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.
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