Sun Dial

Sun Dial

The upper planes of the two walls on the sides of the steps in the middle of this instrument are parallel to the axis of the earth. In the direction of the planes the pole star is visible. To the East and the West of the wall the quarter of a circle is formed in the plane of the Celestial equator on which hours, minutes and a third part of a minute are engaged.

When the Sun shines in the sky, the shadow of the edge of the wall falls on some mark indicating local time of Ujjain be calculating the hour and minutes. By adding minutes to this clear time table given on the east and the west side of the instrument, one knows the Indian Standard Time.

This Instrument is mainly used to find out the declination of any celestial body from the celestial equator towards the north or the south. First find out the particular point on the edge of the quadrant from where the centre of the celestial body could be observed to coincide with the edge of the wall. The reading at this point of the wall gives the declination.

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.