The Astronomical Observatories of Jai Singh c9.s1.8

c9.s1.8

29. The Jai Prakāś is called by Jagannāth sarva yantra śiromaṇi ‘the crest jewel of all instruments.’ It is a hemisphere, on the concave side of which are mapped out certain co-ordinates. Cross wires are stretched north to south and east to west, and the shadow of the intersection of the wires, falling on the surface of the hemisphere, indicates the position of the sun in the heavens other heavenly bodies can be observed direct by ‘placing the eye’ at the proper graduated point, and observing the passage of the body across the point of intersection of the wires. For this purpose passages are cut into the hemisphere, and the instrument is duplicated.