenomena were understood by early modern Sanskrit astronomers using spherical geometry. The technical discussions in this book, supported by the critically edited Sanskrit text and geometric diagrams, offer an opportunity for historians of the astral sciences to understand developments in astronomy in seventeenth-century Mughal India from a more nuanced perspective. These are supplemented through explorations of modernity, mathematics, and mythology and how they thrived within Sanskrit astronomical discourse at the courts of the Mughal emperors. This book will be of interest to historians and philosophers of science, in particular those interested in the history of non-Western astral sciences. The book will be a valuable resource for scholars studying the general history of Sanskrit astronomy in the Indian subcontinent as well as those interested in the technical aspects of Sanskrit and Indo-Persian astronomy in Mughal India.