Ujjain: Spring equinox occurred on March 21 in Ujjain. Equinox is the time of the year when both day and night time extends to 12 hours each. The equinox occurs when earth’s equator passes through the centre of the sun, that is when the sun shines directly on the equator and the length of day and night is nearly equal.
After March 21, the sun will enter the Northern Hemisphere and Aries sign. The length of day starts increasing and night becomes shorter. This transition will continue till June 21 which marks the summer solstice when sun is directly over the Tropic of Cancer in the Northern Hemisphere and is the longest day.
Superintendent of Government Jivajirao Observatory, Rajendra Prakash Gupt informed that this beginning of transition of sun was seen by ‘Shanku (Gnomon) Yantra’ and ‘Nadivalaya Yantra’ from the observatory. With the help of the shadow of the gnomon, the angle of elevation and zenith distance of the sun can be determined. On March 21, the shadow of the gnomon was seen on the equatorial line whole day, which infers that the length of day was equal to night.
