The Astronomical Observatories of Jai Singh c9.s1.29

c9.s1.29

Jagannāth’s description of the Digamśa Yantra is as follows :—“Make a circle on the ground with any radius. This circle is called the horizon. We shall have to make three horizons here. On the first circle build a solid pillar. On the second circle build a ring-like wall as high as the pillar on the first circle. On the third circle make a ring-like wall twice as high as either of the former. On all these horizons mark the east to west and north to south lines and degrees and minutes. Stretch tightly two threads across the exterior wall, to represent the east and west and north and south lines, intersecting at right angles over the centre of the horizons. At the centre of the pillar fix securely one end of a string, and to the other end of the string fasten a stone and place it over the edge of the third horizon. This thread is called the ‘thread of the circle of vision.’”