The Astronomical Observatories of Jai Singh c11.s2.t1.4

c11.s2.t1.4

Shasṭhāṃsa Yantra.—The Shasṭhāṃsa Yantra, or sextant instrument, is a huge convex arc of 60 degrees, and of 28 feet 4 inches radius, lying in the meridian. There are two pairs of such arcs built into the masonry that supports the east and west ends of the Samrāṭ quadrants. Small holes in the roof of each structure allows the sunlight to fall on the arc at noon. The instrument is capable of giving very accurate results, but the readings are said to be in error to about 4 minutes.