The Astronomical Observatories of Jai Singh c10.9

c10.9

In the mass of masonry work that supports the east quadrant is a chamber which contains the *Shasthāmśa Yantra*. This is a large graduated arc 60 degrees in length, built in the plane of the meridian; and through a small orifice near the top of the quadrant the sun, as it passes the meridian, shines on the arc and indicates its meridian altitude, from which its declination can be directly deduced. The chamber was closed up when the observatory was restored in 1910.