images from the khagol mela at jantar mantar during winter solstice 2009

working at Ram Yantra

Explaining jaiprakas yantra

explaining working of samrat yantra

for more image click here

WINTER SOLSTICE ACTIVITIES

WINTER SOLSTICE ACTIVITIES FOR SCHOOLS:

1. Find the sun angle on the day of the solstice to see what altitude the sun attains when its on the southernmost side.

2. Track Shadow created by sun

Use a Gnomon to create a shadow at local noon. Measure this shadow over a few days, centering the days before and after the winter solstice.

WINTER SOLSTICE - Dec. 21st 2009

The Shortest Day of the Year 

KHAGOL MELA

at JANTAR MANTAR

Organised by SPACE and Nehru Planetarium jointly

21 December 2009, what is so special about this day? It's the shortest day of the year for people living on the Northern side of the Equator and is called the Winter Solstice. But what does it mean exactly?

We know that the Earth rotates about itself and it is tilted a bit. It also revolves around the Sun in an elliptical orbit. Because of this tilt of the Earth, each day, the Sun takes a different path in the sky as viewed from the Earth. But there are two days in the year when the Sun shines directly over the Tropic of Capricorn (Winter Solstice in Northern Hemisphere) and the tropic of Cancer (Summer Solstice in Northern Hemisphere) respectively. On the day of Winter Solstice, North Pole tilts away from the Sun and South Pole tilts towards the Sun. The Winter Solstice occurs exactly when the earth's axial tilt is farthest away from the sun at its maximum of 23° 26'. So the Sun shines at lowest heights in Northern skies and at maximum heights at Southern skies. It results in the shortest day in the Northern Hemisphere but at the same time it’s the longest day in Southern Hemisphere. So for people in Southern Hemisphere it’s a Summer Solstice.

Winter Solstice indicates winter at its peak. After this, the length of the day starts increasing and it reaches a point where day and night becomes equal in length at Vernal or Spring Equinox. The day continues to grow longer till Summer Solstice, the longest day.

On 21st December ‘09, the Winter Solstice will be at 17:47 UT or 23:17 IST. In New Delhi, sunrise on winter solstice day is at 7:10 am and sunset is at 5:29 pm making it a day which is about 10 hours in duration.

by

S.P.A.C.E. (Science Popularisation Association of Communicators and Educators)