Nadi Valve Yantra

Nadi Valve Yantra

This instrument made in the plane of the celestial equator has two – the north and the south parts. When the Sun is in the northern hemisphere for six months, the northern hemisphere disc is illuminated. But when the sun is in the southern hemisphere for the remaining six months, the southern disc is illuminated. The exact time of Ujjain is known by the shadow of the nails fixed parallel to the Earthâs axis in between these two parts.

This instrument is used to ascertain whether a celestial body is in the northern or the southern half. Observe a desired planet straight from a suitable point on the round edge of the northern part. If it is visible, then deem it to be in the northern hemisphere, otherwise it is in the southern one, likewise, information could be had from the southern part.