what was the primary function of the kapālayantra

The Kapālayantra was an equatorial sundial instrument used to determine the suns azimuth. It was invented by Indian mathematician and astronomer Bhaskara II (1114–1185 CE) and was used to determine the position of the sun in the sky. The Kapālayantra was one of several instruments used in Indian astronomy to measure time and track the movements of celestial bodies.