The Astronomical Observatories of Jai Singh c8.18

c8.18

The *Chakra Yantra* (circle instrument) is an equatorial. There are two at Jaipur each 6 feet in diameter (figure 57) and one at Benares, 3 feet 7 inches in diameter. The *Chakra Yantra* is fixed so as to revolve about an axis parallel to the earth's axis. At the southern end of the axis of the instrument is a separate graduated circle, fixed on the supporting pillar. The axis carries a pointer, which indicates the hour angle on the fixed circle; and the main movable circle carries an index and sighter (figure 68).