The Kapal Yantra was an astronomical instrument used for solving astronomical problems and recording the coordinates of celestial bodies in both the azimuth-altitude and equatorial systems. It was a part of the Jantar Mantar observatory in Jaipur, India. The Kapal Yantra consisted of two sunken hemispheres, each with a map of the heavens engraved on it, showing the positions and movements of celestial bodies. The Kapal Yantra was also known as the Kapala Yantra, which means "water instrument" in Sanskrit. It is not related to the Kapal Bhati breathing technique, which is a yoga practice that involves rapid exhalations to stimulate the abdominal organs and improve blood circulation.